CHEM. LIB.
QD
501
J67
B 397769
Studies in Catalysis.
DISSERTATION
:
1
SUBMITTED TO THE BOARD OF UNIVERSITY STUDIES OF
THE JOHNS HOPKINS UNIVERSITY IN CONFORMITY
WITH THE REQUIREMENTS FOR THE DEGREE
OF DOCTOR OF PHILOSOPHY
BY
JAMES M. JOHNSON
BALTIMORE
1907
EASTON, PA. :
ESCHENBACH PRINTING COMPANY.
1907.
{
7
1
kolam 4a 5-9 ubaceboft veldagshowgifta pt** **~
Studies in Catalysis.
Chemical Library
QI
501
,567
DISSERTATION
SUBMITTED TO THE BOARD OF UNIVERSITY STUDIES OF
THE JOHNS HOPKINS UNIVERSITY IN CONFORMITY
WITH THE REQUIREMENTS FOR THE DEGREE
OF DOCTOR OF PHILOSOPHY
BY
JAMES M. JOHNSON
BALTIMORE
1907
EASTON, PA. :
ESCHENBACH PRINTING COMPANY.
1907.
дзьповаю
CONTENTS.
Page
4
•
5
6
Acknowledgment.
•
General Discussion..
!
On the Reactions between Thiourazoles and Alkyl Halides...
On the Rearrangement of Acetylhalogenaminobenzene Derivatives into
Halogen Acetanilide Derivatives..
General Discussion of the Hydrolysis of Amides, Cane Sugar, Oximes,
and Esters...
•
12
44
On the Inversion of Cane Sugar in Aqueous Solutions of Acids.
On the Reactions of Carbonyl Compounds with Hydroxylamine and
with Hydroxylamine Hydrochloride..
On the Reaction of Acetone with Phenylhydrazine and Phenyl-
hydrazine Hydrochloride..
•
51
•
55
80
On the Formation and Saponification of Esters and the Theory of Re-
versible Catalytic Reactions..
81
Conclusions.
102
Biographical...
182319
103
ACKNOWLEDGMENT.
The author takes pleasure in expressing his gratitude to
President Remsen, Professor Morse, Professor Jones, Professor
Renouf, Associate Professor Acree and Dr. Tingle for instruction
in the lecture room and laboratory. Especial thanks are due
to Associate Professor Acree, under whose personal direction
this investigation was made.
Studies in Catalysis.
Such reactions as the saponification of esters, and the
hydrolysis of amides, nitriles, oximes, cane sugar, etc., by
water, the formation of esters from acids and alcohols, and the
rearrangement of acetylhalogenaminobenzene derivatives into
halogen acetanilide derivatives¹ are accelerated by acids. The
rate of transformation of the cane sugar, esters and amides
can be represented by the following equation:
dx
dt
= KCsub X CHX CH₂O,
in which K is the saponification constant, Csub the concen-
tration in gram molecules per liter of the substance which is
being hydrolyzed, С the concentration of the hydrogen ions
and CH₂O the concentration of the water, which in dilute
water solutions is practically constant.
H
In the hydrolysis of amides and oximes in dilute
water solution the amide and oxime and also the hydro-
gen ions are used up and the reaction appears to be
bimolecular. In the inversion of cane sugar and the sapon-
ification of esters in dilute aqueous solutions, however, the
concentrations of the hydrogen ions and of the water are not
appreciably changed and the reaction appears to be mono-
molecular.
Chemists³ have long known that we have not data sufficient
¹ Acree and Hinkins: Am. Chem. J., 28, 370; Dental Cosmos, June, 1901. Acree
and Johnson: Am. Chem. J., 37, 410.
2 Ostwald: J. prakt. Chem., 135, 1 (1883). Remsen and Reid: Am. Chem. J., 21,
284. Reid: Ibid., 24, 397.
Ostwald: Z. physik. Chem., 34, 248. Luther and Schilow: Ibid., 46, 777. Weg-
scheider: Ibid., 34, 290. Wagner: Ibid., 28, 33. Slator: Ibid, 45, 512. Bray: Ibid.,
54, 463. Kaufler: Ibid., 55, 502. Walton: Ibid., 47, 209. Brode: Ibid., 37, 290.
Schilow: Ibid., 42, 641. Bredig and Ikeda: Ibid., 37, 1. Bredig and Walton: Z. f.
Elek. Chem., 9, 117. Bredig and Stern: Ibid., 10, 585. Bredig: Ibid., 11, 528. Bredig
and Haber: Z. anorg. Chem., 17, 284. Kastle and Loevenhart: Am. Chem. J., 24,
491; Ibid., 29, 397, 563. Kastle: Ibid., 27, 481. Kastle and Clarke: Ibid., 26,518. Kastle,
Johnston and Elvove: Ibid., 31, 521. Kastle and Smith: Ibid., 32, 376.
6
to tell from the reaction constants whether in such reactions
intermediate compounds are formed which are the substances
really undergoing transformation. One school has held that
in such catalytic reactions the catalyzer does not enter into
combination with any substance present, but affects the ve-
locity of the reaction much as a change of solvent does. An-
other school, however, believes that the velocities of some
reactions are increased or decreased because the catalyzer
enters into combination with some substance or substances
present and the new complexes have reactivities different
from those of the complexes from which they were formed.
The object of the present paper is to discuss some of these re-
actions from this latter point of view.
In those reactions discussed in this communication it may
be said that "When a substance added to a solution in which a
certain reaction is taking place causes an increase or decrease
in the velocity of that reaction, without being itself altered at the
end of the reaction, it does so because it unites to some extent-
with some compound or compounds present and causes an in-
crease or decrease in the concentration of some substance taking
part in the reaction, or because it forms some new substance
(or substances) which yields the same end-products more or less
readily than did the substances in the original solution. Of
course, the solution conditions, such as volume, solvent, tem-
perature, etc., must not be changed."
ON THE REACTIONS BETWEEN THIOURAZOLES AND ALKYL
HALIDES.
Phenylthiourazole¹ and phenylurazole, and their salts react
with alkyl halides and form esters. In a solution of an alkyl
halide and phenylthiourazole there are present both molecular
and ionized phenylthiourazole, and the velocity of the re-
action might be proportional to the concentration of the urazole
ions, or to that of the urazole molecules, or to both alike.
The reaction velocity would then be expressed by the equa-
tions:
¹ Acree: Am. Chem. J., 27, 118; 31, 185; 32, 606; 37, 71,361; 38, 1. Ber. d. chem.
Ges., 35, 553; 36, 3139; 37, 184, 618.
7
dx
= KCurion X Calkyl halide,
(1)
dt
dx
= KCurmol salt X Calkyl halide,
(2)
dt
or
dx
KCur Calkyl halide,
(3)
dt
depending upon whether the urazole ions, molecules, or both
alike, react with the alkyl halide.
The salts are partly hydrolyzed,
UrNa+ H₂O→→→ NaOH + UrH
(4)
and in a solution of a thiourazole salt and an alkyl halide the
alkyl halide may react with the urazole ions, the molecular
urazole salt or the free thiourazole formed from the salt by
hydrolysis. The equations expressing these reactions are
dx
KCurmol salt X Calkyl halide,
(5)
d.
dx
— KCurion × Calykl halide,
(6)
dt
dx
KCur salt Calkyl halide,
(7)
dt
dx
KCur acid × Calkyl halide,
(8)
dt
1
in which, as above, Calkyl halide represents the concentration
in gram molecules per liter of the alkyl halide present at any
moment, Curion the concentration of the urazole ions, Curmol salt
the concentration of the undissociated urazole salt, and
the concentration of the undissociated acid, and Cur
the total concentration of the urazole.
Cur acid
In order to decide between these possibilities it is evidently
necessary to know the relative amounts of urazole ions and
molecules and the actual velocity of the reaction. In the
reaction between the phenyl thiourazole and the alkyl halide
8
there was found a gradual decrease in the value of the constant
obtained by substituting the necessary data in the equation
for the reaction of the second order
x
t(A-x)
=AK and
these constants were lowered very considerably by the addition
of hydrochloric acid. It is evident that the halogen acid
liberated in the reaction,
UrH + C₂H₂I → UrC₂H, + HI,
suppresses the ionization of the phenylthiourazole. Since the
velocity constant of the reaction is also lowered, it would be
suspected at once either that (1) the urazole ions are the prod-
uct chiefly concerned in the reaction with the alkyl halide
or (2) that the halogen acid reacts in some way with some of
the substances present and lowers the reaction velocity because
the product formed by the halogen acid and the other substance
can not react so readily with the alkyl halide.
Since the addition of an alkali to the solution of the phenyl-
thiourazole and the alkyl halide greatly increases the velocity
of the reaction, and since the salts of such weak acids are
more highly ionized than the acids themselves, it would be
suspected at once that the urazole ions are the substances
which are chiefly concerned in the reaction with the alkyl halide.
But such a conclusion would be justified only in the case that
absolute agreement is found between the velocity constants
and the concentration of the ions. It may be stated once
for all that such agreement has been found experimentally.
The urazole ions react with the alkyl halides entirely in ac-
cordance with the demands of the above equations. If the
other urazole groups are concerned in the reaction it is only
to a minor extent. Messrs. Brunel, Johnson and Shadinger
have found that various salts of the urazoles react with the
alkyl halides entirely in accordance with what is known con-
cerning the ionization, hydration, and ionic velocities of the
salts in such solutions.
The velocity constant of the reaction and the ionization of
the urazole are both suppressed by the addition of other sub-
stances having an ion in common with the urazole, whether
9
*
the urazole be in the form of the free acid or a salt. It has
been found in general that alkyl halides react with the anions
of hydroxides, carbonates, thiourazoles, urazoles, thioacetic acid
and other substances. It should be stated that it has been
definitely proved that our results are not in harmony with
the hypotheses that the alkyl halides form alkyl derivatives
(1) through intermediate dissociation into alkyl and halide
ions, as Lobry de Bruyn and Steger¹ supposed, (2) through
the union of the alkyl halide with cathions to form the cathion
+
complexes M.IC,H, assumed by Euler,2 (3) nor through the
intermediate dissociation of the alkyl halides into a halogen
acid and an unsaturated alkylene or aklylidene residue
C₂H₂I => CH,CH) + HI,
assumed by Nef.3 The hypothesis might be advanced that
in the reactions between alkyl halides and urazoles, hydroxides,
carbonates, etc., the alkyl halide unites with the anion and
forms a very unstable complex anion which immediately de-
composes into iodide ions and an alkyl urazole, hydroxide
or carbonate:
C₂H₂I+ OH
-- HO'T'HƆ ←=
C₂H₂OH + I.
Such an assumption, however, is purely gratuitous and will
be subjected to an experimental test.
It has been shown above, then, that acids, alkalies and salts
influence the above reactions. Hydrochloric acid and hydro-
iodic acid act as negative catalyzers and lower the value of
the velocity constant for the reaction between alkyl halides
and phenylthiourazole, because the halogen acid suppresses
the ionization of the phenylthiourazole, and hence causes a
decrease in the concentration of the urazole ions, one of the
two substances reacting according to equation (1). The
addition of sodium hydroxide to the solutions of the phenyl-
thiourazole and alkyl halide causes an increase in the velocity
of the reaction because the sodium hydroxide reacts with the
1 Rec trav. Chim, 18, 311
2 Ber. d. chem. Ges., 39, 2726.
• Ann. Chem. (Liebig), 298, 202; 309, 126; 310, 316; 318, 1, 137; 335, 191.
ΙΟ
phenylthiourazole and forms a sodium salt which furnishes the
solution with a much greater concentration of urazole ions
than does the free acid. Likewise, sodium iodide acts as a
negative catalyzer, and lowers the velocity constant, for the
reaction between sodium phenylthiourazole and ethyl iodide,
because the sodium ions from the sodium iodide cause a sup-
pression of the ionization of the sodium phenylthiourazole
and a diminution of the concentration of the urazole ions.
The above work then shows that acids, bases and salts may
act as negative or positive catalytic agents for certain reactions
because they cause a change in the concentration of an inter-
mediate product in the reaction. The intermediate product
in the above reaction between phenylthiourazole and alkyl
halides is the phenylthiourazole anion.
The following tables of work by Mr. G. H. Shadinger give
a short resumé o some of the experimental results spoken
of above. A large amount of work along these lines has been
done by Messrs. R. F. Brunel, J. M. Johnson and G. H. Shad-
inger, which will be reported later in detail. The reaction
was followed analytically by titrating the unchanged phenyl-
thiourazole, or the sodium salt, with o.1 N iodine solution.
The solvent was 50 per cent alcohol and the solution was 0.05 N
with respect to the phenylthiourazole, or sodium salt, and the
ethyl iodide. The temperature was 50°. T gives the time
in minutes and A the number of cc. o. 1 N iodine solution re-
quired to titrate 20 cc. of the solution at the beginning. A-x
is the unchanged, and x the transformed urazole and ethyl
iodide, expressed in cc. o.1 N iodine. AK is the constant
calculated for a bimolecular reaction, AK
x
t(A — x)'
on
the assumption that A is equal to 5 cc. o.1 N iodine.
50°; 0.05 N 1-Phenyl-3-thiourazole; and 0.05 N ethyl iodide.
AK.
T.
A.
A-x.
x.
5
4.90
4.II
0.79
0.039
ΙΟ
4.90
3.57
1.33
0.038
15
4.90
3.18
1.72
0.037
31
4.90
2.46
2.44
0.033
60
4.90
1.88
3.02
0.027
120
4.90
I.29
3.61
0.024
240
4.90
0.66
4.24
0.027
II
50°; 0.05 N 1-Phenyl-3-thiourazole; 0.05 N ethyl iodide; and
0.25 N HCl.
:
T.
60
A.
4.71
A-x.
3.54
x.
I.17
AK.
0.00584
The first table shows the constant decrease in the value of
AK as the reaction proceeds, due to the increasing suppres-
sion of the ionization of the phenylthiourazole by the hydro-
iodic acid formed in increasing amount as the reaction pro-
ceeds. The second table shows very sharply the great de-
crease, caused by the 5 molecules of hydrochloric acid, in the
ionization of the phenylthiourazole and the consequent de-
crease in the velocity constant of the reaction. The halogen
acids act as negative catalyzers because they cause a decrease
in the concentration of the urazole ions, and a consequent
decrease in the velocity of the reaction.
50°; o.1 N Sodium 1-Phenyl-3-thiourazole; and o.1 N ethyl
iodide.
I.
A'.
A' x.
X.
A'K'.
AK.
ΙΟ
9.44
3.80
5.64
0.156
0.0780
20
9.44
2.26
7.18
0.168
0.0840
40
9.44
1.30
8.14
0.165
0.0825
81
9.44
0.70
8.74
0.163
0.0815
190
9.44
0.30
9.14
0.169
0.0845
In this table AK represents the velocity which the reaction
would have if the concentrations were the same as in the above
reaction between the phenylthiourazole and ethyl iodide.
This table shows that the velocity constant for the reaction
between the sodium thiourazole and the ethyl iodide is twice
as great as that for the reaction between the phenylthiourazole
and the ethyl iodide, because the sodium salt is more highly
ionized. It was shown in other experiments that the addi-
tion of sodium iodide or sodium chloride to the solution causes
a decrease in the velocity constant with the decrease in the
percent of ionization of the sodium phenylthiourazole. The
sodium iodide and sodium chloride act as negative catalyzers
because they cause a decrease in the concentration of the
urazole ions, and a consequent decrease in the velocity of
the reaction.
12
The following table worked out by R. F. Brunel and J. M.
Johnson¹ shows that potassium iodide acts as a negative
catalyzer in the reaction between potassium 1-phenyl-4-
methylurazole and ethyl iodide in 40 per cent alcoholic solu-
tion at 60°. The solutions are 0.3 N with respect to the ethyl
iodide, potassium 1-phenyl-4-methylurazole, and the potas-
sium iodide added. The second and third columns contain
the percent of ethyl ester formed and the values of AK when
no potassium iodide is added to the solution, while the fourth
and fifth columns give the per cent of ester formed and the value
of AK when one molecular quantity of potassium iodide is
added to the solution. It is clear that the potassium iodide
acts as a negative catalyzer because it causes a decrease in
the per cent of ionization of the potassium 1-phenyl-4-methyl-
urazole.
0.3 N Potassium urazole + 0.3 N
ethyl iodide.
Time in
hours.
0.3 N Potassium urazole + 0.3 N ethyl
iodide +0.3 N potassium iodide.
Per cent
Per cent
reacted.
AK.
reacted.
AK.
0.5
18.00
0.44
12.9
0.30
1.0
30.35
0.45
23.9
0.31
2.0
48.20
0.46
40.0
0.33
4.0
62.85
0.42
52.9
0 28
ON THE REARRANGEMENT OF ACETYLHALOGENAMINOBENZENE
DERIVATIVES INTO HALOGEN ACETANILIDE DERIVATIVES.
·
But even in some cases
in which it is
is not easy to
measure the small amounts of intermediate product present,
it will be found possible to prove by the qualitative and quan-
titative study of the reactions that such are present.
Acetylhalogenaminobenzene² derivatives rearrange in the
presence of halogen acids into halogen acetanilide derivatives,
CH,CONCIC,H¸ →→→
CH,CONHCH,Cl,
but are stable in the presence of alkalies. The reaction is not
appreciably reversible. That the reaction is not brought
1 Acree: Am. Chem. J., 37, 71.
2 Slosson: Ber. d. chem. Ges., 28, 3265. Armstrong: J. Chem. Soc. 77, 1047. Chat-
taway and Orton: Ibid., 75, 1046; 77, 134; 79, 274; etc.
13
about by the mere presence of hydrogen ions¹ is shown by the
fact that acetylchloraminobenzene in 16 per cent acetic acid
solution at o° is rearranged about 1,000 times as rapidly by
hydrobromic acid of a given concentration as by hydrochloric
acid in the same concentration. Furthermore, the acetic acid
present in the solution furnishes 1.5 times as much hydrogen
ions as the hydrochloric acid, but the velocity of rearrangement
in the dilute acetic acid is very much smaller than when hy-
drochloric acid is present. Furthermore, a sample of pure
acetylchloraminobenzene which stood several days under
dilute sulphuric acid was recovered unchanged and 99 per-
cent pure, with the melting point 88°. Another proof that
the rearrangement is not caused by the mere presence of
hydrogen ions is furnished by the fact that acetylchloram-
inobenzene in ligroin is changed almost instantly by chlorine
and bromine into parachloracetanilide or parabromacetan-
ilide.
¿
Still further proof that the rearrangement is not caused
by the mere presence of the hydrogen ions, but involves the
union of the hydrogen ions and halogen ions with the
acetylchloraminobenzene is furnished by the order of the
reaction and the qualitative and quantitative study of the
course and nature of the reactions.
Blanksma² found that in the rearrangement of acetylchlor-
aminobenzene by hydrochloric acid,
CH,CONCIC.H¸ +HCl. ⇒
CH,CONHCH,Cl + HCl,
the velocity is proportional to the concentration of the acetyl-
chloraminobenzene and to the square of the concentration of the
hydrochloric acid. The concentration of the hydrochloric acid
remains constant since it is not used up in the reaction. The
constant obtained is that for a monomolecular reaction, which
shows that the acetylchloraminobenzene is the only substance un-
dergoing change in concentration. The fact that the reaction
is monomolecular proves that the rearrangement is intra-
molecular and not intermolecular. If the reaction involved
1 Acree and Johnson: Am. Chem. J., 37, 410.
2 Rec. trav. Chim., 21, 366; 22, 290.
14
the chlorination of the benzene nucleus in one molecule by
the halogen amino group, or some derivative, of another mol-
ecule the reaction would be bimolecular, or of a higher order.
This will be discussed in detail below. In nearly all catalytic
reactions studied heretofore, such as the hydrolysis of esters,
inversion of cane sugar, hydrolysis of amides, etc., the veloc-
ity of transformation has been found to be simply proportional
to the concentration of the hydrogen ions. These two different
cases are very important in that they throw light on the the-
ory of catalysis in general and in that they make it possible to deter-
mine, in cases where only a small amount of the intermediate
compound or salt is present, whether the substance under-
going transformation is the undissociated salt or the ionic
form of the salt. The acetylchloraminobenzene is probably
a very much weaker base than acetamide on account of the
negative phenyl, acetyl and bromine groups attached to the
nitrogen, and its salts will, therefore, be greatly hydrolyzed
in aqueous solutions. Furthermore, the small amount of salt
actually existing will be nearly completely dissociated in the
extremely dilute solution. It follows then that the hydrolysis
of the salt will follow the familiar equation of Arrhenius¹ and
Walker,²
+
CH,CONCIC,Н¸ + H
+
CH₂COÑHCICH
(Chal-x)+CH = KhydCsalt dis
5
Kw
Csalt dis, (1)
Kb
in which Chat represents the original concentration, in gram
molecules per liter, of the acetylhalogenaminobenzene deriva-
tive used, x the concentration of this substance changed
into other products, including the complex salt, (Chal-x)
the concentration of the acetylchloraminobenzene derivative
at the moment equilibrium is established, C, the concentration
of the hydrogen ions, Csalt dis the concentration of the complex
cathion, CH,CONHCIC,H,, Kd the hydrolysis constant,
K, the ion product of water at the temperature, and K, the
+
1 Z. physik. Chem., 5, 1; 13, 407.
2 Ibid., 4, 319; 32, 137. J. Chem. Soc., 77, 5.
H
15
affinity constant of the weak base. The value of Csalt dis
can be calculated for all dilutions when K, and the dissoci-
ation constant for the salt become known. K, is too small to
be measured accurately, by the methods now at hand, but
this will be studied later. Since only a very small amount
of the acetylchloraminobenzene and of the hydrogen ions are
used up in forming the salt, (Chat-x) and Сн, are so nearly
equal to the concentrations that these two would have if no
salt were formed, that no appreciable error is involved in sub-
stituting for the values of (Chat-x) and CH in equation (1)
before any rearrangement occurs, the values of the concentra-
tions that these two would have if either were alone in the
solution. The same may be said for other cases considered
below, as has been discussed by Walker, and this point will
not be considered again. If the dissociated salt were the only
substance rearranging into parachloracetanilide the rate of
formation of the parachloracetanilide would be
+
CH,COŃнCICH
-dC salt dis
dt
-5
+
CH,CONHCH¸Cl + H
dx
dt
Ktrans Csalt dis,
(2)
in which Ktrans is the velocity constant for the rearrange-
ment of the dissociated salt which is present in the concen-
tration Csalt dis• dC. is the small amount of Csalt dis
salt dis
which rearranges in the time dt.
dcsalt dis is exactly equal,
in gram equivalents, to dx, the small amount of product formed
by the rearrangement of the acetylhalogenaminobenzene. We
may, therefore, write dx for the small amount of substance
transformed, whether it be the intermediate compound or the
acetylhalogenaminobenzene. The dx represents an increase
and the dC salt dis a decrease; hence the one is the negative
of the other.
In the total reaction, expressed by equations (1) and (2),
we are dealing with two consecutive reactions. The first is
a reversible reaction involving what may be considered prac-
tically a bimolecular and a unimolecular reaction. The second
is a non-reversible bimolecular reaction. The concentration of
16
Csalt dis
at any moment depends upon the concentrations of the
acetyl halogenaminobenzene, hydrogen ions, and anions, and
upon
the velocities of the two reactions. The first reaction is the
neutralization of the base by an acid, and all such reactions take
place, as a rule, immeasurably rapidly. The second reaction
is, therefore, very slow in comparison with the first, and the
equilibrum expressed in equation (1) is never appreciably
disturbed by the change in the concentration of Csalt dis in
reaction (2). Hence according to (1)
Ko
Csalt dis
(Chal-x) X CH₁
Kw
and equation (2) becomes
dx
Ktrans Ko
(Chal-x) × CH,
dt
Kw
or
!
I
Chal
log
tCH
(Chal-x)
KoKtrans
Kw
K.
(3)
If the base existed entirely as salt the velocity of rearrange-
ment would be Ktrans; but since only a small fraction of the
base exists as salt, the reaction is retarded and the value of
the constant actually obtained for the rate of transformation
of the acetylchloraminobenzene is the value of the real veloc-
ity constant for the substance actually changing into the para-
chloracetanilide divided by the ratio of the amount of base
to the amount of dissociated salt. But according to equation
(3) this constant should be proportional to the concentration
of the hydrogen ions. Experimentally, however, it is found
that the constant varies as the square of the concentration
of the hydrogen ions. It is, therefore, certain that the ion
+
CH¸COÑнCICH¸ is not the substance which chiefly yields
the parachloracetanilide, although it may do so to a very small
extent. We must look elsewhere then for the substance which
changes directly into parachloracetanilide.
Since the amount of molecular salt present is very small,
the formation of this undissociated salt will follow the require-
17
ments of the mass law as discussed above for the complex
cathion and give equation (4)
CH,CONCIC.H, + H+ Cl
(Chal−t) XCHX Ca
CH.CONHCL,CH.
Kaffin Kw
=
Csalt, und (Chal - x) X CH(CI),
(4)
Kb
in which Kaffin
is the dissociation constant of the salt, the
molecular form of which has the concentration Csalt und
If the undissociated salt yields the parachloracetanilide
the rate of transformation of the acetylchloraminobenzene
would be expressed by the equation
CH.CONHC.,C H =
CH,CONHCH.Cl + HCl
-d Csalt und
dt
dx
dt
KtransCsalt und.
(5)
in (5) we can
It is evident from (4) that instead of Csalt und
substitute
Kh
Κω
Kw Kaffin
(Chal-x) X CH X Ca or
and we then obtain
dx
Ktrans Kb
dt
Kw Kaffin
Ko
KuKaffin
(Chal-x) X CH(CI),
Chat-x) X CH X Ca =
Ktrans Kb
(Chal-x)X CH(C), (6)
Κω
KwK affin
or
I
Chal
Ktrans Kb
= K.
log
tC₁(a)
(Char- x)
Kw Kaffin
But equation (6) expresses the results actually obtained ex-
perimentally. In other words, the velocity of the reaction
shows that the substance undergoing change is the undisso-
ciated salt in (4) and not the cathion of this salt in (1). In
18
entire harmony with this is the fact that different acids
(HC1, HBr, H₂SO4, CH,COOH) do not give reaction constants
bearing the relation to the concentration of their hydrogen ions
demanded by equation (3). All of these acids would give
the same complex cathion in (1). The amount of this cathion
and consequently the rate of transformation of the acetyl-
chloraminobenzene, should be strictly proportional to the con-
centration of the hydrogen ions, whatever the acid, if the re-
action took place according to (1). Such, however, is not
the case.
The fact that three different acids give different velocity con-
stants is predicted by theory if equation (5) represents the
method of change. The undissociated salts formed by all
of these acids can be represented by CH,CONHCIACC₂H,
in which Ac represents the anion of the acid. These different
salts would be expected to, and do, have different velocities
of transformation as will be discussed below. Instead of the
salt represented in the equation (4) another compound, to
give a general illustration applicable in other cases as well as in
the present one, could be formed by the addition of two anions
or two cathions to the acetylchloraminobenzene as follows:
CH,CONCIC,H¸ + 2Ac
CH,COÑC1(Ac),C¸H¸ ;
CH,CONCICH¸ + 2ĤCH,CONCIH,CH¸;
CH,CONCIH,CH,
+
CH,CONHCH,Cl + 2H.
This would lead to the same velocity constants as in equation
(6) and as the present work does not decide absolutely between
these two we shall confine our discussion of the case as if it took
place according to equations (5) and (6) as it most probably
does.
The quantitative evidence leads to the belief that acetyl-
chloraminobenzene does not rearrange per se in the above
reactions. The evidence further shows that the positive
ion in equation (1), CH,COÑHCIC,H, is not the substance
undergoing transformation into parachloracetanilide, but that
+
16 5
19
the, undissociated salt CH,CONHCI,C,H, changes into para-
chloracetanilide and hydrochloric acid.
What is the evidence supporting the view that such
a substance, present in only a very small amount at any mo-
ment, can change rapidly enough to account for the reaction
velocity?
5
Jackson and Clarke¹ and also Fries2 have shown that (CH3)2
NBr₂C.H, and other similar substances, which are entirely
analogous to the above salt, rearrange very rapidly into para-
bromdimethylaniline hydrobromide.
The following evidence leaves no doubt that the above is
the correct interpretation of the reaction. If the acetylhalo-
genaminobenzene adds the halogen acid as illustrated above,
we should obtain the same intermediate product from acetyl-
chloraminobenzene and hydrobromic acid as is formed by the
action of hydrochloric acid on acetylbromaminobenzene:
(A) CH,CONCIC,H¸ + HBr
(B) CH,CONBгCH, + HCl
CH.CONHC1BrCH =
CH,CONHCH,Br + HCl.
If this addition product is the substance which rearranges
into the parahalogenacetanilide, we should obtain the same
substance or substances by either of these methods, and the
relative amount of parachloracetanilide and parabromacet-
anilide formed would depend upon the relative tendency
of the chlorine and bromine to enter the benzene nucleus.
It was known beforehand that acetylbromaminobenzene re-
arranges very much more rapidly into parabromacetanilide
than the corresponding chlor derivative yields parachloracet-
anilide; we therefore predicted that from both of the reactions
we should obtain the same product, parabromacetanilide,
and this was happily verified by experiment. The parabrom-
acetanilide obtained seemed to be practically free from para-
chloracetanilide. The formation of the parabromacetanilide
from acetylchloraminobenzene and hydrobromic acid takes
1 Am. Chem. J., 34, 261; 36, 409.
2 Ann. Chem. (Liebig), 346, 128.
20
place according to a reaction of the second order as de-
manded by equation (A) above.
We have further found that when bromine or chlorine is
added to acetylchloraminobenzene in ligroin the substance is
transformed in a few seconds into parabromacetanilide and
parachloracetanilide. The formation of the parabromacet-
anilide was predicted.
CH,CONCIC,H,+ Br₂
CH,CONCIC.H, + Cl₂
CH,CONCIBr₂CH, =>
CH,CONHCH¸Br + BrCl;
CH,CONCI,C,H,
5
CH,CONHCH¸C1 + Cl₂.
The transformation of these acetylhalogenaminobenzenes
in the presence of acids was effected in aqueous acetic acid
solutions. If the cathion in (1) were the substance being
transformed into parahalogenacetanilide this rearrangement
should take place more rapidly in those solutions containing
more water, because in such solutions the salt would be more
completely dissociated. But if the undissociated salt in (5)
is the substance being changed into the halogenacetanilide
the rearrangement should take place more slowly in those solu-
tions containing more water, because there would be less un-
dissociated salt in the solutions containing more water. Since
the concentration of the undissociated salt would be smaller
the velocity of transformation of the acetylhalogenamino-
benzene would be smaller. Since the rearrangements take place
more slowly in those solutions containing more water, the
latter hypothesis and equations (5) and (6) are verified.
Finally, if the undissociated salt were the substance being
transformed the addition of a salt with a common ion should
cause a rise in the velocity of transformation. It is evident
that the addition of potassium chloride to a solution of the
acetylchloraminobenzene and hydrochloric acid would cause
a suppression of the ionization of the complex hydrochloride.
If the undissociated salt is the substance being transformed
it is evident that the increase of the concentration of this sub-
stance by the potassium chloride should cause an increase in
the reaction velocity. The theory has been fully verified
21
experimentally as will be shown below. If the complex ca-
thion were the substance undergoing transformation the ad-
dition of potassium chloride should cause a decrease in the
ionization and velocity of reaction, provided that the potas-
sium chloride does not act per se as an energetic positive
catalyzer. Such is, however, not the case.
It is entirely possible that the rearrangements of deriva-
tives of phenylnitramine, phenylnitrosamine, and phenyl-
sulphaminic acid into derivatives of nitraniline, nitrosoaniline
and sulphanilic acid take place like the above reactions, and
this will be a subject of investigation in this laboratory.
EXPERIMENTAL.
The acetylchloraminobenzene and the acetylbromamino-
benzene used in the following experiments were prepared
by Slosson's¹ method, as the methods of Chattaway and Orton²
and of Armstrong³ were tried without good results.
Five-tenths gram of acetylchloraminobenzene, melting at 85°-
87°, was dissolved in ligroin and 0.25 cc. of bromine were
dropped in; a white precipitate of parabromacetanilide was
formed immediately. This was filtered off after a few moments,
dried and recrystallized from alcohol. It melted at 163°–
167°; when mixed with pure parabromacetanilide, m. p. 167°,
obtained by another method, the melting-point was not low-
ered.
One-half gram of acetylchloraminobenzene, m. p. 85°-87°,
was dissolved in ligroin and a rapid stream of dry chlorine
gas was passed in. After one minute a white precipitate of
parachloracetanilide began to appear. When the precipi-
tation was complete, the substance was filtered off, dried, and
recrystallized from alcohol. It melted at 173°-176°. When
mixed with parabromacetanilide, m. p. 167°, it melted at
165°-170°. When mixed with pure parachloracetanilide, m. p.
176°-178°, made from acetylchloraminobenzene and hy-
drochloric acid, it melted at 176º-178°.
Acetylchloraminobenzene, m. p. 85°-87,° was dissolved
1 Loc cit
2 Ibid.
• Ibid.
22
in glacial acetic acid and treated with dilute hydrochloric acid.
A white precipitate of parachloracetanilide was obtained which,
when crystallized from alcohol, melted at 176°-178°.
Acetylchloraminobenzene, m. p. 85°-87°, was dissolved
in glacial acetic acid and treated with dilute hydrobromic
acid. A white precipitate of parabromacetanilide was obtained
which melted at 165°-167° when crystallized from alcohol.
When mixed with parabromacetanilide, m. p. 167°, obtained
from acetylbromaminobenzene and hydrobromic acid the melt-
ing-point was still 165°-167°. When mixed with pure
parachloracetanilide, m. p. 176°-178°, the melting-point
was lowered to 150°-160°.
One gram of acetylchloraminobenzene, m. p. 85°–87°,
was treated with a large excess of dilute sulphuric acid and
let stand two weeks. The product was filtered off and recrys-
tallized from alcohol. It then melted at 88°-89°. A sam-
ple of 0.2927 gram required 28.80 cc. of 0.1185 N sodium
thiosulphate solution. The substance then was unchanged
acetylchloraminobenzene, 99 per cent pure. This experi-
ment shows that sulphuric acid causes only a very slow change
in the substance. Quantitative experiments given below
show further that this change is very slow when the acetyl-
chloraminobenzene and sulphuric acid are dissolved in aque-
ous acetic acid. The experiment proves very clearly that
the catalysis is not due to the mere presence of the hydro-
gen ions, because the rapidity of rearrangement caused by the
sulphuric acid in a given concentration is very much less
than that produced by an equal concentration of hydro-
chloric acid or hydrobromic acid.
Acetylbromaminobenzene, m. p. 88°, was treated with di-
lute hydrochloric acid. A white precipitate of parabromacet-
anilide was obtained which, when recrystallized from alcohol,
melted at 167°, and this melting-point was not lowered by
mixing the sample with parabromacetanilide obtained other-
wise.
Acetylbromaminobenzene, m. p. 88°, was treated with
dilute hydrobromic acid. A precipitate of parabromacet-
anilide was obtained which, when recrystallized from alcohol,
23
melted at 167°. The melting-point was not lowered by mix-
ing the sample with the above compound, or with pure para-
bromacetanilide obtained otherwise.
Paratolylacetylnitrogenbromide, prepared by Chattaway and
Orton's method, rearranged so quickly on standing, or when
treated with hydrochloric or hydrobromic acid, that it was
impossible to do any quantitative work with this substance.
The paratolylacetylnitrogenchloride used in the rearrange-
ment experiments was prepared by Chattaway and Orton's
method. This substance, when treated with hydrochloric
acid, gave a mixture of paracettoluidide and orthochlor-
paracettoluidide.
Paratolylacetylnitrogenchloride, when treated with a large
excess of hydrobromic acid, gave a red oil from which a com-
pound was obtained by recrystallization from alcohol. This
melted at 107°-108° and was probably impure orthobrom-
paracettoluidide, m. p. 118°.
Paratolylacetylnitrogenchloride, in ligroin solution, was
decomposed by bromine and chlorine, giving, in both cases,
apparently some impure paracettoluidide, melting at 140°—
150°.
REARRANGEMENT EXPERIMENTS.
Experiments with Hydrobromic Acid.
If in the reaction between hydrobromic acid and acetyl-
chloraminobenzene the parabromacetanilide is formed by
the rearrangement of the undissociated hydrobromide of
the acetylchloraminobenzene, the equations wil differ some-
what in form from those used in the work on the rearrange-
ments produced by hydrochloric acid. If the undissoci-
ated salt is formed according to the mass law we have
+
CH¸CONCICH¸ + H + Br
CH,CONHClBrC,H, →→
+
CH,CONHCH,Br+H+ Cl.
(Chal-x-y) (CBr -x-y)CH
Kaffin Kw
Csalt und, (1)
Kb
or, when y is small in comparison with x,
24
(Chat-x)(CBr—x)CH
Kaffin Kw
Kb
Csalt und,
(2)
in which y is the concentration of the salt formed, and x the
concentration of the parabromacetanilide, while the other-
symbols have the same meaning as before.
If now the undissociated salt is the substance undergoing
rearrangement, we have
-dCsalt und
dt
Ktrans Csalt und.
(3)
As discussed above, however, we can substitute for Csalt und
in (3) the corresponding value in (2) and we then get
dx
Ktrans Kb
(Chal-x)(CBr - x)CH
dt
Kaffin Kw
K(Chal-x)(CBr-x)CH.
(4)
When Chat CBr and CH are in equivalent concentrations,
A, equation (4) becomes
ཅུ|€
dx
dt
х
K(A-x)(A-x)A or
=K,
(5)
t(A—x)A²
whereas if only the concentrations of the acetylchloramino-
benzene and of the bromide ions were to be considered the
well-known equation by the second order reaction,
x
t(A-x)A
K,
would hold. We have therefore a method of testing the ques-
tion whether the undissociated salt formed by the union of
the hydrobromic acid with the acetylchloraminobenzene is
the substance rearranging according to equation (5). By
simply varying the value of A, we can see if a constant value
for K is obtained. We must, however, expect some decrease
in the value of K with increase in the value of A for the fol-
lowing reasons: The A in equation (5) is substituted for
(Chat-y) or (CB-y) in equation (1). When y is very small
the error involved in this substitution is small. Since y in-
creases more rapidly than A it is evident that the error becomes
25
larger with increase in A, and since A² occurs in. the denom-
inator in equation (5) the error is still more magnified. In-
stead of A² in equation (5) we should have (A—y)², the value
of which is not known. Since then A² is larger than (A—y)²
and occurs in the denominator the value of K should decrease
with increase in the value of A.
2
Since A² is the function used in equation (5), even a small
error involved in the use of A instead of (A—y) becomes
magnified in A³. If (A-y) equals o. 9 A, the value of K de-
rived from equation (5) is 20 per cent less than it should be,
whereas if (A-y) equals o.6 A the value of K is only one-third
as large as it should be. This fact then accounts to some ex-
tent for the decrease in the value of K in Tables I. and IX. in-
clusive. The results of all the work on the rearrangements
by hydrochloric acid and hydrobromic acid makes it very prob-
able that the above explanation of the cause of the rearrange-
ment is essentially correct. It is probable, however, that
there are other conditions not considered at all in the above
equations which help to cause a decrease in the value of K in
Tables I. to IX., inclusive, and these are now the subject of
investigation.
The experiments in Tables I. to IX. were carried out in the
following manner in a dark room. From 0.2 gram to 2.2 grams
acetylchloraminobenzene were put into a dark colored bottle
holding something more than 600 cc. The solid was then dis-
solved in 60 cc. glacial acetic acid and afterwards 540 cc. water
were added. The contents of the bottle were shaken up
thoroughly and placed in a bath of melting ice. When the
temperature had become constant, 100 cc. were withdrawn
in a pipette and quickly transferred to a beaker containing
1.0-2.0 grams of potassium iodide in 10-20 cc. of water. The
iodine liberated by the unchanged acetylhalogenaminobenzene
derivative was titrated with standard sodium thiosulphate.
From this it was possible to calculate the necessary amount
of standard hydrobromic acid to be added to the remaining
500 cc. of solution to make unimolecular equivalents. The
time was noted when this acid was added; 100 cc. were with-
drawn in a pipette from time to time, added to the potassium
26
iodide solution, and the iodine titrated against sodium thio-
sulphate solution as above. The results gave no constant
at all for a monomolecular equation, but a very fair one
for the bimolecular equation. The time, T, is expressed in
minutes in all of the following tables. In calculating the re-
sults the necessary correction for the change in volume by the
addition of the acid was made. The hydrochloric acid libera-
ted during the reaction acts so slowly, in comparison with the
hydrobromic acid, upon the acetylchloraminobenzene that this
factor is not considered in the above equations.
In Tables I. to IX. inclusive the value K is calculated from
AK on the basis of number of cc. thiosulphate solution used.
K' is calculated from AK on the basis of the number of gram
molecules per liter of acetylchloraminobenzene.
In Tables X. to XIV. inclusive, approximately 2.0 grams of
acetylchloraminobenzene derivative were dissolved in the
same volume of solvent used above. In these tables the value
of K is calculated from that of AK on the basis that the quan-
tity of acetylchloraminobenzene derivative present is equiva-
lent to 20 cc. thiosulphate solution. The values 0.255, 0.260,
and 0.275 of K for acetylchloraminobenzene at 2°, 4° and 5°
agree very closely.
Table I.
0.2 gram acetylchloraminobenzene in 60 cc. glacial acetic
acid and 540 cc. water at 3°; 1.16 cc. of 1.05 N HBr (1 mol.)
added.
t.
Na2S2O3.
A²K.
5.31
21.66
4.32
0.0106
46.16
3.54
0.0108
78.16
2.82
0.0113
114.5
2.28
0.0116
157.16
I.90
0.0114
Average, 0.0III
K, 0.00039
K', 0.13
!
27
Table II.
0.4 gram acetylchloraminobenzene in 60 cc. glacial acetic
acid and 540 cc. water at 3°; 1.91 cc. of 1.05 N HBr (1 mol.)
added.
t.
Na2S2O3.
A²K.
O
8.69
Ι.Ο
8.53
0.0188
3.66
8.10
0.0199
16.0
6.45
0.0217
40.66
4.58
0.0220
95.33
2.70
0.0232
Average, 0.0211
K, 0.00028
K', 0.095
Table III.
0.6 gram acetylchloraminobenzene in 60 cc. glacial acetic
acid and 540 cc. water at 3°; 2.79 cc. of 1.05 N HBr (1 mol.)
added.
t.
Na2S2O3.
KA2.
O
12.69
11.25
8.92
0.0376
18.66
7.40
0.0382
36.33
5.23
0.0392
54.5
4.02
0.0395
76.25
3.16
0.0395
Average, 0.0388
K, 0.00024
Table IV.
K', 0.081
0.8 gram acetylchloraminobenzene in 60 cc. glacial acetic
acid and 540 cc. water at 3°; 3.72 cc. of 1.05 N HBr (1 mol.)
added.
t.
Na2S2O3.
O
16.88
3.08
14.41
8.16
II.55
16.66
8.70
34.33
5.73
62.8
3.60
K, 0.00019
KA2
0.0556
0.0565
0.0564
0.0566
0.0587
Average, 0.0568
K', 0.067
28
Table V.
I.I grams acetylchloraminobenzene in 60 cc. glacial acetic
acid and 540 cc. water at 3°; 5.18 cc. of 1.094 N HBr (1 mol.)
added.
t.
Na2S2O8.
O
24.43
3
18.90
11.66
II.37
20.25
8.06
44.5
4.25
128.5
I.32
K, 0.00017
KA2.
0.0975
0.0984
0.100
0.106
(0.136)
Average, 0.100
Table VI.
K', 0.055
1.6 grams acetylchloraminobenzene in 60 cc. glacial acetic
acid and 540 cc. water at 3°; 7.84 cc. of 1.094 N HBr (1 mol.)
added.
t.
Na,S2O3.
KA2.
O
36.78
1.08
30.10
0.205
3.08
22.00
0.218
IO
12.73
0.189
23.5
6.39
0.202
41.16
3.80
0.210
Average, 0.205
K, 0.00015
K', 0.051
Table VII.
2.2 grams acetylchloraminobenzene in 60 cc. glacial acetic
acid and 540 cc. water at 3°; 10.52 cc. of 1.094 N HBr (1 mol.)
added.
t.
Na2S2O3.
KA2.
O
49.12
0.92
36.46
(0.378)
2.58
26.22
0.338
4.66
18.79
0.347
II.16
9.96
0.352
21.66
5.80
0.344
Average, 0.345
K, 0.00014
K', 0.048
29
Table VIII.
1.0 gram acetylchloraminobenzene. (3 mols.) in 60 cc. glacial
acetic acid and 540 cc. water at 3°; 1.52 cc. of 1.094 N HBr
(1 mol.) added.
B(A—x)
t.
Na,S,Og.
log
—K(A—B)B.
A(B-x)
O
21.62
I
18.80
0.015
1
150
361
888,
16.27
0.015
1
14.82
0.015
13.93
13.94
1440
13.32
Average, 0.015
K, 0.00014
Table IX.
0.333 gram acetylchloraminobenzene (1 mol.) in 60 cc.
glacial acetic acid and 540 cc. water at 3°; 4.53 cc. of 1.094
NgHBr (3 mols.) added.
t.
Na2S2O3.
log
B(A—x)
A(B—x)
===
K(A-B)B.
O
7.14
2.16
6.21
(0.029)
6.25
4.65
14
2.82
0.021
0.022
27.75
I.26
0.021
59
0.20
202
0.00
Average, 0.021
K, 0.00021
30
Table X.
0.8 gram acetylchloraminobenzene in 30 cc. glacial acetic
acid and 265 cc. water at 2°; 3.81 cc. (1 mol.) of 1.05 N HBr
added.
t.
Na2S2O3.
АК.
O
17.31
1.0
14.01
0.236
3.75
9.87
0.196
14.75
4.37
0.203
25.25
2.37
0.252
48.50
1.56
0.208
Average, 0.22
K, 0.255
Table XI.
0.8 gram acetylchloraminobenzene in 30 cc. glacial acetic
acid and 2.70 cc. water at 4°; 4.61 cc. of 1.05 N HBr ( 1 mol.)
added.
t.
Na2S2O3
AK.
O
20.60
I.12
16.57
0.216
2.87
11.56
0.272
7.63
6.44
0.288
15.50
3.30
0.329
33.75
2.18
0.250
Average, 0.27
K, 0.26
Table XII.
0.8 gram acetylchloraminobenzene in 30 cc. glacial acetic
acid and 278 cc. water at 5°; 4.39 cc. of 1.05 N HBr ( I mol.)
added.
t.
Na2S2O3.
AK.
O
19.62
0.87
15.10
(0.34)
3.25
10.28
0.28
8.37
6.01
0.27
16.00
3.72
0.27
32.00
2.18
0.25
Average, 0.27
K,
0.275
31
The reaction between hydrobromic acid and paratolyl-
acetylnitrogenchloride was studied and the results are given
in the following tables. Conditions were the same as with
the acetylchloraminobenzene. In each case the constant was
calculated from the bimolecular equation. The two sets of
constants agree very well and show the rearrangement of the
paratolylacetylnitrogenchloride by one molecular quantity of
hydrobromic acid to be only about one-third as rapid as that
of the acetylchloraminobenzene.
Table XIII.
0.7 gram paratolylacetylnitrogenchloride in 30 cc. glacial
acetic acid and 270 cc. water at 5°; 2.65 cc. of 1.05 N HBr
(I mol.) added.
t.
Na2S2O8.
AK.
O
II.94
3.00
10.15
0.059
8.25
8.02
0.059
18.50
5.77
0.058
36.50
4.38
(0.047)
Average, 0.058
K, 0.098
Table XIV.
0.7 gram paratolylacetylnitrogenchloride in 30 cc. glacial
acetic acid and 270 cc. water at 5°; 2.69 cc. of 1.055 N HBr
I
(1 mol.) added.
t.
O
I.50
5.00
18.00
30.00
50.00
K, 0.098
Na2S2O3.
AK.
12.09
11.06
0.062
9.37
0.058
5.89
0.058
4.47
0.057
3.30
0.053
Average, 0.058
32
Rearrangement Experiments with Hydrochloric Acid.
The constant in each case is calculated from the monomo-
I
lecular equation (6) log
t
A
A-x
KCH. In the following
series of experiments with acetylchloraminobenzene and hydro-
chloric acid, the acid was added in amounts equivalent to those
of Blanksma¹ when he used 10, 15, 20, etc., cc. of 28.67 per cent
hydrochloric acid to 500 cc. of solution. I used the same
proportion of a different strength of acid to 250 cc. of solution.
Ten cc. of 28.67 per cent hydrochloric acid to 500 cc. solution
are taken as the standard and will be designated as M amount
of acid; others will be 2M, 3M, etc. Corrections were applied
for the difference in volume when the acid was added to the
standard solution of the acetylchloraminobenzene derivative
instead of making the entire solution standard as Blanksma
did. Tables XV. to XVIII., inclusive, show that the velocity
constant decreases with increasing per cent of water.
Tables XIX. and XX. show the relative reaction velocities
at 4° and 25°.
Tables XXI. to XXVII., inclusive, show the change of veloc-
ity of transformation with change in concentration of hydro-
chloric acid in 20 per cent acetic acid solution at 25°.
Tables XXVIII. to XXXIV., inclusive, show the change
of velocity of transformation with change in concentration of
hydrochloric acid in 30 per cent acetic acid solution at 25°.
Tables XXXV. and XXXVI. are a general resumé of Tables
XXI. to XXXIV., inclusive, and of Blanksma's work, showing
that the velocity of the transformation increases as the square
of the concentration of the hydrochloric acid. The change in
percentage of ionization of the hydrochloric acid with the small
changes in dilution used in these experiments is small and hardly
affects the values of the constant.
Tables XXXVII. to XLIII., inclusive, are a miscellaneous
set showing the velocity of transformation of acetylchlor-
aminobenzene by sulphuric acid and by acetic acid, and the
velocity of transformation of paratolylacetylnitrogenchloride
by hydrochloric acid.
33
The investigation will be continued.
Table XV.
2.0 grams acetylchloraminobenzene in 180 cc. glacial acetic
acid and 120 cc. water at 25°; 8.58 cc. of 5.49 N HCl (1.2 mol.)
added.
t.
O
5
ΙΟ
Na2S2O3.
43.19
27.32
16.32
9.43
5.56
30
2.02
15
20
K.
0.029
0.031
0.033
0.033
0.033
Average, 0.032
Table XVI.
1.0 gram acetylchloraminobenzene dissolved in 120 cc. glacial
acetic acid and 180 cc. water at 25°; 7.16 cc. of 5.49 Ñ HC1
(1 mol.) added.
t.
O
K.
Na2S2O3.
18.65
15
15.38
0.0057
30
12.68
0.0057
60
8.84
0.0057
75
7.24
0.0055
95
5.82
0.0055
120
4.32
0.0054
160
2.62
0.0054
Average, 0.0055
Table XVII.
1.0 gram acetylchloraminobenzene in 90 cc. glacial acetic
acid and 210 cc. water at 25°; 7.16 cc. of 5.49 N HCl (1 mol.)
added.
t.
Na2S2O3.
18.68
K.
60
II.00
0.0038
95
8.25
0.0037
120
6.83
0.0036
150
5.37
0.0036
180
4.46
0.0035
Average, 0.0036
34
Table XVIII.
1.0 gram acetylchloraminobenzene in 60 cc. glacial acetic
acid and 240 cc. water at 25°; 7.16 cc. of 5.49 N HCl (1 mol.)
added.
t.
Na2S2O3.
K.
O
17.92
63
12.63
0.0024
120
9.50
0.0023
180
7.21
0.0022
240
5.63
0.0021
300
4.48
0.0020
Average, 0.0022
The two following tables are given to show the temperature
coefficient for the reaction at 4° and at 25°. The velocity of
transformation is about 3.5 times as great at 25° as at 4°.
Table XIX.
1.10 grams acetylchloraminobenzene in 30 cc. glacial acetic
acid and 270 cc. water at 4°; 1.5 cc. of 6.59 N HCl added.
1.
O
Na2S2O3.
15.60
61
15.38
232
15.29
482
15.02
1140
14.50
1663
14.06
B.
(0.00010)
0.000038
0.000035
0.000027
0.000027
Average, 0.000032
Table XX.
1.0 gram acetylchloraminobenzene in 30 cc. glacial acetic
acid and 270 cc. water at 25°; 1.5 cc. of 6.59 N HCl added.
t.
Na2S2O3.
K.
O
16.17
120
15.62
0.00012
270
15.01
0.00012
438
14.34
0.00012
600
13.94
0.00011
1280
13.01
0.00007
1783
10.62
0.00010
Average, 0.00011
35
The following sets of tables show the variation in the ve-
locity constants with variations in the concentration of the
hydrochloric acid when the concentration of the acetylchlor-
aminobenzene is approximately the same in all the experiments.
Table XXI.
1.0 gram acetylchloraminobenzene in 60 cc. glacial acetic
acid and 237.44 cc. water at 25°; 2.56 cc. of 7.68 N HCl
(0.5 mol.) added.
t.
Na2S2O3.
K.
O
13.44
60
12.30
0.00064
150
10.72
0.00065
240
9.27
0.00067
390
7.44
0.00066
580
6.10
0.00060
Average, 0.00064
Table XXII.
1.0 gram acetylchloraminobenzene in 60 cc. glacial acetic
acid and 240 cc. water at 25°; 7.16 cc. of 5.49 N HCl (1 mol.)
added.
t.
Na2S2O3.
O
17.92
63
12.63
120
9.50
180
7.21
240
5.63
300
4.48,
K.
0.0024
0.0023
0.0022
0.0021
0.0020
Average, 0.0022
36
Table XXIII.
1.0 gram acetylchloraminobenzene in 60 cc. glacial acetic
acid and 240 cc. water at 25°; 10.74 cc. of 5.49 N HCl (1.5 mol.)
added.
3
t.
K.
Na2S2O3.
O
30
60
22.12
17.31
(0.0036)
7
12.34
0.0042
90
9.17
0.0043
120
6.88
0.0042
150
5.24
0.0041
180
4.14
0.0041
Average, 0.0041
Table XXIV.
1.0 gram acetylchloraminobenzene in 60 cc. glacial acetic
acid and 240 cc. water at 25°; 14.49 cc. of 5.45 N HCl ( 2 mol.)
added.
t.
Na2S2O3.
K.
21.05
30
13.66
0.0067
45
10.78
0.0068
60
8.39
0.0071
75
6.62
0.0072
90
5.34
0.0068
Average, 0.0069
Table XXV.
1.0 gram acetylchloraminobenzene in 60 cc. glacial acetic
acid and 221.86 cc. water at 25°; 18.16 cc. of 5.45 N HCl
(2.5 mol.) added.
t.
O
ΙΟ
Na2S2O3.
22.26
16.38
K.
0.0133
20
12.30
0.0126
30
40
9.14
6.94
0.0129
0.0127
50
5.30
0.0125
Average, 0:0128
37
Table XXVI.
1.0 gram acetylchloraminobenzene in 60 cc. glacial acetic
acid and 218.2 cc. water at 25°; 21.80 cc. of 5.45 N HCl (3 mol.)
added.
t.
Na2S2O3.
K.
O
22.52
5
17.81
0.0204
IO
14.08
0.0204
15
II.23
0.0202
25
7.16
0.0199
?
40
3.74
0.0195
Average,
0.0201
Table XXVII.
1.0 gram acetylchloraminobenzene in 60 cc. glacial acetic
acid and 213.4 cc. water at 25°; 26.6 cc. of 7.68 N HCl (5 mol.)
added.
t.
Na2S2O3.
K.
936
16.13
9.96
0.0698
6.36
0.0674
9
3.93
0.0681
15
1.68
0.0655
21
1.82
0.0616
Average, 0.0663
Table XXVIII.
1.0 gram acetylchloraminobenzene in 90 cc. glacial acetic
acid and 207.44 cc. water at 25°; 2.56 cc. of 7.68 N HCl
(0.5 mol.) added.
t.
O
Na2S2O3.
15.20
60
12.22
120
210
II.49
9.25
330
6.92
480
4.76
K.
(0.0016)
0.00IOI
0.00102
0.00103
0.00105
Average, 0.00103
38
Table XXIX.
1.0 gram acetylchloraminobenzene in 90 cc. glacial acetic
acid and 210 cc. water at 25°; 7.16 cc. of 5.49 N HCl (1 mol.).
added.
t.
Na2S2O3.
K.
O
18.68
60
II.00
0.0038
95
8.25
0.0037
120
6.83
0.0036
150
5.37
0.0036
180
4.46
0.0035
Average, 0.0036
Table XXX.
1.0 gram acetylchloraminobenzene in 90 cc. glacial acetic
acid and 202.32 cc. water at 25°; 7.68 cc. of 7.68 N HCl
(1.5 mol.) added.
t.
་
K.
Na2S2O3.
O
18.15
15
13.42
0.0087
30
9.99
0.0086
45
7.42
0.0087
60
5.52
0.0086
75
4.18
0.0085
Average, 0.0086
Table XXXI.
1.0 gram acetylchloraminobenzene in 90 cc. glacial acetic
acid and 195.47 cc. water at 25°; 14.53 cc. of 5.45 N HCl (2 mol.)
added.
t.
Na2S2O3.
K.
O
22.72
IO
16.23
0.0146
20
II.57
0.0147
30
8.22
0.0147
55
3.61
0.0145
80
1.73
0.0148
Average, 0.0146
39
Table XXXII.
1.0 gram acetylchloraminobenzene in 90 cc. glacial acetic
acid and 197.2 cc. water at 25°; 12.80 cc. of 7.68 N HCl (2.5
mol.) added.
t.
Na2S2O3.
K.
O
17.10
5
13.02
0.0277
IO
9.97
0.0234
15
7.72
0.0230
20
5.90
0.0231
30
3.60
0.0226
Average, 0.024
Table XXXIII.
1.0 gram acetylchloraminobenzene in 90 cc. glacial acetic
acid and 194.64 cc. water at 25°; 15.36 cc. of 7.68 N HCl
(3 mol.) added.
t.
Na2S2O3.
K.
O
17.19
3
13.90
0.0307
7
IO.34
0.0315
II
7.78
0.0313
15
5.80
0.0315
19
4.32
0.0316
Average, 0.0313
Table XXXIV.
1.0 gram acetylchloraminobenzene in 90 cc. glacial acetic
acid and 184.4 cc. water at 25°; 25.6 cc. of 7.68 N HCl (5 mol.)
added.
t.
Na,S₂Og.
K.
O
2
17.95
10.42
0.118
4
6.16
0.116
6
3.73
0.114
8
2.29
0.112
12
0.92
0.108
Average, 0.114
40
Summary.
The two following tables give a summary of the preceding
ones and of Blanksma's work. Ordinary logarithms were
used instead of the natural system. The list under "glacial
acetic acid" gives the volume per cent of acetic acid used in
the solution. The table under HCl gives the concentrations
of the hydrochloric acid, calculated as explained above. The
constants in parenthesis are the values calculated from the
average constant. It will be noticed that the agreement be-
tween the calculated and found values is very good. Blanks-
ma's table shows that an increase of 10 per cent in the concen-
tration of the acetic acid causes approximately a doubling
of the constants.
4I
Table XXXV.
HC1.
Glacial acetic acid.
20 per cent
30 per cent
40 per cent
60 per cent
0.5 M.
0.00065
I M.
0.0022
1.5 M.
2 M.
0.0070
2.5 M.
0.0128
3 M.
0.0201
5 M.
0.0041
0.0663
(0.00056) (0.0021) (0.0048) (0.0086) (0.0133) (0.0199) (0.0539)
0.00103 0.0036 0.0087 0.0146 0.0239 0.0313
(0.00098) (0.0039) (0.0087) (0.0154) (0.0242) (0.0348)
0.0556
0.033
0.113
(0.097)
42
Table XXXVI. (Blanksma's).
HCl.
Glacial acetic acid.
20 per cent
IO CC.
15 cc.
20 CC.
25 cc.
0.00218
0.00419
0.00814
30
0.00364 0.00802
0.0137
0.0104
0.0198
(6
40
0.00676
0.0144
0.0253
50
60
0.0155
0.0309
(6
0.036
Table XXXVII.
The effect of the suppression of ionization was studied.
1.0 gram acetylchloraminobenzene in 60 cc. glacial acetic
acid and 227.2 cc. water at 25°; 4.4 grams of KCl (10 mol.)
and 12.80 cc. of 7.68 N HCl (2.5 mol.) added. The effect
was to increase greatly the velocity of reaction.
t.'
Na2S2O3.
K.
O
16.83
IO
10.84
0.0191
20
6.88
0.0194
30
4.50
0.0191
40
2.92
0.0190
50
1.84
0.0192
Average, 0.0192
Table XXXVIII.
KCl alone causes very little change. I gram acetylchlor-
aminobenzene in 60 cc. glacial acetic acid and 240 cc. water at
25°; 4.4 grams KCl (10 mol.) added.
t.
Na2S2O3.
K.
O
16.02
30
15.74
(0.00025)
90
15.64
0.00012
185
15.08
0.00014
300
14.65
0.00013
420
14.00
0.00014
Average, 0.00013
43
Table XXXIX.
Glacial acetic acid alone causes very little rearrangement;
1 gram acetylchloraminobenzene in 90 cc. glacial acetic acid
and 210 cc. water at 25°.
K.
Na2S2O3.
O
16.70
120
16.63
0.000015
360
16.54
0.000012
1380
16.45
0.0000048
1900
16.41
0.0000040
2935
16.37
0.0000029
Table XL.
Rearrangement experiment with sulphuric acid; 1.1 grams
acetylchloraminobenzene in 30 cc. glacial acetic acid and 270 cc.
water at 4°; 5.3 cc. of N H₂SO, added.
t.
O
4
36
K.
0.0028
Na2S2O3.
21.37
20.82
20.75
0.00036
103
19.93
0.00029
960
17.01
0.00010
4115
15.88
0.000031
8190
13.26
0.000025
?
1
Table XLI.
0.7 gram paratolylacetylnitrogenchloride in 30 cc. glacial
acetic acid and 270 cc. water at 3°; 2.50 cc. of 6.59 N HCl
(5 mol.) added.
t.
O
Na2S2O3.
14.19
28.12
13.63
58.50
13.10
120.75
12.18
289.87
420.00
9.47
7.56
•
K.
0.00062
0.00059
0.00055
0.00061
0.00065
Average, 0.00061
44
Table XLII.
0.7 gram paratolylacetylnitrogenchloride in 30 cc. glacial
acetic acid and 260 cc. water at 3.5°; 7.82 cc. of 6.59 N HCl
(20 mol.) added.
t.
0
Na2S2O3.
K.
II.25
16.5
II.05
(0.00092)
45
10.96
0.00025
90
10.67
0.00025
150
10.19
0.00028
300
7.96
0.00030
Average, 0.00027
Table XLIII.
0.6 gram paratolylacetylnitrogenchloride in 30 cc. glacial
acetic acid and 260 cc. water at 3°; 7.82 cc. of 5.49 N HCl
(20 mol.) added.
t.
Na2S2O3.
K.
O
9.32
90
150
360
888
30
9.05
(0.00043)
60
8.98
0.00027
8.80
0.00028
8.42
0.00029
7.14
0.00032
Average, 0.00029
While Tables XLII. and XLIII. agree very well, they do not
harmonize with Table XLI. and the general results obtained
above. In Tables XLI., XLII. and XLIII. the concentration
of the hydrochloric acid used was calculated from the concen-
tration of the paratolylacetylnitrogenchloride.
GENERAL DISCUSSION OF THE HYDROLYSIS OF AMIDES, CANE-
SUGAR, OXIMES AND ESTERS.
In the hydrolysis of esters, cane-sugar, amides, amidines,
nitriles, oximes and related compounds we are dealing with
weak bases in the presence of acids and water. Many salts
of these weak bases, amides, nitriles, esters and oximes, have
been isolated and studied. The affinity constant for acet-
45
7
4
9
amide,¹ for instance, is 3 X 10-15 at 25°, and that for pro-
pionitrile at the same temperature is 1.8 X 10-15. The work
of Collie and Tickle,2 Baeyer and Villiger,³ Werner, Brühl,5
Archibald and McIntosh," Walden, van't Hoffs and many
others leaves no doubt that esters, ketones alcohols, sugars,
ethers, and organic acids are weak bases and form tetravalent
oxygen salts which are derivatives of the hypothetical ox-
onium hydroxide, H,OOH. The work of Sackur, Kablu-
koff,10 Coehn,11 Walden,12 Baeyer and Villiger, Collie and
Tickle, Archibald and McIntosh and Walker13 have shown
conclusively that these salts are electrolytes, in which the
tetravalent oxygen compound probably forms part of the cathion.
The affinity constant of dimethylpyrone as a base, for instance,
was found to be about 2.4 X 10-14. In cane-sugar, ethers,
and similar compounds we have a COC linkage, which can
H
form salts, coc.
form salts, COC. There is plenty of evidence to show that
C1
all these compounds have both basic and acid properties.
Now the work of Arrhenius,¹¹ of Walker15 and of Shields¹6
has shown that when these weak bases are treated with acids
a small amount of salt is formed according to the following
equation:
Κω
Csalt dis,
(1)
(Csub-x) X CH
Khyd Csalt dis
Ko
¹ Z. physik. Chem., 4, 319. Ahren's Sammlung, Abegg, 8, 183.
2 J. Chem. Soc., 75, 710.
8 Ber. d. chem. Ges., 34, 2692; 35, 1201.
* Ann. Chem. (Liebig), 322, 296. Ber. d. chem. Ges., 34, 3300.
5 Ibid., 28, 2847, 2866. Z. physik. Chem., 18, 514.
• Ibid., 55, 129. Phil. Trans., 205, 99. J. Chem. Soc., 85, 919.
7 Ber. d. chem Ges., 34, 4185.
8 Ansichten uber die Organische Chemie, I Theil, p. 62, fol.
9 Ber. d. chem. Ges., 35, 1242.
10 Z. physik. Chem., 4, 429.
11 Ber. d. chem. Ges., 35, 2673.
12 Ibid., 34, 4185; 35, 1764.
18 J. Chem. Soc., 85, 1098. Ber. d. chem. Ges., 34, 4115.
14 Z. physik. Chem., 5, 1; 13, 407.
15 Ibid., 4, 319; 32, 137; J. Chem. Soc., 77, 5.
16 Z. physik. Chem., 12, 167.
46
in which, Csub is the original concentration of the base in gram
molecules per liter, x the amount of base transformed into
the other products at any moment, (Csub x) the concen-
tration of the base at any moment, C that of the hydrogen
ions, Csalt dis that of the dissociated portion of the salt,
practically all ionized, Kyd the hydrolysis constant, K, the
affinity constant of the base and K, the ion product for water
at the given temperature. But the amount of salt, Csali dis'
present in such cases is extremely small and for (Csub-x)
and CH we may substitute, without appreciable error,
the values they would have if no salt were formed. In those
cases in which Csalt dis is large this cannot be done, but the
concentrations of each substance can be determined from (1).
It is the opinion of a large number of chemists that the
above salts are intermediate compounds in the catalytic trans-
formations spoken of, and that such catalytic reactions are
brought about solely because of, and through, the formation
of such intermediate compounds.
The work of Remsen and Reid¹ on the hydrolysis of amides
by acids, and of Acree and Johnson² from theoretical grounds,
indicated an intermediate formation of an amide salt, the
cathion of which reacts with water and forms an acid and the
ammonium ion, just as the urazole ion reacts with the neutral
ethyl iodide.
CH,CONH,+H+C+HO
+
CH₂COÑ͸ + H₂O + Cl
3
3
CH,COOH +NH, +C1.
4
This idea is fully verified by the work of Mr. Sidney
Nirdlinger in this laboratory and by all the data of Ost-
wald. Julius Stieglitz has further verified this by work
on the hydrolysis of imido esters in the presence of acids,
in that he showed that the imido ester cathion is hydrolyzed:
Am. Chem. J., 21, 281; Reid: Ibid., 24, 397.
Ibid., 37, 410.
• Congress of Arts and Science, St. Louis, 1904, 4, 276.
47
CH,C(NH)OC₂H + H+ С1 + H₂O
+
CH¸C(ÑH₂)OC₂H¸ + H₂O + Cl
5
+
C,HCOOC,H. + NH, + Cl.
Lapworth¹ and then Bredig and Stern' showed that cyan-
ides act catalytically in causing such condensations as the
formation of benzoin from benzaldehyde, solely because the
cyanide ion unites with benzaldehyde and forms a complex
anion which reacts with benzaldehyde and yields benzoin and
a cyanide ion.
+
2CH,CHO + K+CN
+
C₂H,CH(CN)O + K + C,н¸CHO
C.H,CHOHCOCH, +K+CN.
Bredigs and Euler suggested that acids cause the catalytic
inversion of cane-sugar in water solutions, and of diazoacetic
ester and other esters in water because the hydrogen ions
unite with the weak bases, sugar and esters, and form salts
which are hydrolyzed by the water.
+
(C¸H1105)₂O + H + Cl + H₂O
→→→
+
2С。H12O8 + H + Cl.
Luther and Sammet have shown that the equilibrum be-
tween iodic acid, hydriodic acid, iodine and water is between
the hydrogen, iodide and iodate ions on the one hand and
iodine and water on the other and can be expressed by the equa-
tion
J. Chem. Soc., 83, 995.
2 Z. Elek. Chem., 10, 585.
³ Ibid., 9, 118; 10, 586; 11, 528.
4 Z. physik. Chem., 36, 405, 663; 40, 501; 47, 356.
5 Z. Elek. Chem., 11, 293.
48
+
(H)°(IŌ₂)(I)°
(12) 3
5
6
2.8(±0.3) X 10-47.
8
3
Finally, Bredig, Euler,¹ Abegg,2 Goldschmidt, Wegscheider,¹
Zengelis,5 Lapworth, Kastle," Stieglitz, and Acree and
Johnson⁹ have discussed the saponification of esters and for-
mation of esters from the point of view that intermediate ions
are the substances transformed. Lapworth, Bredig, Euler,
Stieglitz, and Acree and Johnson have believed that an ap-
plication of the mass law harmonizes with the idea that esters
may be saponified by water in the presence of acids because
of the intermediate formation of an ester cathion which is
hydrolyzed,
+
CH,COOR + H + Cl + H₂O →
+
CH,COOR.H + H₂O + Cl
+
CH,COOH + ROH + H + Cl,
and Acree and Johnson¹º have shown from theoretical grounds,
that the undissociated ester salt is not the substance which
chiefly is hydrolyzed.
If now, in the catalysis of cane-sugar, esters, etc., we have,
in general, an intermediate salt formation and a direct hydrol-
ysis of complex ion, the velocity of transformation of the cane-
sugar must be dependent upon the concentrations of the com-
plex ion and the water, or
-dCsub cathion
dt
dx
Ktrans Csub cathion X CH₂O, (2)
dt
¹ Z. physik. Chem., 36, 405, 663; 40, 501; 47, 356.
Z. Elek. Chem., 10, 185.
Ibid., 10, 221.
• Z. physik. Chem., 39, 257; 41, 62.
Ber. d. chem. Ges., 34, 198.
3 See Mellor's "Chemical Statics and Dynamics," 1904, p. 289.
7 Private communication. Am. Chem. J., 19, 894. P. Am. Assn. Adv. Sci., 47, 238.
8 Loc. cit.
9 Am. Chem. J., 37, 410.
10 Loc. cit.
49
sub cathion'
in which -dC,
or dx, is the small amount of Csub cathion
hydrolyzed in the time dt, CHO is the original concen-
tration of the water, and x the amount of water which
has been used up in the reaction at the time under con-
sideration. The small amount —dC
sub cathion changed in dt is
exactly equal in gram equivalents to the small amount dx
of sugar and of water changed in the same time interval. We
may, therefore, consider these two equivalent in all of the
cases under consideration and write dx for the small amount
of substance transformed whether it be the intermediate
compound or the sugar, ester, etc. The dx represents an in-
crease, whereas —dC sub cathion represents a decrease; hence the
one is the negative of the other.
In the total reaction, expressed by equations (1) and (2), we
are dealing with two consecutive reactions. The first is a rever-
sible reaction involving what may be considered, for practical
purposes, a bimolecular and a unimolecular reaction. The second
is a practically non-reversible bimolecular reaction. Now the
concentration of Csub cathion
at any moment depends upon
the concentrations of the sugar, hydrogen ions, anions, and
water, at the moment and upon the velocities of the first and
second reactions. Now the first reaction is the neutraliza-
tion of a base by an acid, and all such reactions take place,
as a rule, immeasurably rapidly. The second reaction is
therefore very slow in comparison with the first, and the equilib-
rium expressed in equation (1) is never appreciably disturbed
by the change in the concentration of C
in reaction (2).
It is evident then, from (1), that we can substitute
+
sub cathion
K₂
Kw
(Csub-x) × CH
for Csub cathion in (2) and
in (2) and we then get
dx
dt
Ktrans
Kb (Csub-x) X CH× (CH₂0—x). (3)
Kw
But this is exactly the relation found experimentally for the
hydrolysis of amides, inversion of cane-sugar and the saponi-
fication of esters. It is evident, then, that intermediate sugar
50
cathions, ester cathions, amide cathions, etc., may be the
substances chiefly undergoing hydrolysis.
But Acree and Johnson¹ have shown, further, that the un-
dissociated sugar salt, ester salt, or amide salt is certainly not
the substance chiefly undergoing hydrolysis.
If such were the case the velocity of transformation of the
sugar, ester or amide would be proportional to the concentra-
tions of the undissociated salt and the water, or
-dCsalt und
dt
dx
dt
Ktrans Csalt und × (CH₂0 — x). (4)
But the undissociated salt is in equilibrium with its ions and
Csalt dis X Ca
Kaffin Csalt und.
(5)
By substituting in (4) the value of Csalt und derived from
(1) and (5) under the same conditions discussed above for the
sugar cathions, we derive
dx
Ktrans Kb
(Csub-x) X CH X Ca X (CH₂0-x)=
dt
Kaffin Kw
(6)
K(Csub — x) × CH × (CH₂0—x).
But equation (6) does not correspond to the facts found ex-
perimentally. The velocity of saponification of esters, amides
and cane-sugar is not proportional to the square of the concen-
tration of the hydrogen ions, but simply to the concentration.
Since in a water solution of the weak bases, cane-sugar, esters
amides, oximes and acids there are present (1) the free base,
that is, the sugar, ester, etc.; (2) the undissociated salt; and
(3) the dissociated salt; one of these three must be the sub-
stance hydrolyzed. Since the free base, that is, the cane-sugar
etc., and the undissociated salt are not chiefly concerned in the
hydrolysis, it is evident that the substance undergoing hy-
drolysis must be the complex cathion formed by the union of
hydrogen ions with cane-sugar, esters amides, oximes, etc.
The equations worked out above are not exact, but the errors
involved in using them are probably within the limits of ex-
periment. An exact application of the mass law would lead
¹ Loc. cit.
}
51
to very complex equations which would hardly lend themselves
to a practical solution of the problem with the data now at
hand.
We are now in a position to discuss the evidence bearing on
each of the above catalytic reactions.
ON THE INVERSION OF CANE-SUGAR IN AQUEOUS SOLUTIONS OF
ACIDS.
4
Ostwald,¹ Cohen,2 Smith,³ Wilhelmy, Arrhenius,5 Uhrech,º
Spohr and Trevors have shown that aqueous solutions of
cane-sugar are hardly affected by pure water, but inversion
of the sugar takes place upon the addition of acids, although
the acid is not used up in the reaction.
The velocity of inversion by acids, or by water, is almost
exactly proportional, in dilute solutions, to the concentration
of the hydrogen ions, and is expressed by the equation
dx
dt
K(Csugar —x) × (CH₂0-x) × CH. (1)
In dilute solutions, since CH and (Cн₂0¯x) are approximately
constant the reaction is, apparently, one of the first order.
In more concentrated solutions, since the factor (CH₂0-x)
changes appreciably in value, the reaction proves to be one of the
second order. Now cane-sugar has the same "ether" linkage,
COC, common to a large number of oxygen compounds which
have been shown to have basic properties, and it might be ex-
pected to form tetravalent oxygen salts of the same general
type, R₂O.HCI.
Unfortunately, cane-sugar is not soluble in the solvents
from which we could expect to precipitate its hydrochloride.
But Hantzsch has shown that cane-sugar, just as dimethyl-
1 J. prakt. Chem. [2], 29, 385; [2], 31, 307.
• Z. physik. Chem., 28, 145.
'Ibid., 25, 144, 193.
♦ Pogg. Ann., 81, 413, 499.
5
Z. physik. Chem., 4, 226.
6 Ber. d. chem. Ges., 13, 1696; 15, 2130, 2457, 2687; 16, 762; 17, 47, 495, 2165 ;
18, 3047; 20, 1836; 22, 318.
7 J. prakt. Chem. [2], 32, 32; [2], 33, 265.
8 Z. physik. Chem., 10, 321.
9 Ber. d. chem. Ges., 38, 2143.
52
pyrone, glucose and other weak bases, lowers to a small ex-
tent the conductivity of sulphuric and hydrochloric acid solu-
tions. Dulcite¹ forms a hydrochloride, a hydrobromide, and
a hydriodide which can be isolated.
Furthermore, sugars show their basic properties² in forming
complex salts, as Rosenheim³ has pointed out. We are,
therefore, justified in concluding that sugars do form a very
small amount of salt in acid solutions. Of course the cane-
sugar is such a weak base that these salts would be nearly
completely hydrolyzed.
The relation between the concentrations of the sugar, acid
and salt formed are expressed as follows:
+
Cl
(CHO),O+H+C1 (CH,O),OH+C
11
S
(CH110¸)₂O.HC1,
m
or
Κω
(Co—x) × CH = KhydC₁ = Kw C₁
and
Ko
(Co-x) X CHX CC
Kaffin Kw Cmy
Сто
Kh
(2)
in which C₂ represents the initial concentration of the sugar,
C, the concentration of the complex sugar cathion at the mo-
ment considered, and Cm that of the undissociated complex
sugar salt. The amount of sugar changed into salt is so small
that (C₂-x), CH and Cc have practically the value which they
would have if no salt were formed.
If, now, the complex sugar cathion is hydrolyzed by the
water according to the following equation, in which C, and
(CH₂O-x) represent
+
(CH„O̟¸)‚Ỗн + н,0 =>
11
+
12
2CH22O+ H,
or
¹ Bouchardat: Compt. rend., 74, 866. Ann. Chim. Phys. [4], 27, 145.
2 Peligot: Compt. rend., 7, 106. Ann. Chim. Phys. [2], 67, 113; Violette: Compt.
rend., 76, 485. Maumené: Bull. Soc. Chim. [2], 19, 289.
Ber. d. chem. Ges., 34, 3377; 35, 1115; 36, 1833; 37, 3662; 38, 2777.
53
-dCs
dx
KtransCs (CH₂0-x),
dt
dt
(3)
the concentration of the cathion and the water at any given
moment, it follows from (2) that we can substitute for Cs
the value
Кь
(C−x) X CH
Kw
and we then get
dx
dt
Ko
Kw
Ktrans (Co−x) X CH X (CH,O−x), (4)
which is actually what is found experimentally.
But if the undissociated salt were the substance undergoing
hydrolysis,
+
(CH₁₁₂)₂O.HCl + H₂O →→ 2C8H12O8+ H+ Cl
11
or
-dCm
dx
dt
Ktrans Cm X (CH₂O-x),
(5)
dt
it follows from (2) that we can substitute for Cm the value
Ko
KwKaffin
·(Co-x) X CH X CC,
and we then get
dx
dt
Ktrans Kb
(Co-x) X CHX CaX (CH₂0— x), (6)
Kw Kaffin
in which (C-x) is the concentration of the sugar at any
moment and (CH₂0-x) is that of the water.
x) is that of the water. In dilute solu-
tions, (CH₂o-x) hardly changes in value, and the reaction ap-
pears to be monomolecular.
But equation (6) does not express the quantitative relations
actually found to hold experimentally. It, therefore, follows
that the undissociated salt, Cm, cannot be the substance which
is chiefly undergoing hydrolysis, although it may do so to a
small extent.
54
114
We are then led back to the idea that (1) the amount of com-
plex cathion is directly proportional to the product of the con-
centrations of the sugar and of hydrogen ions, whether the
hydrogen ions came from strong acids, weak acids or water;
(2) the velocity of inversion of cane-sugar is also proportional-
to the product of the concentrations of the sugar and of the
hydrogen ions. It is, therefore, possible, and from the above
evidence probable, that cane-sugar is inverted or hydrolyzed
in aqueous solutions containing hydrogen ions because the
hydrogen ions first unite with the sugar and form a com-
plex cathion which is then decomposed by the water into glu-
cose, fructose and hydrogen ions.
Exactly analogous to the inversion of cane-sugar and other
sugars is the hydrolysis of the diethylacetal of glyceric alde-
hyde,¹
1
CH₂OHCHOHCH(OC₂HÁ)2,
a-methylglucoside,2
H
CH₂OHCHOHCH(CHOH),COCH3,
O
and other similar compounds by dilute aqueous solutions of
acids. These substances are not hydrolyzed in alkaline solu-
tions. In all of these cases the "ether linkage" seems to be
the point of attack. This would be expected if intermediate
salt formation takes place and is followed by hydrolysis, as
discussed above:
H
+
CH₂OHCHOHCH(CHOH),COCH, + H+ Cl + H₂O
H +
H
CH₂OHCHOHCH(CHOH),C—OCH₂ + Cl + H₂O =→
Wohl: Ber. d. chem. Ges., 31, 1796.
2 Fischer: Ibid., 26, 2400; 27, 2478.
55
H
CH₂OHCHOHCH(CHOH),—C—OH + H+ Cl + CH₂OH.
ó
ON THE REACTIONS OF CARBONYL COMPOUNDS WITH HYDROXYL-
AMINE AND WITH HYDROXYLAMINE HYDROCHLORIDE.
Theoretical.
Ketones and aldehydes react with hydroxylamine and form
oximes. Nothing has been known up to this time of the ra-
pidity or order of the reaction of various carbonyl compounds
with the hydroxylamine. In Victor Meyer's¹ directions for
making acetoxime from acetone and hydroxylamine, the
mixture stood over night. I have found, however, that the
reaction is practically finished in a few minutes at 100° and in
2 hours at 65°. The reaction is approximately one of the sec-
ond order. Although the reaction certainly goes nearly to
completion, it seems to be reversible.
(CH,),CO + NH, OH
(CH₂),C: NOH + H₂O
(1)
Since diethyl ketone reacts more slowly, and acetaldehyde
more rapidly, with hydroxylamine than does acetone, it is
probable that the so-called space interference influences these
reactions. The velocity constant for the reaction between
acetaldehyde and hydroxylamine in o.1 N solutions at 10°.5
is 0.035. The constant for o.1 N acetone and o.1 N hydroxyl-
amine at 1° is 0.0040, while at 65° it is o°.060. The constant
for o.1 N diethylketone and o.1 N hydroxylamine at 35° is
0.005, while at 65° it is 0.010. These constants are calculated
on the assumption that the reaction goes to completion. This
is probably not true, as the reaction seems to be reversible;
but the reaction goes so nearly to completion that only a small
error is involved in the assumption made above.
When hydrochloric or hydrobromic acid is added to a mix-
ture of acetone and hydroxylamine, the reaction progresses far
more rapidly, just as is the case in ester catalysis, cane-sugar,
1 Ber. d. chem. Ges., 15, 1324.
56
inversion, etc. This at once makes us suspect that the hydro-
chloric acid acts as a catalytic agent because it acts upon the
base hydroxylamine and produces a greater concentration
of the hydroxylammonium ions, which then react more rapidly
with the acetone.
+
(CH₂)₂CO + NH₂OH + H+ Cl
+
(CH3)2CO + NH₂OH + Cl
+
→
(CH¸),C(OH)ÑH,OH + Cl →
+
(CH3)2C : NOH + Cl + H₂O
H
+
(CH3)2C : NOH + H + Cl + H₂O (2)
Strangely enough, however, when hydrochloric acid is ad-
ded to accelerate the reaction the process does not go to com-
pletion as it practically does when no acid is present. The
reason for this is now clear. In the presence of hydrochloric
acid acetoxime is partly hydrolyzed into acetone and hydroxyl-
amine hydrochloride. Janny's¹ statement that acetoxime is
completely hydrolyzed by hydrochloric acid, and similar
statements in text-books, are erroneous. I have found that
a large excess of acid is not sufficient to hydrolyze the acetox-
ime completely. In fact there is always an equilibrium es-
tablished and the equilibrium point is the same whether acet-
oxime is treated with a given amount of hydrochloric acid
at a given temperature, or the equivalent quantities of ace-
tone, hydroxylamine and hydrochloric acid are brought to-
gether under the same conditions.
Especially important, however, is the fact that a change
in the amount of hydrochloric acid effects a change in the equi-
librium in the system expressed in the following equation:
+
(CH₂),C : NOH + H+ C1 + H₂O
+
(CH¸),C : ÑHOH + H₂O + C1
+
(CH3)2Cон NH₂OH + C1
+
(CH,),CO +NH,OH+C1 (3)
1 Ber. d. chem. Ges., 16, 170.
57
8
The water is probably added to the double bond in all such re-
actions before the products of hydrolysis are formed. It
has been found that an increase in the amount of hydro-
chloric acid causes a very decided increase in the amount of
hydroxylamine hydrochloride, although the addition of sev-
eral molecules of hydrochloric acid does not cause complete
hydrolysis of the acetoxime. This is a very important case
and probably, with the one of Bauer and Voermann,¹ is the
confirmation of the ideas advanced by Acree and Johnson,2
that in some reversible reactions it will be found that a change in
the concentration of the catalyzer will produce a change in
the equilibrium of the system. That there is a real change
in the equilibrium was shown quite definitely by the fact that
the same equilibrium point is established whether the acid
be added to acetoxime in solution or to the equivalent concen-
trations of acetone and hydroxylamine. The cause of this
change in equilibrium is probably the following. The acet-
oxime is a very weak base, as has been established by Walker.
There is, however, an error in Walker's work, due to the fact
that he did not take into consideration the hydrolysis of the
acetoxime and the formation of hydroxylamine hydrochloride
which is far less hydrolyzed than the acetoxime. The acetox-
ime is a very weak base and its hydrochloride is greatly hy-
drolyzed in water solution. I have been able to show this
by the simple process of titrating 0.1243 gram acetoxime in
10 cc. water containing methyl orange with o.1 N hydrochloric
acid; it requires only 0.25 cc. of the total molecular quantity,
17.00 cc., to give the solution a pink color. In the solution
of the acetoxime and hydrochloric acid there can be only
a small amount of the acetoxime cathion, which could be
calculated if the affinity constant of the base were known.
If the data in the experimental portion were a little more
accurate they could be used to determine the affinity constant
of the acetoxime. The small amount of acetoxime cathion
is almost surely the substance in equilibrium with the hydroxyl-
ammonium ion and acetone as follows:
1 Z. physik. Chem., 52, 467.
2 Am. Chem. J., 37, 410.
8 Z. physik. Chem., 4, 330.
}
58
+
(CH3)2C : NHOH + H₂O
+
(CH¸)₂CO + Ñ͸OH.
But the hydroxylamine is such a strong base that its hydro-
chloride is practically not hydrolyzed at all and reacts only
faintly acid to methyl orange. The addition of more hydro-
chloric acid then causes the formation of more acetoxime
cathion from the acetoxime then present, but does not change
appreciably the concentration of the hydroxylammonium
ions then present. Since this acetoxime cathion formed must
change to conform to the equilibrium expressed above, more
acetone and more hydroxylammonium ions must be formed
from the acetoxime cathion and water to restore the equi-
librium. Since the hydroxylammonium ion is not appreciably
changed into hydrogen ions and hydroxylamine, the change
in equilibrium is accompanied by disappearance of the hydro-
gen ions. Of course the real equilibrium between the acetoxime
cathion and the acetone and hydroxylammonium ion is not
changed, but the apparent equilibrium between the acetone,
total hydroxylamine, salt, and total acetoxime and salt is
changed.
The fact that the equilibrium is changed in Tables XXIX.
to XLII. by change in concentration of the acid is of very great
importance in the theory of the catalytic influence of acids
on reversible reactions. Practically the only well-known
reversible reaction influenced catalytically by hydrogen ions
is the reversible reaction between organic acids and alcohols
on the one hand and esters and water on the other. In
this reaction the equilibrium is not disturbed appreciably by
change in the concentration of the hydrogen ions. The reason
for this is that little of the hydrogen ions unites with either or-
ganic acid or ester, whereas in the work quoted above on the
saponification of the oxime, nearly all of the hydroxylamine
exists in the form of cathions. This subject will be treated
in detail in the section dealing with esterification and
saponification.
Furthermore, the very interesting fact was established that
the equilibrium in a given system changes with temperature.
A rise in temperature from 10°.5 to 92° produces a gradual
59
increase in the amount of hydroxylamine hydrochloride and
acetone necessary for equilibrium with the acetoxime hydro-
chloride, the equilibrium at the higher temperatures being
established very quickly. A decrease in temperature brings
about the reverse process, and the same equilibrium is found
at a given temperature as was established when the temper-
ature was rising. It is very probable that the decided appar-
ent increase with rise in temperature in the affinity constant
of acetoxime recorded by Walker is due to the above causes.
With rise in temperature there is an increase in the amount of
the hydroxylamine and its hydrochloride. Since hydroxyl-
amine is a much stronger base than acetoxime, a greater per-
centage of the hydrogen ions disappear in the formation of
hydroxylammonium ions at the higher temperature, and hence
the acetoxime seemed to Walker to be a stronger base than
it really is. The point is that at the higher temperature
the hydrogen ions do not disappear in the formation of acetox-
ime cathion, but in the formation of hydroxylammonium ions.
The change in equilibrium with change in temperature may
be the result of exothermic or endothermic reactions, or change
in the affinity constant of the bases with change in tempera-
ture, or may come from other causes, which can only be de-
termined by further work.
That there is really equilibrium between the acetone and
hydroxylammonium ions on the one hand and the acetoxime
cathions on the other in a solution of these substances is shown
further by the fact that the addition of acetone to the solu-
tion causes a decrease in the amount of hydroxylamine hy-
drochloride, whereas the addition of hydrochloric acid causes
an increase in the concentration of the hydroxylamine hy-
drochloride and its ions. If equation (3) really represents
the reaction we can express the equilibrium condition by equa-
tion (4),
Cacetone X Chydam
Cacoxcat
=
= K,
(4)
in which Cacetone Chydam and Cacoxcat represent the concen-
trations of the acetone, hydroxylammonium ions and acetox-
60
ime cathions, respectively. Now the concentrations of the
acetone, hydroxylamine ions and total acetoxime and its salt
can be determined analytically at any moment by the above
method. But the value of Cacoxcat can not be determined
accurately by the analytical method employed in the present
communication. A very close approximation can be made
to it, however, when the concentrations of the acetone, hy-
droxylamine and hydrochloric acid have somewhere near the
same values.
Since the acetoxime is a very weak base, the value of
Cacoxcat in the equilibrium equation,
+
(CH,),C = ÑHOH
+
(CH₁)C = NOH + H
Cacoxcat
Cacox X CH
=
K',
(5)
is a very small part, probably only about 5 per cent of the
value of Cacox, the concentration of the free base acetoxime.
Instead of Cacoxcat in equation (4) we can substitute
K' Cacox X CH₂
and we then get equation (6).
Cacetone X Chydam
Cacox X CH
KK'
K".
(6)
That this equation holds very well experimentally is made
evident by a glance at Tables XXV. to XLV. The value of
K" is about 1.25 when the concentrations of the substances
do not vary widely. But when an excess of acid is added, the
value of the constant decreases considerably as was predicted.
The reason for this is that with the addition of the acid the
percentage of increase in C is much greater than the percentage
of decrease in Cacox and consequent increase in Cacetone and
Chydam, and hence the value of K" decreases. But if we
knew the value of Cacoxcat and could substitute the data in
equation (4) there is hardly any doubt that, with a good an-
alytical method, good constants could be obtained. The
fact that equation (6) gives a fair constant, which decreases
H
61
with large increase in CH, shows that equation (2) represents
the real equilibrium conditions.
That equation (2) represents the real equilibrium condi-
tion which may be written simply in the following equation,
+
سمند
(CH,),CO + NÍ₂OH (CH₂),C = NOH + É, (7)
because the concentration of the water hardly undergoes
change, is further shown by the data in Tables XI. to XVI.
inclusive.
When acetone and hydroxylamine hydrochloride are brought
together in equivalent quantities, equation (7) should repre-
sent the reaction, and the following differential equation should
represent the course of the reaction.
dx
dt
K(A —x)² — K₁X2.
(8)
A is the original concentration of the acetone and hydroxyl-
amine in gram molecules per liter, x is the change in con-
centration of each in the time t, K is the velocity constant
for the reaction on the left in equation (7) and K, the velocity
constant for the reaction on the right. When acetoxime and
acids are brought together and react according to equation
(7) the same differential equation (8) can be used. Equation
(8) can be written in the form:
dx
dt
K, {K (A —x)³ — x
x2
K₁
{
KA2 2KAX
K₁
K₁
K
I
+ (
(¹)
1) x²
or
2A K
K₁
logn
K₁
K
2X
-1) —;
KA
K
2
-2A
K₁
VK₁
2 KA
K₁
+ 2A
K
VK,
2x (K − 1) — 2KA + 2A
K₁
K
VK,
}
2KA
K
2A
K₁
62
Reference to Tables XI. to XVI. shows that equation (9) gives
as nearly a constant value for K, as the errors of the method
will permit. A further discussion of this reaction will be given
in a subsequent paper.
The action of carbonyl compounds on the free bases and
salts of oximes, hydrazines, semicarbazides and amines is be-
ing continued in this laboratory.
EXPERIMENTAL.
Preparation of Acetoxime.
Twenty-five grams of hydroxylamine hydrochloride were
dissolved in 30 cc. water at 5° and added to a solution of 15
grams of sodium hydroxide in 20 cc. water at 5°; 25 grams of
acetone were then added. The temperature immediately
rose to 45°. The mixture was then warmed for 30 minutes
at 60°, and then cooled in ice. When the precipitate of acet-
oxime was filtered off and dried, it weighed 22 grams. When
it was recrystallized twice from water it melted at 60° to 62°.
0.1243 gram in 10 cc. water required 0.25 cc. o.1 N hydrochloric
acid to give a pink color with methyl orange.
Analytical Method.
In the two following tables there is given a general resumé
of the experiments instituted to learn the best analytical
method for the following reactions. It was apparent from
the work of Adams¹ and Haga,' that the iodometric method
is far better than the one involving the use of Fehling's solu-
tion. Since the work of Adams leaves no doubt that the use
of sodium phosphate in the iodometric method is better than
the use of sodium bicarbonate we carried out a number of ex-
periments to ascertain the best concentrations of sodium phos-
phate, iodine, etc., for our purpose. The tables show how the
amount of iodine required varies with the other conditions
when the iodine is added to the hydroxylamine solution. Since
the hydroxylamine reacts nearly quantitatively with the io-
dine according to the equation
¹ Am. Chem. J., 28, 200.
2 J. Chem. Soc., 51, 794.
63
2NH,OH + 212 →→
N₂O + H₂O + 4HI,
one-half the molecular weight of hydroxylamine hydrochlor-
ide is the number of grams used in a liter to make the normal
solutions.
¿
The method finally adopted was the addition of about 10 CC.
of the hydroxylamine solution to an excess of iodine in 10 cc.
of 10 per cent sodium phosphate solution, and titration of the
excess of iodine with o.1 N sodium thiosulphate solution. The
results are given in Table III. All the necessary check experi-
ments were made to show that small quantities of sodium
phosphate, sodium dihydrogen phosphate, acetoxime and
acetone were without much influence on the titrations. The
method is poor but is sufficiently accurate to make the pre-
liminary study of the problem.
Cc. 0.0851 N
NH2OH.HCI
solution.
0.3 gram.
IO
IO
IO
7
8.69
8.72
9.60
Table I.
Cc. 0.0858 N idoine required.
Na₂HPO4.
0.5 gram.
10.54
7.75
Calculated 10 cc. =
9.96 cc. iodine.
Table II.
Cc. 0.0853 N iodine required.
Na₂HPO4.
Excess.
10.12
II.07
10.94
Cc. 0.1008 N
NH₂OH.
HC1.
0.5 gram. 0.7 gram.
I gram.
2 grams.
I gram+8 cc.
0.1 N KOH.
IO CC.
Io per cent
solution.
ΙΟ
12.65
12.65
13.41
13.66
13.00
12.87
IO
12.02
12.67
13.39
13.83
12.96
13.13
ΙΟ 12.19
12.65
13.15
13.82
12.95
13.10
IO
12.21 12.74 13.20
}
13.06
IO
12.85 13.20
13.07
IO
13.15
13.28
12.97
IO
12.96 13.20
12.82
12.85
Calculated 10 cc. = 11.79 cc. iodine.
64
Cc. 0.1008 N
NH₂OH.HCI.
Table III.
Cc. 0.0853 N
iodine required.
IO
13.38
IO
13.19
IO
13.31
ΙΟ
13.19
Calculated 10 cc.
11.79 cc. iodine.
In all of the following work on the reactions between car-
bonyl compounds and hydroxylamine, the amount of hydroxyl-
amine, or its hydrochloride, left unchanged in 10 cc. of the
solution, corresponds to the number of cc. iodine required.
Since the tables give also the amount of iodine required for the
total hydroxylamine added, or for that formed by the com-
plete hydrolysis of the acetoxime added, it is evident that
these data enable us to calculate the concentrations of the ace-
tone, hydroxylamine and acetoxime. In practically all cases
the concentrations used are such that about 12.50 cc. o.1 N
iodine would be required to react with the total amount of
hydroxylamine, free and combined. In order to save space,
therefore, I have desisted from giving this enormous amount
of data in the tables, and have furnished only the figures
necessary to calculate the results.
Velocities of the Reactions between Hydroxylamine and Carbonyl
Compounds.
The solution of hydroxylamine used in the following tables
was made by treating 3.4725 grams NH₂OH.HCl with 50 cc.
N NaOH and diluting to 500 cc. The acetone solution was
made by diluting 1.466 grams acetone to 250 cc. with water.
A is the number of cc. iodine solution used up by 10 cc. of the
reaction mixture. Five cc. hydroxylamine solution used up
12.76 cc. iodine (A).
65
Table IV.
49.4 CC. 0.101 acetone solution and 50 cc. o.1 N NH₂OH solu-
tion at 1°. A = 12.67 cc.
t.
0.0853 N iodine.
AK.
0.5
12.67
2.I
12.67
4.5
12.67
118.0
10.05
0.0022
227.7
6.71
0.0039
304.5
5.50
0.0043
Į
Table V.
49.4 cc. 0.101 N acetone solution and 50 cc. NH₂OH solution
at 65°. A
=
i2.76.
t.
0.0853 N iodine.
AK.
I.O
12.60
(0.0127)
4.I
10.26
0.0585
8.0
8.42
0.0644
13.I
8.70
0.0354
30.I
6.14
0.035
65.0
2.87
0.053
105.5
1.72
0.060
148.2
1.15
0.068
Table VI.
50.3 cc. 0.0994 N (CH)2CO solution and 50 cc. o.1 N NH₂OH
solution at 35°. A = 11.80 cc.
t.
0.0882 N iodine.
AK.
4I
5048
II.49
0.0054
20
II.07
0.0033
9.71
0.0052
66
8.92
0.0049
86
8.24
0.0050
122
7.10
0.0054
173
6.23
0.0057
66
Table VII.
50.3 cc. 0.0994 N (C₂H)2CO solution and 50 cc. o.1 N
NH₂OH solution at 65°. A = 12.45 CC. Correction: 5 cc.
(C₂H)2CO solution used 0.56 cc. 0.0882 N iodine solution.
t.
0.0882 N iodine.
AK.
I
12.31
0.0II
5.5
II.72
O.OII
20.I
IO.IO
0.0II
39.I
8.38
0.012
63.I
8.24
0.008
91.9
7.88
0.010
142.5
4.77
0.0II
221.0
3.73
0.0105
2880.0
1.37
Table VIII.
1.142 grams CH,COH diluted to 250 cc. Of this solution
48.15 cc. is equivalent to 50 cc. NH,OH solution.
CH,COH solution used up 0.50 cc. iodine at 35°.
5 cc.
48.15 cc. 0.104 N CH,COH solution and 50 cc. 0.1 N
NH₂OH at 10.5°. A = 12.06 cc.
t.
0.0882 N iodine.
AK.
5.9
10.72
0.029
15.7
8.01
0.036
34.5
5.67
0.035
55.2
4.19
0.036
81.3
2.34
0.053
Table IX.
48.15 cc. 0.104 N CH,COH solution and 50 cc.
NH₂OH solution at 35°. A = 11.90 cc.
t.
I
3.66
6.3
II.5
35.8
0.0882 N iodine.
9.58
4.46
1.27
1.87
1.30
1
0.1 N
67
On the Hydrolysis of Acetoxime by Water and Acids, and the
Equilibrium between Acetoxime Hydrochloride and
Acetone and Hydroxylamine Hydrochloride.
In order to learn the rapidity of hydrolysis of acetoxime by
water and acids and the equilibrium point between the acet-
oxime or its hydrochloride, and the acetone and hydrox-
ylamine or its hydrochloride the following experiments were
instituted. The results show that the equilibrium point changes
with temperature. The bearing of this has been discussed in
the theoretical portion.
In making the solutions 3.6789 grams of acetoxime were
diluted to 500 cc. with water; 50 cc. of this solution were mixed
with 50.38 cc. 0.1 N hydrochloric acid solution for hydroly-
sis. Ten cc. of the mixture were withdrawn at each time
period and run into an excess of 0.0853 N iodine and 10 cc. of
10 per cent disodium hydrogen phosphate solution kept at o°.
The excess of iodine was titrated with sodium thiosulphate
solution. Column II. gives the amount of iodine used up by
the hydroxylamine, or its hydrochloride, formed.
Table X.
Hydrolysis of acetoxime with water alone. 0.3650 gram
acetoxime was diluted to 100 cc. with water and the tempera-
ture kept at 65°.
t.
O
126
I day
4 days
Cc. iodine 0.0882 N.
1.18
0.73
0.91
0.71
To 10 cc. was added 1 cc. o.1 N hydrochloric acid solution,
and the mixture was heated 30 minutes at 65°. The solution
then required 3.44 cc. of iodine solution.
68
Table XI.
50 cc. acetoxime solution and 50.38 cc. o.1 N HBr at 2°.
t.
}
I
2
3
5
9
12
18
22
35
Table XII.
0.0853 N iodine.
0.41
0.66
0.76
0.90
I.20
I.20
1.41
1.59
2.08
K
50 cc. acetoxime solution and 50.38 cc. o.1 N HBr at 3°.
K₁ = 0.197. A =
0.197. A = 13 cc. 0.0853 N iodine solution.
t.
0.0853 N iodine.
C
5
0.88
'15
1.76
34
2.23
K1.
0.0029
0.0018
0.00II
48
2.51
0.00096
61
2.88
0.00095
93
3.67
0.0011
120
3.66
338
4.00
426
3.81
Table XIII.
50 cc. acetoxime solution and 50.38 cc. o.1 N HBr at 11°.
0.269. A = 13 cc. 0.0853 N iodine solution.
K
K₁
t.
0.0853 N iodine.
K1.
2
4
7.1
ΙΟ
15
0.96
0.0050
1.22
0.0032
1.55
0.0024
2.70
0.0035
2.76
0.0025
21
3.94
0.0036
25.5
4.30
0.0046
38
4.16
0.0024
60
4.44
1
69
Table XIV.
55.5 cc. acetone (1.466 gram to 250 cc.) and 50 cc. NH₂OH.HC1
(3.4725 gram to 500 cc.) at 13.5°. A = 12.75 cc.
t.
0.88
1.67
5.5
9.0
15.33
20.5
24.67
48.12
148.5
0.0853 N iodine.
9.27
8.20
7.04
5.54
4.71
4.83
4.13
5.01
5.01
Table XV.
50 cc. acetoxime solution and 50.38 cc. o.1 N HBr at 27°.
t.
1.16
2.0
2.5
6.0
9.5
14.0
17.5
21.5
29.5
0.0853 N iodine.
I.45
2.15
2.48
4.19
4.86
5.06
5.13
5.12
5.05
Table XVI.
Suppression by KBr. 50 cc. acetoxime solution, 50.38 cc.
0.1 N HBr, and 5.9555 grams KBr (10 mols.) at 27°.
t.
0.0853 N iodine.
I
1 2 46 78
I .47
2.24
3.45
4.23
4.44
8.08
5.08
IO
15
31
5.27
5.68
5.09
70
Table XVII.
50 cc. acetoxime solution and 50.38 cc. 0.1 N HBr at 50°.
t.
噜
​0.0853 N iodine.
I
2
ΙΟ
20
45
4.44
5.69
5.97
5.97
5.95
Table XVIII.
50 cc. acetoxime solution and 50.38 cc. 0.1 N HCl at 27°.
0.0853 N iodine.
t.
Ι.Ο
1.5
2.5
4.0
5.25
7.16
10.16
15.0
1.87
2.10
3.05
3.65
4.04
4.79
5.39
5.26
5.87
31.0
When 10 cc. were withdrawn and treated to boiling for a
short time 8.72 cc. of iodine solution were required. The
remainder of the above mixture was heated to 90°. t = time
after reaching 90°.
t.
5
20
0.0853 N iodine.
7.15
7.08
This last table shows the change of equilibrium with change
in temperature.
Table XIX.
50 cc. acetoxime solution and 50.38 cc. o.1 N HCl at 50°.
t.
5
0.0853 N iodine.
5.60
IO
6.08
15
6.13
6.01
20
6.01
30
45
6.15
80
6.25
71
Table XX.
Suppression by KCl, 50 cc. acetoxime solution, 50.38 cc.
0.1 N HCl, and 3.73 grams KCl (10 mols.), at 27°.
t.
1.16
2.42
0.0853 N iodine.
TT
4.06
5.67
7.5
9.06
14.25
23.8
38.75
1.80
2.79
4.02
4.15
4.58
5.29
5.31
5.20
5.55
Table XXI.
To 47.8 cc. acetone solution (1.5166 grams in 250 cc.) was
added 50 cc. NH₂OH.HCl solution (3.4725 grams in 500 cc.)
at 65°. A = 12.50 cc. 0.0882 N iodine.
t.
5.33
7.I
37.33
102.0
0.0882 N iodine.
6.76
6.80
6.56
6.84
Table XXII.
To the 55.8 cc. left of the above mixture 4.2 cc. 1.05 N HBr
at 65°.
t.
I.O
4.I
7.8
43.6
0.0882 N iodine.
7.76
8.06
8.51
8.15
Equilibrium was thus changed by a change in concentration
of the acid present.
In the 3 following tables the concentrations are: 1.5166
grams of acetone diluted to 250 cc.; 3.4725 grams hydroxylamine
hydrochloride to 500 cc.
72
Table XXIII.
47.8 cc. acetone solution and 50 cc. NH₂OH.HCl solution at
65°. A = 12.59 cc. 0.0882 N iodine solution.
t.
0.8
1.5
2.5
6.0
1440.0
0.0882 N iodine.
6.69
6.76
6.81
6.83
6.94
Temp.
65°
Table XXIV.
47.8 cc. acetone solution and 50 cc. NH₂OHHCl solution at
varying temperatures. At 65°. A = 12.59 cc.
Time.
2.8
0.0882 N iodine.
6.50
80°
20
7.50
92°
46
7.81
80°
80
7.59
65°
102
6.63
3.5°
285
5.80
10.5°
181
4.81
Change in Equilibrium with the Change in Concentration of the
Acetone.
The following experiments were tried in order to study the
change in equilibrium produced by change in the concentra-
tion of the acetone. The amount of hydroxylamine hydro-
chloride was constant. The value of K gives the approximate
constant obtained by substituting the proper data in the form-
ula
×
+
(CH,),CO X NHOH
+
(CH3)2C=NOH X H
K.
M
as was discussed in the theoretical portion. In the small
parentheses in the headings above the tables the molecular
73
quantities of acetone are placed under the term 0.5 amount,
etc.; the amount of hydroxylamine hydrochloride used is the
unit of comparison.
Table XXV.
24 cc. 0.101 N acetone solution (0.5 amount acetone), 26 cc.
water, and 50 cc. NH₂OH.HCl solution (3.4725 grams to 500 cc.)
at 65°. A = 12.50 cc. 0.0882 N iodine.
1.
3
12.2
21.75
28
0.0882 N iodine.
8.80
8.75
8.80
8.76
Mean,
8.75
K = 1.5
Table XXVI.
I
25 cc. o.1 N NH₂OH.HC1 and 25 cc. 0.1 N acetone (1 amount
acetone) at 65°.
t.
5
7
102
0.0882 N iodine.
6.76
6.80
6.84
Mean, 6.80
K I.4
Table XXVII.
15 cc. 0.5 N acetone (3 amounts acetone), 10 cc. water, and
25 cc. 0.1 N NH₂OH.HCl at 65°. A A = 12.50 cc.
t.
0.0882 N iodine.
6.1
13
(3.15)
3.57
19.7
3.43
45.8
3.48
Mean,
3.50
K = 1.2
74
Table XXVIII.
25 cc. 0.5 N acetone (5 amounts acetone), 25 cc. o.1 N
NH₂OH.HCl at 65°. A 12.50 cc.
t.
0.0882 N iodine.
5.2
2.26
24.3
2.26
84. I
2.21
Mean,
2.24
K = I.I
Change in Equilibrium with Change in the Concentration of the
Hydrochloric Acid.
As was discussed in the theoretical portion, if there is real
equilibrium between the acetoxime hydrochloride, and the
acetone and hydroxylamine hydrochloride, this same equi-
librium point should be attained whether acetoxime be
treated with hydrochloric acid or acetone be heated with hy-
droxylamine hydrochloride. The equilibrium should, further-
more, be changed by a change in the concentration of the hy-
drochloric acid. In general, this idea is perfectly well estab-
lished by the following experimental data. The formula
+
(CH,),CO X NH, OH
×
K
+
(CH3)2C=NOH X H
seems to hold very well for those solutions containing
amounts of acetone, hydroxylamine, hydrochloric acid and
acetoxime having similar concentrations.
Acetone + NH₂OH.HC1
HCl varied.
Acetoxime + HCl ·
HC1 varied.
i
75
Table XXIX.
(0.2 HCI)
20 cc. o.1 N KOH, 5 cc. 0.5 N acetone, and 25 cc. o.1 N
NH₂OH.HCl at 65°.
t.
6
23
99
3389
0.0882 N iodine.
(2.80)
2.44
2.38
T
Mean,
2.41
Table XXX.
(0.2 HCI)
25 cc. o.1 N acetoxime (0.73 gram to 100 cc.), 5 cc. o.1 N
HCl, and 20 cc. H2O at 65º.
t.
0.0882 N iodine.
1
6.5
2.96
18.5
73.5
2.53
2.82
Mean, 2.89
Table XXXI.
(0.6 HCI)
5 cc. o.5 N acetone, 10 cc. H₂O, 10 cc. 0.1 N KOH, and 25 cc.
0.1 N NH₂OH.HCl at 65°.
t.
7
17
ㅎ​!
40
0.0882 N iodine.
4.97
5.02
5.05
Mean, 5.01
K = 1.35
76
f
Table XXXII.
(0.6 HCl)
25 cc. 0.1 N acetoxime, 15 cc. o.1 N HCl, and 10 cc. H₂O
at 65°.
t.
IO
0.0882 N iodine.
5.07
33
145
4.85
5.00
. Mean, 4.97
Table XXXIII.
(1 HCl)
25 cc. o.1 N acetone and 25 cc. o.1 N NH₂OH.HCl at 65°.
t.
5
7
102
0.0882 N iodine.
6.76
6.80
6.84
Mean,
6.80
K = 1.4
Table XXXIV.
(1 HCl)
25 cc. o.1 N acetoxime and 25 cc. o.1 N HCl at 50°.
t.
15
45
80
0.0882 N iodine.
6.13
6.15
6.25
Mean, 6.17
77
t
Table XXXV.
(1.4 HCl)
10 cc. H₂O, 5 cc. 0.5 N acetone, 10 cc. o.1 N HCl, and 25 cc
0.1 N NH₂OH.HCl at 65°.
t.
8.5
21
0.0882 N iodine.
7.29
7.30
66
7.37
109
7.43
Mean, 7.35
K = 1.06
Table XXXVI.
(0.8 HCl)
20 cc. o.1 N HCl, 5 cc. H₂O, and 25 cc. o.1 N acetoxime
at 65°.
t.
0.0882 N iodine.
6
5.63
27.33
49
5.74
5.67
Mean, 5.68
K = I.I
Table XXXVII.
(1.8 HCl)
5 cc. 0.5 N acetone, 20 cc. o.1 N HCl, and 25 cc.'o.1 N NH₂OH.
HCl at 65°.
0.0882 N iodine.
t.
8.00
7
27
7.96
54
7.94
Mean,
7.96
K = 0.94
78
Table XXXVIII.
(1.8 HCl)
4.5 cc. N HCl, 20.5 cc. H₂O, and 25 cc. o.1 N acetoxime
at 65°.
t.
0.0882 N iodine.
7
7.64
23.5
141
7.76
7.80
Mean, 7.75
Table XXXIX.
(3 HC1)
5 cc. 0.5 N acetone, 5 cc. N HCl, 15 cc. H₂O, and 25 cc
0.1 N NH₂OH.HCl at 65°.
t.
0.0882 N iodine.
8.30
II
8.35
29
8.44
4I
8.37
142
Mean,
8.34
K = 0.58
Table XL.
(2.5 HCI)
6.25 cc. 1.0 N HCl, 18.75 cc. H₂O, and 25 cc. o.1 N acet-
oxime at 65°.
t.
12
21
47
70
0.0882 N iodine.
(8.02)
8.39
8.34
8.44
Mean,
K = 0.68
8.39
1
79
Table. XLI.
(17 HCl)
5.21 cc. 7.68 N HCl, 5 cc. 0.5 N acetone, 14.79 cc. H₂O, and
25 cc. o.1 N NH₂OH.HCl at 65°.
t.
15
45
0.0882 N iodine.
9.94
10.26
Mean, IO.IO
Table XLII.
(5 HCI)
12.5 cc. N HCl, 12.5 cc. H2O, and 25 cc. o.1 N acetoxime
at 65°.
t.
5.33
354
20
54
0.0882 N. iodine.
8.54
8.52
8.44
Mean, 8.50
}
The three following tables give a resumé of the chief results ob-
tained at 65°. In the first table the upper column gives the
number of cc. used for the titration. The solution was o.1 N
with respect to the hydroxylamine hydrochloride, and the
concentration of the acetone was 0.5, 1, 3 or 5 times 0.1 N,
as indicated in the second column. The third column gives
the number of cc. iodine required to oxidize the hydroxylamine,
or its salt.
Table XLIII.
Cc. solution
Molecules acetone
Cc. iodine required
IO
IO
ΙΟ
IO
0.5
8.77
I
3
5
7.44
3.49
2.24
The second table shows the change in equilibrium with
a change in concentration of the hydrochloric acid.
80
Table XLIV.
Cc. solution:
o.IN NH,OH.HC.
+o.1 Nacetone
Molecules HC1
Cc. iodine required
IO
IO
IO
IO
0.2 0.6 I.O I.4
ΙΟ
IO
IO
1.8 3
17
2.41 5.01 6.80 7.35 7.96 8.34 10.10
The third table gives the equilibrium attained when o.1 N
acetoxime is treated with varying amounts of hydrochloric
acid. For a given amount of hydrochloric acid the equilibrium
point is practically the same as it is in Table XLIV.
Cc. solution:
Table XLV.
0.1 N acetoxime
+ HCl
Molecules HC1
ΙΟ
ΙΟ
0.2
0.6
IO
0.8
ΙΟ
IO
ΙΟ
ΙΟ
1.0 1.8 2.5 5
Cc. iodine required 2.89 4.97 5.68 6.17 7.75 8.39 8.50
ON THE REACTION OF ACETONE WITH PHENYLHYDRAZINE AND
PHENYLHYDRAZINE HYDROCHLORIDE.
A preliminary announcement is made of the study of the
action of acetone on phenylhydrazine, and on its hydrochloride.
After the results of the action of acetone on hydroxylamine
had been obtained it was seen that the reaction of carbonyl
compounds with hydrazines, and with their salts, might be
reversible. The idea seems to be confirmed by the experimen-
tal data.
(CH2)2CO + H₂N-NHC.H
5
(CH,),C:NNHCH + H,O;
(CH3)2CO + H‚N—NHCH¸ +Cl =
5
+
5
(CH¸)₂C : ÑNHCH¸H + H₂O + Cl.
The method of following the reaction was that of Meyer.¹
It does not seem to work well in the case under consideration,
but further study may lead to improvement. The two following
1
¹ J. prakt. Chem. [2], 36, 115.
81
1
tables show that while the reaction between phenylhydrazine
and acetone seems to go nearly to completion, the phenyl-
hydrazine hydrochloride reacts at most only very slowly with
the acetone, and the reaction seems to be reversible. The changes
are very slow in comparison with those between acetone and
hydroxylamine or its hydrochloride. The work will be con-
tinued and the results reported must be considered only tenta-
tively.
Table I.
50 cc. phenylhydrazine solution (2.7028 grams in 250.26
cc.), 40 cc. water, and 10 cc. 0.5 N acetone at 27°.
t.
O
5
Cc. iodine
required for
10 CC. solution.
Cc. iodine solution
required for 5 cc.
phenylhydrazine
solution at 22°.
17.88
17.88
13.62
24
II.82
40
10.30
184
9.46
1374
5.47
4252
2.72
5856
2.04
8907
1.62
Table II.
15.09
50 cc. phenylhydrazine hydrochloride solution (3.6113
grams in 250 cc), 40 cc. water, and 10 cc. 0.5 N acetone at 27°.
t.
O
2
2722
4309
7381
Cc. iodine
required for
IO CC. solution.
17.23
17.23
13.63
13.13
13.17
Cc. iodine solution
required for 5 cc.
phenylhydrazine
hydrochloride
solution at 22°.
17.23
15.97
16.93
ON THE FORMATION AND SAPONIFICATION OF ESTERS AND THE
THEORY OF REVERSIBLE CATALYTIC REACTIONS.
The theory of the reversible reaction between organic acids
'Strache: Monats. Chem., 12, 524.
82
7
3
4
8
and alcohols on the one hand and the esters and water on the
other, has been discussed in some detail by Zengelis,¹
Euler,2 Lapworth, Mellor, Kastle," Goldschmidt," Acree and
Johnson, and especially by Stieglitz. While the theories
held by individuals vary somewhat in detail they all have
as a basis the general idea that intermediate products are directly
concerned in the reactions. The writer wishes to discuss the
matter further in the light of some work done on the urazoles.
The experimental data of Berthelot and Gilles, Menschut-
kin,10 Goldschmidt, Ostwald,11 Guldberg and Waage, 12 Wijs, 13
Knoblauch¹ and Kistiakonsky, 15 amply prove that the sapon-
ification of esters in dilute water solution takes place according
to the equation,
dx
dt
Ktran. X Cester X CH₂O X CH.
9
What is the mechanism of the reaction? It is well known
that esters are weak bases and form salts with acids. Baeyer¹6
and Villiger isolated salts formed by the union of the esters
of acetic, benzoic and oxalic acids with hydroferrocyanic acid
and hydroferricyanic acid. Rosenheim¹7 and his students
proved that esters show their basic properties by forming
double salts with antimony pentachloride and stannic chloride.
Walker, Archibald, Steele and McIntosh 18 showed that esters
unite with liquid hydrochloric acid and form salts which are
1 Ber. d. chem. Ges., 34, 1901.
2 Z. physik. Chem., 36, 405, 663; 40, 501; 47, 356.
8 See Mellor's "Chemical Statics and Dynamics," 1904, p. 289.
4 Ibid.
5 Am. Chem. J., 19, 894. P. Am. Assoc. Adv. Sci., 47, 238.
6 Ber. d. chem. Ges., 28, 3218; 29, 2208; 39, 711.
7 Am. Chem. J., 37, 410.
8 Congress of Arts and Science, St. Louis, 1904, 4, 276.
9 Ann. Chim. Phys. [3], 65, 385; [3], 66, 5; [3], 68, 225; Compt. rend., 53, 474, etc.
10 Ann. Chim. Phys. [5], 20, 289; [5], 23, 14; [5] 30, 81, etc.
11 J. prakt. Chem., [2], 28, 449.
12 Ibid. [2], 19, 82.
13 Z. physik. Chem., 11, 492; 12, 514.
14 Ibid., 22, 268.
15 Ibid., 27, 250.
16 Ber. d. chem. Ges., 34, 2692, 4189.
17 Ibid., 34, 3377; 35, 1115; 36, 1833; 37, 3662; 38, 2777.
18 Z. physik. Chem., 55, 129. Phil. Trans., 205, 99. J. Chem. Soc., 85, 919, 1098;
87, 784, 1013. Ber. d. chem. Ges., 34, 4115. J. Am. Chem. Soc., 27, 26; 28, 588.
83
dissociated in the liquid hydrochloric acid. They expressed
the opinion that the ester unites with a hydrogen ion and
forms a complex cathion. A large amount of work on other
carbonyl compounds, already referred to in this paper, leaves
no doubt that esters form small quantities of salts in acid solu-
tions, and the work of Coehn¹ on dimethylpyrone hydrochloride
makes it probable that the ester forms part of the cathion.
Finally, the writer has been able to show that the addition
of small quantities of methyl acetate, ethyl acetate, methyl
benzoate, 1-phenyl-3-ethoxyurazole, 1-phenyl-3,5-diethoxy-
urazole, or benzaldehyde to alcoholic or aqueous hydrochloric
acid causes a lowering of the conductivity sufficient to indicate
the formation of small amounts of ester salts in solution. The
following table gives the data obtained:
Substance.
Amount of sub-
stance added to
25 cc. solution.
Solution used.
Ethyl acetate
O. I CC.
Methyl benzoate
O. I CC.
0.1 N alcoholic hydro-
chloric acid
0.1 N alcoholic hydro-
1.6
chloric acid
0.8
Benzaldehyde
O. I CC.
0.1 N alcoholic hydro-
chloric acid
5.7
Benzaldehyde
0.2 CC.
0.1 N alcoholic hydro-
chloric acid
IO.O
zole
Phenyl-3-ethoxyura-
zole
Phenyl-3-ethoxyura-
0.05 gm. 0.1 N hydrobromic acid I.I
0.1 gm. o.1 N alcoholic hydro-
chloric acid
2.7
Phenyl-3-ethoxyura-
zole
0.5 gm. 0.1
Phenyl-3,5-diethoxy-
N alcoholic hydro-
chloric acid
10.6
urazole
0.1 gm. o.1
Phenyl-3,5-diethoxy-
N alcoholic hydro-
chloric acid
3.3
urazole
0.5 gm. o.1 N alcoholic hydro-
chloric acid
7.9
Methyl acetate
O. I CC.
0.1 N hydrobromic acid
I.O
Ethyl acetate
O. I CC.
0.1 N hydrobromic acid
I.O
1 Ber. d. chem. Ges., 35, 2673.
Decrease in con-
ductivity.
Per cent.
84
Furthermore, the decomposition of sulphonic esters¹ and ura-
zole esters² by hydrochloric acid in which ethyl chloride is elim-
inated, indicates that the esters form hydrochlorides.
The constitution of these ester salts is a question of.
interest. Many of the workers in these fields are of the opinion
that the salts are derivatives of tetravalent oxygen and have
the formula I and II.
C1
HOC1
RC(O)O-R
H
OH
RC-O-R RC(C1)OR
OH
RC=O(CI)R
I.
II.
III.
IV.
CH,N-
--N
CH,N-
-NH
C1
od
CO-R
OC
C(CI)OR
H
NCH,
NCH,
V.
VI.
H
CH,N- -NC1
CH,N-
--NH
oć
||
COR
oć
R
C1
NCH
VII.
NCH,
VIII.
Since many esters and hydrochloric acid yield ethyl chloride
formulas III. and IV. should also be considered and all four may
be in tautomeric equilibrium. The urazole ester hydro-
chlorides may also exist in the form, V., VI., VII. and VIII.
in equilibrium, with some one or two forms in preponderance.
Since the esters then form salts it might be at once suspected
that in the saponification of esters by water in the presence of
acids the ester cathion is saponified, just as the alkyl halides
¹ Am. Chem. J., 19, 894.
2 Acree and collaborators: Am. Chem. J., 27, 118; 31, 185; 32, 606; 37, 71, 361;
88, 1. Ber. d. chem Ges., 35, 553; 36, 3139; 37, 184, 618.
85
react with anions, and acetamide cathions and imido ester
cathions are hydrolyzed. Euler, Bredig,' Lapworth, Stieg-
litz, and Acree and Johnson have held that view, and many
of the following equations have been developed by these writers,
especially by Stieglitz. The equations are given here again,
with others, to develop the entire subject.
If Cest gram molecules of ester and enough hydrochloric
acid to give СH gram ions of hydrogen ions are brought to-
gether in 1 liter of water we shall have the following reaction
established very quickly, and get the equation
+
+
CH,COOR + H
→→CH,COOR.H
Kw
Κω
(Cesty) (CH-Y)
Csalt dis,
(2)
y
Кь
Kb
in which y is the very small amount of salt formed; the hydro-
gen ions from the water and small non-dissociated portions
of the ester salt are disregarded. If now the ester cathion is
the substance hydrolyzed, we shall have, if we disregard the
very small reverse reaction,
+
CH,COOR.H + H₂O
+
CH,COOH + ROH + H
-dC salt dis
dt
Ktrans Csalt dis X CH₂O.
(3)
When the formation of the salt from the ester and hydrogen
ions takes place very rapidly in comparison with the saponi-
fication of the ester cathion, and the value of y is negligible
in comparison with Cest and CH we can substitute for Csalt dis
Къ
in equation (3) the value Cest X CH and we then get, as
Kw
has been developed before in the other sections,
-dC salt dis
dt
dx
dt
Ktrans Kb
Kw
·(Cest-x)CHX (CH₂0-x), (4)
which is only another form of equation (1). This equation
¹ Z. Elek. Chem., 9, 118; 10, 586; 11, 528.
86
seems to hold whether the hydrogen ions come from water,
weak acids or stronger acids. We have then harmony between
the quantitative data and the idea that the ester cathion may
be the substance hydrolyzed. The ester exists in solution prob-
ably only as free base, cathions and undissociated salt. The
free base is hydrolyzed certainly only very slowly by the water
as direct experiment shows. If the undissociated ester
hydrochloride were the substance chiefly hydrolyzed we should
have, as has been developed in the previous sections, the fol-
lowing equation expressing the reaction velocity:
dx
dt
Ktrans Kb
Kaffin Kw
·(Cest — x) × (CH₂0—x) × CH. (5)
Since the velocity of hydrolysis of esters is not proportional
to the square of the concentration of the hydrogen ions, it is
evident that the non-dissociated ester salt can not be greatly
concerned in the saponification. Furthermore, since the free
ester is not appreciably concerned in the reaction there is left
only the ester cathions, and this seems to be the substance
which is really hydrolyzed. But the moment the hydrolysis
of the ester begins the reverse reaction, the formation of the
ester from the organic acid and the alcohol also begins.
The reactions involved in formation of esters from organic
acids and alcohols in the presence of hydrogen ions are probably
exactly analogous to those involved in the saponification
of the esters. Lapworth, Euler, Kastle, and Stieglitz have
pointed out that the organic acids probably unite with the
hydrogen ions to a small extent and that this complex organic
acid cathion reacts with the alcohol and forms the ester, water
and hydrogen ions. There is no doubt that the organic acids
do have weakly basic properties, just as many ureas, pyrimi-
dines, urazoles and amides have both basic and acid properties.
Rosenheim¹ found that organic acids behave like the esters
in their action on antimony pentachloride. Hell and Mühl-
hauser2 found that acetic and other organic acids form unstable
¹ Loc. cit.
Ber. d. chem. Ges., 12, 734
87
hydrobromides, such as 2CH,COOH.HBr. McIntosh¹ observed
similar phenomena and Farmer² showed, too, that organic acids
have basic properties.
If, then, the organic acid does actually unite with the
hydrogen ions and form a cathion, which reacts with the alco-
hol, we shall have the following equation holding under
+
HCH,COOH.H
сн.соон.н
Kw Cacid salt dis,
CH3COOH + H
(Cacid-y')(CH-y')
Kw
K'; y
K'o
(6)
exactly the same conditions which apply to the ester. K' is
the affinity constant of the acetic acid as above, and y' is the
small amount of cathion formed, the molecular form of the
salt being so small in amount as to be disregarded.
If the acid cathion is the substance which reacts with the al-
cohol we shall have, if we again disregard the small amount
of the reverse reaction,
+
CH,COOH.H + ROH
+
CH,COOR + H₂O + H
-dCacid salt dis
dt
K'transCacid salt dis X Calc.
(7)
But just as with the esters we can substitute for Cacid salt dis
K'b
in (7) the value
Cacid X CH. We then get, as developed
Kw
with the esters,
dx
dt
equation (8) as representing
K'b
K'trans Kw
(Cacid-x) x (Calc-x) X CH, (8)
+
the reaction which should be found to hold experimentally
if the organic acid first unites very rapidly with the hydrogen
ions and forms a complex cathion, CH,COOH.H, which reacts
slowly with the alcohol and forms ester, water and hydrogen
ions. Equation (8) is actually found to represent the velocity
¹ J. Am. Chem. Soc., 28, 588.
2 J. Chem. Soc., 83, 1440.
88
of formation of the esters. We are led, then, to the idea that
the reversible reactions in the system, water, alcohol, ester,
organic acid and hydrochloric acid are brought about by the
formation and reactions of intermediate cathions produced by
the union of hydrogen ions with the ester and organic acid.
+
Whether the acid cathion, CH,COOH.H, has the formula IX.,
X. or XI. need not be discussed.
CH,C(O).H
H
+
+
CH,C(OH)₂
IX.
X.
H
CH,C-OH
XI.
When the system is in equilibrium just as much ester is formed as
is saponified into organic acid. The two terms dx in equations
(4) and (8) are, therefore, equal and we get, by substitution,
equation (9) as representing the equilibrium conditions.
Kw
Kb
Ktrans Kw
Cest X CH₂OX CH
K'trans
K'b Cacid X Calc XCH
or
(9)
Cest X KCH₂0
K'Cacid X Calc.
Cest CH₂O Cacid and Calc are the concentrations of thes-
substances at the equilibrium point. CH is the original cone
centration of the hydrogen ions less the very small amount
united with the ester and organic acid. The equilibrium
point is apparently independent of the concentration of the
hydrogen ions.
To recapitulate then: The idea that the reversible reactions
taking place in the system ester, water, acid, alcohol and hydro-
chloric acid are due to reactions of the complex cathions, formed
by the union of a very small amount of the hydrogen ions with a
small amount of the ester and organic acid, leads to equations
which hold experimentally. The assumption explains, in
equations (4) and (8), why the velocity of saponification and
of esterification increases directly in proportion to the con-
centration of the hydrogen ions. It further makes clear, in
89
equation (9), the experimentally established fact that the equi-
librium of the system is not appreciably changed by change
in the concentration of the hydrogen ions. These ideas have
already been developed by Euler, Lapworth, Kastle and es-
pecially by Stieglitz, and they have received very good experi-
mental verification. Goldschmidt¹ has recently pointed out
some discrepancies not entirely in harmony with the above
equations and doubtless many others will be reported later.
The assumption, however, gives a good working basis and may
be used as a guide for the further work needed to clear up the
whole matter. There is one very serious objection to an assump-
tion common to the ideas advanced by Euler, Zengelis and
Lapworth. Lapworth proposed the idea that the organic
acid unites with the hydrogen ion,
OH
+
+
CH,COOH + H
CH,C-
(1)
OH
and that this product then reacts with the alcoholate ion as
follows:
OH
+
CH,C-
OH
OH
+C,H,CH,C-OC₂H,
3
5
OH
CH,COOCH, H₂O (2)
The objection is the following: The increase in the concen-
tration of the hydrogen ions in the solution of the organic
acid and alcohol to n times its former value would, it is true,
cause the concentration of the organic acid cathion in equa-
tion (1) to become approximately n times as great; if the
concentration of the alcoholate ions in (2) were to remain the
same then the reaction velocity would become n times its former
value. But if the alcoholate ions come from the dissociation
of the alcohol according to equation (3)
1 Goldschmidt and Sunde: Ber. d. chem. Ges., 39, 711.
90
C₂H₂OH CHŌ + É
+
(3)
the increase of the H concentration to n times its former value
would cause the concentration of the C₂HO ions to become
the nth part of its former value. The product of the alcoholate,
ions C₂H₂O, and the organic acid cathions CH,C(OH), in
(2) would, therefore, not be changed at all and the reaction
velocity, if Lapworth's explanation were correct, would remain
unchanged with change in the concentration of the hydrogen
ions. The same thing would hold true of the reverse reaction
expressed as follows,
OC₂H 5
+
(4)
OH
CH,COOCH, + H CH,C
5
followed by the reactions in equation (5).
OC₂H¿
5
+
CH,C-
OH
OH
+ OH CH,C-OC,H,
OH
5
CH,COOH + C₂H₂OH (5)
Although an increase in the concentration of the hydrogen
ions to n times a former value would cause the concentration
of the ester cathion in (4) to become n times as great, yet this
same increase in the concentration of the hydrogen ions would
cause the concentration of the hydroxyl ions in (5) to become
the nth part of its former value, and hence the velocity of the
reaction would be independent of the concentration of the
hydrogen ions. The same objection holds for certain assump-
tions made by Euler and Zengelis and these will be discussed
later. Especially, however, must it be emphasized that the
assumption of the ionization of acetic acid into acetyl and hy-
droxyl ions and CH,CO, OH, and of alcohol into ethyl and hy-
droxyl ions, C,H, and OH, fails to meet the requirements of
the mass law in the reactions under consideration. It is clear
+
+
91
then that the alcohol and water react with the acid cathion
and the ester cathion not as ions but as neutral molecules,
just as the neutral ethyl iodide reacts with urazole ions, hydroxyl
ions, etc. The water or alcohol is probably added to the carbonyl
group in these reactions, but this is not certain.
OH
CH,C +
ỐC,H,
+ H₂O
CH,C-OH
5
H
ỐC,H,
CH,C
+
OH
H
H
+
CH,COOH + H+ C₂H₂OH (6)
OH
+ ROH
CH,C-OR
+
OH
O
H
+
CH,C-R+ H₂O+H (7)
In the saponification of esters and amides by alkalies the al-
kali probably attacks the carbonyl group. Euler¹ and others
referred to above have shown that carbonyl compounds, such
as aldehydes, have both basic and acid properties.
+
CH,COOR+K+ OH + H₂O →→→
състо
NH₂
CH,C-OH
+
+
+ K + H₂O =
OC₂H
5
K
CH,COO + ROH + + H‚0 (8)
+ K + OH + H₂O
1 Ber. d. chem. Ges., 38, 2551; 39, 344.
92
C
CH,C-OH + K + H₂O
+ H₂O →→
NH₂
CH,COO+K+NH+H,O (9)
3
In the consideration of the hydrolysis and the formation of
ordinary esters one phase of the work does not apply, but it
must be developed for other esters.
Although the hydrochlorides of the ordinary esters do not
decompose appreciably into the alkyl chlorides and the organic
acids, some ester hydrochlorides do suffer this transformation
along with the hydrolysis. A notable case is that of the sul-
phonic esters. When a sulphonic ester is treated with water
and hydrochloric acid, two apparently independent side reac-
tions take place. One is the hydrolysis of the ester into the
sulphonic acid and the alcohol corresponding, and the other is
the decomposition of the sulphonic ester hydrochloride into
the alkyl chloride and the sulphonic acid.¹
+
I. CH₂SOC₂H, + H + Cl + H₂O
+
CH¿SOC¿Ã¿Í + H₂O + Cl
+
CH¿SO₂H + C₂H¸OH + É + C1.
II. С‚Í‚SО¸Ñ‚н¸ + H+ C1 C,H,SO,C,H,.HC1
CH¿SOC₂H¸
→→
CH¿SO₂H + С₂H¿C1.
Evidently the amount of transformation through each of
the reactions I. and II. depends upon the relative stability of
the sulphonic ester cathion towards water and the stability
of the sulphonic ester hydrochloride. These 2 factors will
doubtless vary with the ester, temperature and other condi-
tions. Apparently, it should be possible to suppress the re-
action I. and give reaction II. more opportunity to become the
chief one by treating the sulphonic ester in alcoholic hydro-
chloric acid. This has been done with certain urazole deriva-
tives.
1 Kastle and Frazer: Am. Chem. J., 19, 894.
93
We should then expect to find some esters, the cathions of
which are so stable towards water that the esters would hardly
undergo hydrolysis at all, but the hydrochlorides of which
might easily decompose into the acids and an alkyl chloride.
Such esters are those of the urazoles. A brief account of their
properties will be given here, and a more detailed statement
will be made later.
The 1-phenyl-3-ethoxyurazole is not saponified by aqueous
hydrobromic acid, but is decomposed quantitatively by alcoholic
hydrochloric acid into phenylurazole and ethyl chloride. Five
cc. 0.0992 N hydrobromic acid and 0.1 gram phenyl-3-ethoxy-
urazole were heated 12 hours, at 100°. The solution then ti-
trated against 5.00 cc. 0.0995 N potassium hydroxide in the
presence of methyl orange and 10.00 cc. 0.0995 N potassium
hydroxide in the presence of phenolphthalein. This shows
that no hydrobromic acid was used in the formation of ethyl
bromide and phenylurazole. The solution was acidified with
sulphuric acid and extracted with chloroform. No phenyl-
urazole was obtained, but when the chloroform filtrate was evap-
orated, o.1 gram of 1-phenyl-3-ethoxyurazole, m. p. 148°,
was recovered. In order to study the reaction quantitatively
we used the 1-phenyl-3,5-diethoxyurazole and alcoholic hydro-
chloric acid in equimolecular quantities in 0.5 N solutions.
CH,N-- -N
с̧нос
C
N
doc
COC₂H₁.
5
Since the 2,3-amide group is a much stronger acid than the
4,5-amide group it was predicted that the 5-ethoxy group would
be a very much stronger base than the 3-ethoxy group and
would unite with, and react with, the hydrochloric acid nearly
to the exclusion of the 3-ethoxy group. This prediction was
happily verified quantitatively by experiment. The reactions
were carried out in small sealed tubes at 60°, and after the reaction
was stopped the contents were poured into water in extraction
funnels. The unchanged hydrochloric acid was titrated with
standard alkali in the presence of methyl orange and the 1-
94
phenyl-3-ethoxyurazole formed was then titrated with stand-
ard alkali in the presence of phenolphthalein. The unchanged
1-phenyl-3,5-diethoxyurazole was extracted by means
chloroform and weighed.
of
If the urazole ester hydrochloride is decomposed directly
we should have the reaction expressed by the following equa-
tions:
C1
ROC₂H + H+ C1 R-O-C₂H, →→
Cl R—O—C₂H, ⇒ ROH + C₂H¿C1.
H
-dC est hcl
dt
Ktrans Cest hcl,
(1)
hcl
in which Cest het is the concentration of the urazole ester hydro-
chloride at any moment. But the concentration of the ester hy-
drochloride can be expressed approximately, as has been de-
veloped several times above, in terms of the concentrations of
the ester, hydrogen ions and chloride ions at any moment
and can be represented by the equation
C1
ROC₂H, + H+ C1 R-OC,H¸.
(Cest—x)(Cc-x)CH
H
Kaffin Kw
Kb
Cest hel
(2)
in which (Cest-x), (Cɑ—x) and CH are the concentrations of
the ester, chloride ions and hydrogen ions at any moment. We
can, therefore, substitute for Cest het in (1) its value in (2) and
we then get equation (3)
hcl
-dCest hel
dt
dx
dt
Ktrans Kb
(Cest-x)(Cc-x)CH =
Kaffin Kw
K(Cest-x)(Ca—x)CH (3)
This equation will not hold exactly since the value of C. does
not remain contant as indicated in (3) but decreases to some
extent because the urazole acid formed is weaker than hydro-
i
95
:
chloric acid. We should expect the value of K to decrease,
and if the urazole acid formed were very weak, equation (3)
would become practically trimolecular.
The following data, however, show, qualitatively, that the
urazole ester actually does act upon the hydrochloric acid and
form ethyl chloride. The experiments are given in a tabu-
lar form for convenience.
Time in minutes.
8
x.
A-x.
AK
=
t(A-x)
15
0.528
0.472
0.075
32
0.706
0.294
0.075
60
0.741
0.259
0.048
180
0.913
0.087
0,058
Average, 0.064
As a consequence of this decomposition of the ester hydro-
chloride it has been impossible, as was predicted, to obtain
the esters by heating the urazole acids with alcoholic hydro-
chloric acid.
This work on the urazole esters and sulphonic esters will
be continued.
The discussion of the reversible reaction between esters,
water, alcohol and organic acid has led to an understanding
as to why the three so-called laws¹ of catalysis apply to this
particular case. These laws may be expressed as follows:
(1) When the catalyzer is not changed during the reaction it
affects only the velocity of the reaction, but does not change the
nature of the reaction or the apparent order of the reaction.
(2) The catalyzer affects the velocity constant directly in pro-
portion to the concentration of the catalyzer.
(3) A change in the concentration of the catalyzer does not
change the equilibrium point in reversible reactions.
These three so-called laws have been found to hold so well for
the esterification work that they have been assumed to hold
for all catalytic reactions. The esterification work, the hy-
drolysis of amides, and the inversion of cane-sugar are prac-
1 For an excellent discussion of catalysis see Herz "Die Lehre von der Reaktions-
eschleunigung durch Fremdstoffe," Ahren's Sammlung, Vol. XI, p. 103.
96
tically the only well-known cases in which a catalytic reac-
tion has been well studied, and it is rather surprising that
these three cases should be the basis of the above so-called laws.
It will now be shown that these so-called laws are not laws at
all, but apply only to certain special cases, and further that
these so-called laws have no physical or chemical basis but
are really only a brief statement of the results actually obtained
experimentally. They cannot be used to make predictions
concerning all catalytic reactions, but are only approximate
expressions of special reactions.
There are two classes of reactions that must be considered
in showing that these laws for catalysis by acids (or bases)
do not hold: (1) (A) Simple reactions in which one reaction
constituent is a strong base (or acid), and (B) reversible re-
actions in which a constituent of one reacting set of the sub-
stances is a much stronger base (or acid) than the correspond-
ing base (or acid) in the opposing set of substances. (2) (A)
Simple reactions in which the catalyzer affects the reaction
velocity in proportion to the square, or other power of its con-
centration, and (B) reversible reactions in which the velocity
of one reaction increases as the m power of the concentration
of the catalyzer increases, while the velocity of the reverse
reaction increases in proportion to the m power of the concen-
tration of the catalyzer. These cases will be considered in the
order given.
(1) If in a reaction one of the constituents is a compara-
tively strong base, such as ammonia, aniline, etc., and it enters
into the reaction through the reaction of its cathion with the
other constituents, then the velocity of the total reaction can-
not increase directly in proportion to the increase in the con-
centration of the hydrogen ions added. The consideration
of the hydrolysis of cane-sugar will make this clear. In the
hydrolysis of cane-sugar according to the following equation,
the amount of hydrogen
+
(C¸H₁105)2O + H₂O + H + C1 →
+
(C‚н„О¸)₂OH + H₂O + Cl
11
(Csug—y)(CH—y)
2C,H12O6 + H +
H+ē.
KC sug cat,
(1)
97
H
ions and of cane-sugar used to form the cane-sugar cathion is
so small that the concentrations of these two are hardly affected,
and (С-y) and CH are practically equal. It follows, then,
that if the concentration of the hydrogen ions added were
made twice as great the (2СH-y') corresponding to the
new conditions would be practically twice as great as before,
and the new value of Csug cat would also be twice as great
as before. The velocity of the reaction would then be twice
as great, as we actually find by experience.
Suppose, however, that, even though the sugar did not re-
act appreciably with water and form a cathion of the corre-
sponding base (ammonia and aniline are such cases), it could
unite almost completely with a molecular quantity of hydro-
chloric acid, just as ammonia and aniline do. Then the addi-
tion of a quantity of hydrochloric acid equivalent to one-fourth
of the cane-sugar would cause one-fourth of the cane-sugar to
be changed into the corresponding cathions and the reaction
velocity would have a certain value. The addition of twice
the amount of hydrochloric acid would cause nearly half of
the cane-sugar to be changed into cathion and the velocity
constant would become nearly twice as great as before. The
addition of one molecular quantity of hydrochloric acid would
cause the concentration of the sugar cathion and the velocity
constant to become nearly four times the former value.
Up to this point, then, the velocity constant would increase
nearly directly in proportion to the increase in the amount
of hydrochloric acid added. But the further addition of hy-
drochloric acid would not cause the corresponding increase
in the velocity constant, because the cane-sugar would be al-
ready nearly completely converted into cathions and the fur-
ther addition of hydrochloric acid would cause only a slight
increase in the concentration of the cathions. In fact, the ad-
dition of much hydrochloric acid would cause a suppression of
the ionization of the cane-sugar hydrochloride and hence a
decrease in the concentration of the cathions and the velocity
constant of the reaction. It is evident, then, that if one of
the reacting constituents is a fairly strong base which enters
into the reaction through its cathions the velocity of the re-
98
action cannot increase directly in proportion to the concentra-
tion of the acid added. Examples of this are the reactions
between carbonyl compounds and hydroxylamine, the hy-
drolysis of amides by aqueous solutions of acids, and the hy-
drolysis of imido esters by acids. Under these conditions
the second law of catalysis cannot hold. It can hold only
in those cases in which the base is so weak that only a trace
of the salt is formed; since these are the only cases studied
up to this time it is not surprising that not much further thought
was given to the matter.
(2) The third law of catalysis cannot hold in those reversible
reactions in which one constituent of one reaction is a strong
base, while the corresponding constituent of the reverse re-
action is a very weak base, provided the bases enter into the
reactions through their cathions or salts. This has already
been discussed in the reversible reactions between carbonyl
compounds and hydroxylamine and its hydrochloride. These
reactions are accelerated by the addition of hydrochloric acid.
+
wwwvers
(CH,),CO+NH,OH+H
+
(CH,),CO+NH,CH
+
(CH,),C = ÑHOH + H₂O →→ (CH₂),C = NOH + H.
The acetoxime is a very weak base and hence unites with
only a small part of the acid when one molecular quantity of
hydrochloric acid is added. The addition of two molecular
quantities of hydrochloric acid would cause the formation of
nearly twice as much acetoxime cathion and hence the velocity
of the hydrolysis of the acetoxime cathion should be nearly
twice as great. But the addition of one molecular quantity
of acid to the hydroxylamine changes the hydroxylamine
practically completely into the hydroxylammonium ions, and
the addition of two molecular quantities of acid would hardly
change the concentration of the hydroxylammonium ions.
It is evident, then, that the equilibrium in the system given
above would be changed by the addition of more acid. Know-
ing that the acetoxime is the weak base, we could predict
that the addition of more acid would cause the formation of
more acetoxime cathion from the acetoxime then in solution
99
but would cause no further appreciable formation of hydroxyl-
ammonium ions from the hydroxylamine then in solution.
As a result, because of the equilibrium between the water and
acetoxime cathions on the one hand and the acetone and hy-
droxylammonium ions on the other the addition of more
acid causes a change in the equilibrium of the system and
results in the formation of more of the hydroxylammonium
ions, or ions corresponding to the stronger base.
(3) The second law of catalysis cannot hold in those reac-
tions in which changes are brought about by the union of very
small amounts of two, three, or more ions, or molecules, of the cat-
alyzing agent with a very small amount of some compound in
the reaction system, which addition product then reacts with
other constituents. This case has already been considered
in the rearrangement of the acetylhalogenaminobenzene de-
rivatives, into halogenacetanilide derivatives, where it
was shown that the velocity of this catalyzed reaction in-
creases as the square of the concentration of the hydrogen
ions instead of as the first power demanded by the second
law of catalysis. We can readily see that in some reactions
involving some reaction similar to a hydrolysis we might
have two, three or more ions, or molecules of the catalyzeruniting
with some constituent and the further transformation of this
addition product into other substances. The following equa-
tions will give some types of these reactions:
+
(1) A + H+ Cl A.HC1
C1
(2) A + 2H
+
www.w
Frans
B+ H+ Cl;
+
+
tutm
++
A.2H
+
A.H₂C1
WWOH
+
(3) A + 2H + C1
+
STOR
B+ 2H;
+
B+ 2H + C1;
(4) A + 2H + 2C1+ B
WOM
TWOW
MISHIE
A.2HCl + B
(5) A + 4Cat + B A.4Cat+B
+
C + 2H + 2C1;
MAM
Makkal
C + 4Cat.
The first two reactions will increase in velocity directly in
100
proportion to the square of the concentration of the hydrogen
ions, the velocity of the third reaction will increase in propor-
tion to the third power of the concentration of the hydrogen
ions and the velocity of the fourth and fifth reactions will
increase in proportion to the fourth power of the concentra-
tion of the hydrogen ions or catalyzer.
(4) The third law of catalysis cannot hold in those reversi-
ble reactions in which the velocity of one reaction is accelerated
in proportion to the m power of the concentration of the cata-
lyzer while the velocity of the reverse reaction is accelerated
in proportion to the n power of the concentration of the cata
lyzer. It is assumed, here, as in (3), that only very small
amounts of the catalyzer unite with very small amounts of
some other substance and that the addition product then under-
goes further transformation.
As an illustration let us consider the following equations:
+
+
A+ mH + B
→
+
A.mH + B
C + D +mH
and
(1)
A + B + nĦ. (2)
C+D+nĤ ⇒ C.nĤ+D
The velocity of the reaction can be represented by the equa-
tion (3)
dx
dt
K(C₁—x)(CB—x)C — K' (Cc + x) (CD +x)C¾¼4• (3)
m
H
When equilibrium is established we have
K(CA-x)(CB-x)CH K'(Cc + x)(CD + x)CH
or
K(CA-x)(Cв — x)
B
K' (Cc+x((CD+x)
རྔུལ་ རྗབ
CH
cn-m
(4)
CH
There was a mistake on page 412 in the article¹ by
m
Acree and Johnson in that the term (Cat)n was by an over-
¹ Am. Chem. J., 37, 410.
IOI
1
cat
~n-m
H
sight inserted instead of the expression Cm. Since C
in (4) varies with the change in the concentration of the hy-
drogen ions it is evident that the equilibrium between A, B, C
and D must vary with the change in the concentration of the
ions. In the work on esters n-m becomes zero and C-be-
comes unity, and the equilibrium is not appreciably changed
by a change in the concentration of the catalyzer. It is evi-
dent that when n and m are equal, but not unity, the third
law of catalysis holds, but the second does not.
H
The discussion in the preceding sections applies equally
well to the reactions in which negative catalysis takes place.
It is perfectly evident that the velocity of certain reactions,
reversible or non-reversible, could be decreased because the
catalyzer combines with some constituent of the reacting sys-
tem and hence causes a decrease in the concentration of that
constituent. The conditions for negative catalysis would be
fulfilled if the addition product does not react directly with
the other constituents, but is always in equilibrium with the
catalyzer and the other component of the addition product,
which component does react with the other constituents.
The negative catalysis of the reaction between the phenyl-
thiourazole anion and ethyl iodide by the hydrogen ions of
hydrochloric acid is a very good example. The hydrogen
ions unite with some of the phenylthiourazole anions, decrease
the concentration of the phenylthiourazole anions and hence
lower the velocity of the reaction. Since the phenylthio-
urazole formed, however, is always in equilibrium with the phen-
ylthiourazole anions and the hydrogen ions, the reaction is
not stopped short of completion at all, but only made slower.
The general ideas discussed in the four preceding sections
apply equally well to the formation of this non-reactive ad-
dition product, and hence to the negative catalysis by acids,
bases and salts.
In the above discussion of catalysis no attention has been
given to the consideration of the catalytic action of finely
divided metals, or other substances, nor to the reactions brought
about by enzymes.
Both the metals¹ and enzymes probably
¹ Stock, Gomolka and Heynemann: Ber. d. chem. Ges., 40, 532. Stock and Boden-
stein: Ibid., 40, 570. Rowe: Z. physik. Chem., 59, 41.
102
have the power of condensing the reaction substances on their
surfaces and hence increasing the reaction velocity on account
of this increase in concentration of the substances. Of course
the enzymes and metals probably have also specific chemical¹
catalytic action. These cases in the study of catalysis will
be reported on later, in more detail.
The ideas advanced concerning the catalysis by acids hold
just as well for reactions influenced catalytically by bases and
metallic alcoholates.
Conclusions.
1. Work on the reactions between urazoles and alkyl
halides, on the rearrangement of acetylhalogenaminobenzene
derivatives, on the reactions of carbonyl compounds with
hydroxylamine and phenylhydrazine, on the inversion of cane-
sugar, on the hydrolysis of amides, and on the formation and
saponification of esters teaches us that acids, bases and salts
may act as positive or negative catalyzers and cause a change
(increase or decrease) in the velocity of a reaction because they
bring about changes (increase or decrease) in the concentra-
tions of the particular ions or molecules entering into the re-
action.
2. The study of the rearrangement of acetylchloramino-
benzene has shown that the second law of catalysis given above
does not hold in all catalytic reactions.
3. The study of the reactions of carbonyl compounds with
hydroxylamine has shown that the third law of catalysis given
above does not hold in all catalytic reactions.
4. A general discussion of catalytic reactions has shown
why the three so-called laws of catalysis given above were
deduced from the experimental material, and under what con-
ditions they do or do not hold in catalytic reactions.
1 Acree and Hinkins: Am. Chem J., 28, 370.
BIOGRAPHICAL.
James M. Johnson was born in Newberry, South Carolina,
August 15, 1883. His early training was received at the
Newberry Graded Schools. He entered Newberry College
in September, 1897, as a sub-Freshman, and graduated from
that institution with the B. S. degree in 1902, and with the M. A.
degree in 1903.
He has taught as follows: Assistant in Chemistry, Newberry
College, 1902-3; Principal, Newberry Graded Schools, 1903-4;
Carnegie Research Assistant in Johns Hopkins University,
1906-7; Lecture Assistant in Johns Hopkins University
during 1906-7.
In October, 1904, he entered the Johns Hopkins University
as a graduate student in Chemistry, his subordinate subjects
being physical chemistry and mathematics.
1
AUTHOR
TITLE
BOOK CARD
CALL NO
Q I
Johnson, J. M. 567
Studies in Catalysis...
SIGNATURE
DUE
ssued
2990 20
Medical Library
Medical Library
UNIVERSITY OF MICHIGAN
3 9015 07709 6363
1
1
}