Hanson tJames &radlei t . f\ Study of Decom position Proce sses Applicable to Certain Products of Coal Car bonizat,o n . ' A STUDY OF DECOMPOSITION PROCESSES APPLICABLE TO CERTAIN PRODUCTS OF COAL CARBONIZATION BY MANSON JAMES BRADLEY A. B. McMaster University, 1915 A. M. McMaster University, 1915 THESIS Submitted in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY IN CHEMISTRY IN THE GRADUATE SCHOOL OF THE UNIVERSITY OF ILLINOIS 1921 if University of Illinois Library Manuscript Theses Unpublished theses submitted for the Master’s and Doctor’s degrees and deposited in the University of Illinois Library are open for inspection, but are to be used only with due regard to the rights of the authors. Bibliographical references may be noted, but passages may be copied only with permission of the authors, and proper credit must be given in sub- sequent written or published work. Extensive copy- ing or publication of the thesis in whole or in part requires also the consent of the Dean of the Graduate School of the University of Illinois. has been used by tures attest their acceptance of the above restric- tions. A Library which borrows this thesis for use by its patrons is expected to secure the signature of each user. This Thesis s NAME AND ADDRESS DATE 0 ': , . 21 nz UNIVERSITY OF ILLINOIS THE GRADUATE SCHOOL May 10, i 9 £1 I HEREBY RECOMMEND THAT THE THESIS PREPARED UNDER MY SUPERVISION BY Mans on James Bradley ENTITLED M A Study of Decomposition Processes Applicable to Certain Products of Coal Carbonization. ” BE ACCEPTED AS FULFILLING THIS PART OF THE REQUIREMENTS FOR THE DEGREE of Doctor of Philosophy in Chemistry IaT Jl. In Charge of Thesis Head of Department Recommendation concurred in* Committee on Final Examination* *Required for doctor’s degree but not for master’s Digitized by the Internet Archive in 2015 https://archive.org/details/studyofdecomposiOObrad 1 . ACKbTOWLEDGSiUENT The writer wishes to express his sincere thanks to Prof. S.W. Parr, whose suggestions, assistance, guidance and encouragement made this thesis possible. Deep appreciation is felt for the valuable training in the fundamentals of research. It is expected that this stimulated appreciation of chemical investigation will increase with time because research is appreciati on . He also wishes to thank Dr. T.E.Layng, not only for help and instruction in assemblying the apparatus, but more especially, for the .many valuable suggestions and advice during the investigation. Table of Contents 2 . I. INTRODUCTION. 1. Preliminary 2. General Considerations. 3. Scope of Previous Investigations 4. Outline of Present Investigation 5. Grouping of results of the Investigat ion . II. EXPERIMENTAL WORK. 1. Apparatus 2. Method of Operation 3. Method of Analysing products 4. Specification of the Hydrocarbons used in the investigation. 5. Preliminary Runs. 6. Series of Runs using Charcoal surfaces. 7. Series of Runs through Iron Furnace 8. Series of Runs using Copper lining in the Furnace 9. Series of Runs using Tinned-Copper Lining in the Furnace 10. Series of Runs using Refractory Lining in the Furnace. 11. Series of Runs using Benzene 12. Series of Runs using Toluene 13. Series of Runs using Naphthalene. III. SOME PRODUCTS SYNTHESISED IN THE INVESTIGATION. 1. Gases, 2 Liquids, 3 Solids. IV. SUMMARY. V. BIBLIOGRAPHY 3 4 10 15 17 19 21 22 23 23 25 37 42 50 62 73 73 74 76 63 85 VI . VITA. 66 3 . A STUDY OF DECOMPOSITION PROCESSES APPLICABLE TO CERTAIN PRODUCTS OF COAL CARBONIZATION. 1. INTRODUCTION. I. PRELIMINARY. In undertaking a complex investigation such as that of the reactions occuring during the decomposition of the products of coal carbonization, there are two principal procedures to follow. One might take the crude material in all its complexity, decompose it under diversified conditi ons , and, by the careful examination of accurately recorded result s , endeavor to arrive at definite conclusions, the validity of which could be established by further observati on , or by modifying details in the direction indicated. This is the intelligent and progressive practice fol- lowed by industrial concerns. Alternatively, one might try to arrive at a better understand! ng of the intricate complex by a preliminary study of single c onsti tuent s , determining, for example, the mode of formation and decomposition of some one constituent of coal carbonization under a variety of conditions, including, as of primary importance, those conditions to which it would be subjected in carbonizing practice. This method is particularly suited to the laboratory and is the principle underlying the following investigation. Even the study of the decomposition of a single constituent becomes very complex when we take into consideration, the factors that influence equilibrium in any gaseous chemical reaction. Among these factors, temperature, pressure, concentration or mass action, 4 duration of time of contact or reaction, and contact surfaces are of prime importance. Several of these factors, such as temperature control, may he suh-divided into a number of problems, each of which may be very difficult of solution, especially if it is desired to construct large scale apparatus for the commercial production of these decomposition products. 2. GENERAL CONSIDERATIONS. True equilibrium, that state in which reactions pro- ceed equally in each direction, is seldom attained in any hydrocarbon decomposition. Under constant pressure there is a definite proportion, of the individual constituents for each temperature; under constant temperature there is a definite proportion between the reacting constituents for each pre s- sure, even if the numerical value of the equilibrium constant is a function only of temperature. Heat can supply the energy necessary to change an existing state of chemi- cal inertia and cause reaction between the various molecu- lar formations but too high a temperature, during an extend- ed period of time, permits the hydrocarbon to decompose into carbon and permanent gases. The father the system is from * stable equilibrium the greater the tendency for reaction to take place. Changing the temperature may bring the system nearer to the desired equilibrium point. No single equili- brium, however, can be considered by itself because all the constituents must also be in equilibrium, or a system of 5 . equilibria between all the components of the system. In an unbalanced system of gases there is a tendency for an equilibrium to be established between all the components of that system. All the reactions that occur in a hydrocarbon process are interrelated and must be taken into considerati on even if a single reaction or set of reactions may be ex- tremely important as indicating a prevailing tendency. The decomposition of hydrocarbons increases with rise in temperature and with the duration of time in the heated zone. Le Chatelier’s theorem predicts that an increase in temperature will drive the reaction in the direction in which heat is absorbed. Thus heavy molecules are less stable than lighter ones of similar structure. Indications of the effect of temperature on decomposition processes may be obtained from thermodynamics. Bertholet advanced a proposition which c.: n be summarized as follows, - every chemical change gives rise to those substances that occasion the greatest development of heat. If this were true, the problem of obtaining temperature indications would be as simple as that of obtaining pressure indications for reactions proceeding to equilibrium. That proposition, however, is only a first approximation, because in all chem- ical reactions there is additional molecular energy, where- as the proposition mentioned assumes the free energy, termed maximum work, to be equal to the total energy change. Nernst has pointed out that this statement holds true only at the absolute zero; that is, the entropy of liquids and ■ I - . • . t, I ' , - - * ' • ’ i •• , 6 solids at absolute zero of temperature equals zero. The temperature most favorable for the production of the largest quantity of any particular aromatic hydrocarbon is quite different from the optimum temperature for the formation of a higher or lower homologue. The temperature best suited to the formation of naphthalene is quite different from that required in the formation of benzene and as we approach or depart from this optimum temperature the yield of the desired hydrocarbon increase or decrease proportionately. When considering the effect of pressure on a gaseous system similar difficulties are encountered as in the case of temperature. The application of Le Chatelier's principle shows that pressure favors any reaction resulting in decrease in volume and opposes any reaction that is accompanied by an increase in volume. Stated in another way, diminished pressure, increases decomposition of hydrocarbons or increases the for:jation of gas, while increase in pressure decreases decomposition or tends to form liquid and solid compounds. It appears possible, therefore, to obtain indications of the effect of pressure by simply writing the chemical equation and summing up the volume changes. However, it must be remembered that pressure produces a change in the concentra- tion of the reacting substances, which may produce a marked change in the reaction of constituents in the system. Accord- ing to the law of mass action, the velocity of a chemical 7 . reaction, at any small intervals of time, is proportional to the amount or concentration of substance undergoing transformation at that time. So an increase in pressure may promote decomposition or chemical change rather than retard it, because of the additional variables unavoidably introduced at the same time, thus defeating the result de- sired . The duration of time of reaction is a very import- ant factor in any gaseous decomposition. It is intimately related to the temperature, pressure, gaseous constituents and end products desired. Organic reactions seldom come to equilibrium instantly but required a definite time inter- val. This time interval, in hydrocarbon decompositions , can be controlled in several ways, the two easiest manipulated, are lengthening or shortening the heated zone, or by increasing or decreasing the rate of feed through the heated area. Obviously a high temperature will require a lesser time of contact, than a relatively lower temperature. A slow rate of feed and a relatively low temperature will accomplish practically the same results as a relatively faster rate of feed at a much higher temperature, with the single difference that more time will be necessary for a given quantity. The effect of contact surface is perhaps the most indefinite and most important variable in any hydrocarbon decomposition process. The phenomena of catalytic acceler- ation or retardation of physical or chemical processes are so common as to defy systematic classification, since such a complete system would necessarily include all possible types of reactions, both homogeneous and heterogeneous. Ostwald's often quoted statement, - "There is probably no kind of chemical reaction which cannot be influenced cata- lytically and there is no substance, element, or compound which cannot act as a catalyser", - indicates the comprehen sive susceptibility of catalysis. Many theories have been propounded to explain the mechanism of catalytic reactions. Faraday's concept of catalytic activity being due to selective adsorption phenomena was advanced by J.J. Thomson 1 coupled with La- o place's theory of capillarity. Bancroft's latest state- ments, that selective adsorption permits. of different reac- tions being accomplished with the aid of different cataly- tic materials, emphasis two important details, namely, 4 catalysts tend to produce the system which they adsorb most strongly and the compound or adsorptive layer may be regarded as a solvent and hence may exert an influence on the final equilibrium. Sabatier*’ , after many years spent in investigation with nickel catalysts in hydrogenation processes, came to the conclusion, that the formation of an intermediate com- pound with the catalyst and reacting substance, was the best explanation for this extraordinary activity. In many 9 organic catalytic processes, such as the formation of ether, Fri edel-Crafts reaction, Qrignard reagent and many others, the intermediate compound can he isolated. An extremely interesting modification of this theory was advanced hy Armstrong. To him, chemical combination is reversed electrolysis, and the function of the catalyst is to form a circuit containing a t least three distinct terms or com- ponents analogous to a closed voltaic circuit. By this means the catalytic agent collects into one system the various elements necessary for a particular chemical change, and may he said to form molecular complexes with the reactants. A recent theory of catalysis, somewhat of an electro- 5 6 chemical nature, has been advanced hy Langmuir and Harkins. i According to Langmuir, the adsorbed film, which is hound to the adsorbing surface hy chemical forces, namely, the primary or secondary valencies, should he only one molecule thick and in this layer there exists an orientation of the mole- cules. He has developed this general theory of adsorption to the particular case of the adsorption of gases hy plane, solid surfaces, and gives the results of a series of ex- periments on the adsorption of various gases hy sheet plati- nuffi, glass, and mica at low pressures and various tempera- tures. This theory takes into account directive as well as selective adsorption, thus bridging the gulf between the theory of the intermediate compounds and the purely adsorption idea, since the postulate of directive force necesss.rily 10 assumes some form of chemical union between the contact surface and the molecules of the surrounding medium. These theories are discussed by E. Rideal and S. Taylor in their recent text, "Catalysis in theory and practice". 3. SCOPE OF PREVIOUS INVESTIGATIONS. In the following resume on pyrogenetic reactions of aromatic hydrocarbons only those investigations that seem most important in connection with the present problem are mentioned. Much work has been done on the problem of thermal reactions of aromatic hydrocarbons, but, on ac- count of the many variables encountered, no systematic study of these reactions have appeared in the literature. 7 The historical researches of Bertholet have furnished a foundation for succeeding investigations with pure aromatic hydrocarbons. His work was comprehensive and the results obtained very valuable. He passed the vapors of pure hydrocarbons through "red hot tubes" and obtained the general results as follows: from benzene he obtained diphenyl, chrysene and resin; from toluene he recovered benzene, toluene, naphthalene, anthracene and chrysene; from xylene he collected benzene, toluen^ xylene, nap- hthalene, and anthracene; while anthracene yielded benzene and chrysene. Prom the mixed vapors of naphthalene and benzene he obtained anthracene and from benzene and ethy- lene he recovered anthracene and diphenyl . Ho yields of products are reported in these publications and the temper- ature designated by the term "red-hot" is very indefinite. . . • ■ . ' ■ , ' ■ - . . . ■ . Recently, ZanetiA and Kendall have studied the pyrogenetic production of anthracene from henzene and ethylene in a quantitative manner and at various tempera- tures. They bubbled the ethylene through the benzene and passed the vapors through a hhated quartz tube. Their best yield, (0.675$ from the total benzene used), was obtained o at 925 C and at atmospheric pressure. At this temperature the sum of the yields of diphenyl and carbon is a minimum and above it the formation of carbon occurs very rapidly. In some previous experiments conducted by Za.netti 9 and Egloff, on the thermal decomposition of benzene with catalysers, they found that benzene could be decomposed to diphenyl at a temperature as low as 500° C. but did not believe that copper iron or nickel gauze inserted in the craking tube, catalysed the reaction. However, iron and nickel did seem to catalyse the reaction to carbon and hy- drogen . Some valuable information indicating the direction of reactions in the thermal decomposition of hydrocarbon vapors was obtained by Eerko^ by passing the vapors through a "red hot” iron tube. The temperature he used was very indefinited and the pressure is not mentioned, no doubt, the results given are at atmospheric pressure. From benzene and ethylene he recovered benzene, stryolene, diphenyl, phenanthrene and anthracene; from toluene he obtained ben- zene and anthracene; while from toluene and ethylene he iden 12 tified benzene, toluene, stroylene and anthracene. These results show that no reaction products were obtained that were not in the order of decrease of saturation or of mole- cular weight if the saturation remained unchanged. That is, benzene yielded no toluene nor any other compound of equal saturation and of greater molecular weight. Naphthalene gave neither benzene or toluene but small amounts of dinaphtha- lene and phenanthene. Prom Haber’s 11 work on the thermal decomposition of hydrocarbons he found that benzene decomposes with difficulty above 900°C and although it goes readily to diphenyl and hydrogen no naphthalene is formed. He concludes that in aromatic hydrocarbons decomposition takes place between carbon and hydrogen atoms. 1 p In some qualitative experiments by McKee in which he passed benzene vapors through a copper tube at tempera - o o tpres ranging from 450 C to 785 C, he concluded that the order of hydrocarbon decomposition is as follows* higher paraffines — » lower paraffins — ^ Olefins — » acetylenes — * benzene and homologues — » diphenyl — * naphthalene , etc . — » tarry matter — » carbon and gas. No analysis or separation of the products was attempted, he merely determined the degree of decomposition by the change in the specific gravity of the product. 13 Ipatieff found that benzene decomposed with the liberation of hydrogen, forming diphenyl above 600°C. 14 Ostromisslenske and Burshanadse found that when benzene vapor was passed over nickel or nickel oxide at temperatures of 600° to 750° C, carbon and hydrogen were the main products. 1 5 Siiiith and Lewcock passed benzene vapors through an iron tube containing different catalysers such as barium oxide and coke, and found that diphenyl was not formed below 670°C. but at 800°C. they obtained a 25 % yield of diphenyl. They could not reverse the reaction, and noticed that the yield of diphenyl increased with the rate of feed , indicating that diphenyl was an intermediate, rather than an equilibrium product . i (i Rittrnan,Button and Dean -1 * in their pyrogenetic decomposition of aromatic hydrocarbons, in the vapor phase, passed benzene, toluene, xylene, naphthalene and anthracene through iron tubes at temperatures ranging from 650° to 800°C and from diminished pressure up to pressures of 18 atmospheres. They also came to the conclusion that the course of the reaction is in the direction of the decrease in the size of the molecule, when the degree of saturation remains unchanged. Dehydrogenation, either with an increase or decrease in the size of the molecule, may occur but the reverse reactions are negligible. 17 Charlton made three distillations olf xylene at temperatures between 600°C and 700°C through an iron tube containing charcoal, also with charcoal impregnated with nickel, in the presence of superheated steam, to determine the relative yields of toluene and benzene. At 650 °q q n ^ atmospheric pressure, when using nickel charcoal catalyser, 14 . the recovered "benzene equalled 0.33$, and the toluene 0.40$, while the higher boiling fraction equalled 4.56$ of the toluene used. Another experiment at the same temperature using the same catalyser but allowing the superheated steam to build the pressure up to 40 pounds per square inch, pro- duced 0.958$ benzene, 3.6$ toluene and 9.12$ higher boil- ing compounds. When running under 110 pounds pressure the yield of benzene increased to 1.45$ but the other products became less. It is interesting to note that at atmospheric and 40 pounds pressure no paraffine hydrocarbons were obtained but as high as 28.0$ unsaturated aliphatics were found in the product. At 110 pounds pressure the unsaturated com- pounds were reduced 100$ while 10.0$ of paraffines were obtained. In the high boiling oils, monomethyl anthracene separated out but no naphthalene was found in any of these experiments . 1 8 In the researches of Cobb and Dufton, on the thermal decomposition of pure aromatic substances, benzene, toluene, xylene, and cresol, were vaporized and passed through a silica tube containing coke at various tempera- tures, in the presence of hydrogen or nitrogen and the de- composition products collected and analysed. These results are the most important of any published along this line. They found that benzene could be stabalized at temperatures of 750°C by having the gaseous mixture consist of 93 per . ( 15 cent hydrogen. Under low concentrati ons of hydrogen diphenyl was formed. They proved that the diphenyl formation was an equilibrium reaction by saturating hydrogen with diphenyl vapors at 90°C and passing the mixture through the tube at 750° and obtaining benzene. From toluene they recovered benzene, ditolyl and anthracene and from xylene they obtained benzene, toluene, diphenyl, and anthra- cene. These results are given on a quantitative basis to- gether with much other valuable information. 4. OUTLINE OF THE PRESENT INVESTIGATION. The object of the present experimental work, broadly stated, was to determined the effect of various combinations of temperature, pressure, concentrati on , and contact surfaces on the course of decomposition reactions of aromatic hydrocarbons, in the vapor stage, and to determine, if possible, the most favorable conditions for the maximum yield of the various desired decomposition products, such as benzene, toluene or anthracene. In the extensive experimental work carried on in these laboratores on the coking of Illi- 19 nois coals.’*' Utah coals, and xaany other varieties, it has been found possible to increase the quantity of tars and oils produced from two to four fold, by means of low temperature carbonization. The distillate obtained, in this manner, contains a large quantity of neutral, low boiling 16. 1 aromatic oils, some of which, under noruial commercial con- ditions, are considered of little irn.ports.nce in the industrial field. For instance, xylene in its present status, is a product scarcely worthy of recovering and purifying, yet by application of known methods of recovery, could be produced, under present conditions, in enormous quantities. This hy- drocarbon, having a boiling point of 137 to 141 C has too low a vapor pressure for an efficient motor fuel, however, if by methods of pyrogenic decomposition, it can be converted into benzene, which has a boiling point of 80°C, its value as a motor fuel is greatly increased. If this decomposition can be accomplished, in yields, approaching anything like theoretical and in commercial quantities, the hydrogen and methane li oerst- ed ought to more than supply the heat energy required in the operation. Xylene can be decomposed with anthracene as an end product, but under existing methods the yield is small. If this dec omposit ion could be made on a commercial scale and in yields sufficient to warrant its use, one of the main props in the synthetic dye industry would be assured. 3ver since 1856 when Perkin produced the first alizarin dye from anthracene , the increase in production of this hydrocar- bon has been eagerly sought. During the last few years it has been demonstrated how important the dye industry in this country has become. In this investigation pure xylene was passed through an electrically heated furnace, at various temperatures, 17 different rates of feed, under various pressures, in the presence of such contact surfaces as iron oxides, reduced iron, copper, tin, molybdenum, chromium, Illuiin, aluminium, nickel, cobalt, manganese, charcoal, pumice and refractory, the condensable compounds collected, weighed and analysed, also the gas was measured and analysed. Hot only was the above variables tried out but the vapor condition inside the furnace was in- fluenced by passing in at the same time as the hydrocarbon , air , superheated steam, carbon dioxide, carbon monoxide, hydrogen, nitrogen or ethylene. 5. GROUPING OP RESULTS OP THE INVESTIGATION. The facts established by this investigation rnay be brieflj' - summarised as follows: (1) Mixed xylenes were decomposed by heat and contact sur- faces, under the stabilizing influence of hydrogen and methane, almost theoretically into benzene and methane. Sixty-nine percent of the original xylene was convered into crude benzene, which boiled below 100°C . This is approximately 94.0 percent of the possible theoretical. (2) At slightly lower t emperatures , under the same con- ditions of contact surfaces, but in a gaseous atmosphere in which ethylene greatly predominated, seventy-seven percent of the mixed xylenes were built up into higher boiling com- pounds, the majority of which were solids at ordinary temper- atures . (3) Mixed xylenes, under other conditions of temperature and contact surfaces, were converted into crude toluene, in 18 quantities approximating 64.0 percent of the possible theoreti- cal . (4) Mixed xylenes, under the influence of heat and iron surfaces, were decomposed quantitatively into amorphous carbon and gaseous products. Small particles of iron oxides and reduced iron were found in the deposited carbon. (5) Activation of heated iron and carbon surfaces could be induced by treating with superheated steam during a short period, and afterwards slightly reducing with hydrogen. (6) A deadening effect, opposite in characteristics to the above, was caused, when carbon dioxide, carbon monoxide, air or superheated steam was passed through the activated fulrnace. This condition seemed to be the same as is ordinarily described, as poisoning of the catalyser. (7) The decomposition of ethylene was controlled so that practically pure methane, or mixtures of methane and ethane were obtained as end products. (8) The following gaseous products were synthesised from mixed xylene: Ethylene, methane , ethane , acetylene and carbon oxides. (9) among the liquid products synthesised from mixed xylene:- n-hexane, cyclohexane, benzene, toluene, ditolyls, methylnaphthalene, and diphenyl ethane have been identified. (10) The solids synthesised from mixed xylenes contained diphenyl, naphthalene, stilbene, methyl anthracene, p-diphenyl benzene, anthracene and methy derivitives. 18A 19 II. EXPERIMENTAL WORK. 1. APPARATUS. The essential parts of the apparatus are shown in the accompanying photographs and drawing. The complete outfit, being of a conventional type, requires little explanation with the possible exception of the furnace. It was made by taking six feet of four inch, Ho. 18 Byer's pipe, threading on flanges and thermo couple pockets and then having these joints acety- lene welded to insure having no leaks under conditions of high temperature and pressure. The caps were cast particularly for this furnace and extended l-g- inches into the end of the pipe and were fitted with three, three-quart er-inch threaded open- ings leading into the furnace. The pipe was thinly coated with alundum cement; wound in five sections, each having 36.5 feet Ho. 1.4A chrorael resistance wire and again coated with cement. It was surrounded by a wooden box twenty inches square and as long as the furnace, which contained the pulverized asbestos and Sil-O-Cel insulation. Each, heating element, when connected directly across the 110 volt line, allowed a maximum current of 20 amperes to pass through but this could be reduced to 5 amperes by means of an external resistance connected in series at the switch board. At no time was more than 10 amperes allowed to go through the heating elements. By this means the heat of the furnace could be kept constant at any desired 20 . temperature between 250 and 900 C. The top end was fitted with feed pipes for xylene, superheated steam and other gases, also with a pressure and reduced pressure gauge. On the exit at the bottom end was a safety relief valve, or constant pressure valve, which could be adjusted to let the gases ex- cape into the line, leading to the gas meter, at any desired pressure. This outfit has been operated under 180 pounds pres- sure per square inch. The temperature was measured by means of a thermocouple made from six feet of No. 8 Chromel s-nd alurnel wire. The cold junction was kept at zero by means of a thermos bottle well and ice water, the e.m.f. was read on a millivoltmet er which had been standardized at knownt empera- tures. By this method the temperature could be read accurate- ly within four or five degrees. The thermocouple pockets (k) extended into the middle of the furnace and thus gave the temperature of the area where the largest volume of vapors passed . EGA Pig. 1. Upper end of Furnace 2 OB Fig. 2. Lower end of furnace 21 . 2. METHOD OE OPERATION. The mechanical arrangement of the apparatus is appar- ent from the explanation of the progressive steps of a typi- cal run. The xylene was placed in the reservoir (A) fed hy means of a regulating valve through the sight-glass, or by- pass (B) into the upper end of the furnace (C). Here also, could he introduced gas, such as hydrogen, nitrogen, carbon dioxide or ethylene from the cylinder (I), or from the high pressure steam line (J) through the gas-fired superheater (H) could be introduced steam. Another attachment, not shown in the picture, permitted the use of compressed air. In passing down through (C) the vapors came into contact with the various contact surfaces used. The highest boiling condensate was collected in receiver (i) the medium oils in No. (2) while the gases, after passing through the water cooled con- densers (D) were scrubbed with heavy oil in receiver (3). The gas leaving receiver (3) passed through pipe (E) to be meas- ured by the meter ( E) and was then burned, or analysdei by means of the modified Orsat apparatus (G). When run- ning under increased pressure, extra lengths of piping, fitt ed with a gate valve, were attached to the ends of the condensers By keeping the lower valve closed and the upper one open, tne condensate collected between them and could be. easily removed, by closing the upper valve and opening the lower one, without causing any change in the pressure within the furnace. . , ■ • : • * • 4 22 . 3. METHOD OF ANALYSING PRODUCTS. The condensable products were weighed, fractionated through a six-inch wash column of glass-beads, until all the o liquid boiling below 145 C was removed. The liquid boiling above 145°C, designated in the following experimental results as high boiling product, was then transferred to an ordinary pyrex distilling flask and the fractionation continued until all but coke was driven over. These operations were performed by means of electrically heated furnaces similar to those 17 fully described by Charlton. The solids obtained from the high boiling oils were purified and analysed by a combination of various methods, 1 7 pi op as described by Charlton, , Clark , Cook^~ and others. These will be fully explained in a succeeding thesis now being prepared in these laboratories by Mr. Malecki. The non-condensable or gaseous products were analysed by means of a modified Orsat apparatus which has been con- structed in these laboratories. A full description of this apparatus will be submitted for publication to one of the technical journals. The carbon dioxide was removed by 35% potassium hydroxide; oxygen by potassium pyrogAllate; acetylene by ammonical silver chloride; ethylene by bromine water; aromatics by 20% fuming sulfuric acid; hydrogen and carbon monoxide by combustion at 28©-300°C with copper and ceric oxides; ethane and methane by slow combustion in pure oxygen; while the nitrogen was estimated by difference. It is realized 23. that an exact separation of acetylene and ethylene cannot he obtained in theabove manner but by leaving the gaseous mix- ture in contact with the ammonical silver chloride solution during a constant time interval in each analysis, a relative idea of these two constituents can be obtained. A Complete analysis could be made in less than thirty minutes, except in cases where the carbon-monoxide content was high. Carbon mono- xide seemed to poison the copper and ceric oxides and thus greatly retard this combustion. 4. SPECIFICATION OF THE HYDROCARBONS USED IN THE INVESTIGATION. The mixed xylene, the commercial product put on the market by the Barrett Co. in 10 gallon tin cans, was used in the major portion of this work. It was water- white, contained no suspended material, was free from moisture, had no foreign odor, practically all distilled between 13? and 142°C, and had a specific gravity of 0.8664, at 15.5°C . The benzene, toluene and naphthalene used were the commercial products in stock at the chemistry store- room. They were not analysed or purified in any way. In fact, only a few runs were made with them, to try to check up on the results obtained from xylene, under similar conditions in the furnace. 5. RESULTS OF PRELIMINARY RUNS. By the term ’’run" is meant the operation of feeding 24 . a definite quantity of material into the furnace, at any desired temperature, during a constant time interval. Or stated in another way, feeding the material at a constant rate; this rate was changed to suit the other conditions hut was constant during any series of runs. After all the material had been passed into the furnace about thirty minutes were re- quired for the final traces of the condensate to drain out and the evolution of gas to be completed. In order to try out the effect of temperature and the iron furnace surface on the xylene a series of runs were made at atmospheric pressure, with 1000 grams of xylene, at each 50°C rise in temperature, between 200 and 600°C. Each run required one hour. In this series of nine runs, the loss was less than one percent, the gas given off was too small to warrant analysing, while the condensate proved to be almost entirely unchanged xylene. Naturally it was concluded, that the effect of the iron surface at various temperatures, was practically negligible and could, very con- viently, be neglected for all practical purposes in this in- vestigation. However, before the work had proceeded very far, this was found to be an erroneous conclusion. The iron sur- face could be " activated" or " deadened” in such a way as to produce diversified results. 6. SERIES OF RUN’S USING CHARCOAL SURFACES. 25 . This series of runs were to ascertain the effects of iron and charcoal surfaces under similar conditions as recorded previously. A piece of sheet iron, 3/16 inches thick and five feet long, which had been drilled with 5/8" holes 3/8" apart, was made into a tube, which fitted snugly into the furnace. In this perforated tube was placed approximately two kilos of wood charcoal, which had been cut into cubes between l/2 and 3/4 inch square. In these runs 1000 gms. of xylene was used as before. The first run was made at 250°C and in it the loss of xylene amounted to 4 percent. This was no doubt due to absorxjtion by the charcoal. *.3 the temperature was raised, more moisture was driven from the charcoal and the percentage of carbon monoxide in the gas increased. Below 450°C very little change was noted in the recovered xylene, or in the volume of gas given off. In fact, the total loss of xylene was only about one to two percent. The results of the runs above 450°C are shown in Table No. I. In this table, as in all the following, the analysis of the escaping gas is given first; then the total amount of gas given off in the reaction, expressed in cubic feet; then co. nes the loss, in weight percent of the original xylene used in the run and finally a partial distillation analysis of the recovered condensate on the same basis. These cuts 26 . are made at arbitrary temperatures best suited to the distilling flask and wash-column used. In closer analytical work, it was found that the maximum portion of the fraction passing over up to 105°C consisted of benzene, between 105 and 130°C to be toluene and between 130 and 145°C to be xylenes. Of the product boiling above 145°C, 375 grams was distilled from an ordinary pyrex distilling flask and per- centage boiling between different temperatures is shown in the summary. TABLE I Summary of runs through furnace, containing 2£ kilos of charcoal cubes. In each run 1000 gm3 . of xylene was used and required twc • hours to feed into the ; furnace. No . of Run 20 21 22 23 24 25 26 27 Pressure lbs. All At mo spheric Temperature C 450 500 550 600 650 700 750 800 Carbon Dioxide 6. 9 10.2 6.4 1.6 0.2 0.2 0.0 0.1 Oxygen 7.2 2.8 1.7 1.3 0.5 0.4 0.4 0.1 Acetyl ene 0.0 0.4 0.2 1.2 1.0 0.4 0.3 0.2 Ethylene 0.1 0.2 0.3 3.4 4.3 2.2 1.7 1.4 Aromatics 0.0 0.1 3.1 12.2 8.0 3.1 2.7 1.6 Hydrogen 2.6 10.8 19,2 37.0 61.1 50.6 45.0 45.6 Carbon Monoxide 2.2 7.4 0 . 6 1.7 1.8 0.2 0.7 0.9 Ethane 2.2 1.0 4.8 7.1 3.2 2.3 0.8 0.0 Methane 0.7 .9 12.6 23.9 19.2 25.7 39.4 48.3 Nitrogen 80.4 66.2 50.9 10.8 0.7 14.8 9.0 1.8 Total ga3 cu.ft. 0.2 0.2 0.2 1.0 2.3 6.9 8.4 8.0 Percentage Loss 6.0 2.0 5.0 7.0 22.5 23.5 34.0 50.0 Up to 105°C • • • • • • • • • • • • #tr #tr 13.0 5.0 105 to 130°C • • • • • • • • • • • • 15.5 16.0 8.7 130 to 145°C 94.0 98.0 95.0 93.0 73.5 54.0 19.4 24.1 Above 145 °C • • • • • • • • • #tr 4.0 7.0 16.2 12.2 145 to 175°C 11.2 175 to 225°C 3.8 225 to 300° C 24.6 300 to Coke 41.4 Coke 13.9 28 . o In the heavy oils "boiling "between 225 and 300 0 a white solid separated out on standing; while "between 300 and 400°C a yellowish solid was deposited; while above 400 C the product was a yellowish solid at ordinary temperatures. The fraction coming over around 450°C was a reddish tarry substance and the last traces driven off were dense red fumes. In all the above runs more or less water was found in the condensate. This may have been held mechanically by the charcoal, or the result of reduction of some oxides, probably iron oxides. The table shows very plainly the stability of xylene under these conditions, decomposition, in appreciable amounts o o commencing around 650 C while at 750 0 the yields of the desired products is maximum. It is also interesting to note the change in percentage of ethane and methane with temperature. Methane being much ,uore stablfe at higher temperatures. As would be ex- pected, the total loss and amount of gas produced increases with rise in temperature. The nitrogen content of the first analyses is high, owing to the fact that the gas coming off was not suf- ficient to sweep the entire outfit free from air. All gas samples #Note. In all gas analysis nitrogen is estimated by substract- ing the sum of all the constituents from 100. The abbreviation Tr. indicates a very small amount less than one percent. All distillation cut3 are given in weight percent of the original xylene used. * ' ' ■ * . ■ 1 i * , 29. j were taken when the run was about three quarters completed. It was supposed that the conditions within the furnace, at that time would he as near representative as possible for the run. The gas was always analysed directly before passing through the meter. That is, the constituent ratio was not changed by allowing the gas to be stored, during varying periods, over liquid, before analy- sing. When the series of runs were completed, the furnace was allowed to become cold and the cap removed from the exit end. The charcoal in the lower half of the furnace was entirely consumed, leaving a gray, fluffy ash; the top half did not seem to have been changed, except being somewhat more lustrous in appearance. Between the perforated tube and the walls of the furnace was a compact deposit of carbon, which made it somewhat difficult to re- move the inner tube. As the furnace had been kept at a constant temperature for a considerable time before each run, it was concluded that this deposit was not due entirely to higher temperature right at the walls of furnace but that the iron surface was in some way or other promoting decomposition of the xylene . The next series of runs were made over 2-g- kilos of char- coal cubes. These were cut in sizes varying from 3/4 inches to l/4 inch square. The larger size, being placed in the furnace near the inlet and the smallest at the exit end. By this means more surface was exposed to the outgoing vapors. The furnace was — — — — — - — — — — - — 3ur~ then closed and live steam at 125 pounds pressure was turned on to make sure that there were no leaks in the outfit. It was found out later that steaming the charcoal greatly modified its activity in decomposition processes. > 3T TABLE II. Summary of runs over 2 £ kilos of charcoal cubes, which had been subject to live steam at 125 pounds pressure, before the furnace had been heated up. 1000 gms. of xylene used per run requiring two hours. No. of Runs 30 31 32 33 34 35 36 Pressure lbs. Atm Atm Atm Atm Atm Atm Atm Temperature C, 550 600 700 665 625 600 550 Carbon Dioxide 0.9 1.4 0.9 0.0 0.1 0.0 0.0 Oxygen 4.4 6.0 0.2 0.3 0.1 0.0 0.4 Acetylene 1.6 0.8 0.8 0.7 0.9 0.5 0.3 Ethylene 1.8 3.0 0.2 0.1 0.0 0.0 0.2 Aromatics 0.7 12.6 1.0 1.4 1.0 1.0 1.0 Hydrogen 28.4 29.0 75.2 71.9 75.8 72.9 79.6 Carbon lion oxide 0.3 0.8 5.7 3.0 0.4 0.2 0.1 Ethane 20.5 0.0 6.7 1.2 1.8 0.0 0.0 Methane 12.6 32.0 6 . 6 21.5 18.4 24.1 17.5 Nitrogen 28.8 14.4 2.7 0.0 1.5 1.3 0.9 Total gas cu.ft. 0.3 0 .7 4.0 25.6 25.4 25.2 18.0 Percentage loss 4.0 38.7 100.0 100.0 100.0 84.5 Up to 105°C tr tr 6.5 • • • • • « • • • 10.0 105 to 130°C 25.3 15.0 1.0 • • • • • • • • • 3.0 130-145°C 72.5 77.7 49.8 • • • • • • • « • 0.0 Above 145°C 1.8 3.3 4.0 • • • • • • • • • 2.7 In run 30 it is interesting to note the amount of ethane formed .Also , these conditions seemed most favorable for the ' 52 production of the toluene fraction. As the temperature rose, the toluene fraction became less, while the hydrogen content of gas greatly increased. Near the end of run 52, the temperature fell rapidly to 655°C due to a different reaction taking place in the furnace. At the same time, a marked increase was noted in the gas produced while the condensate decreased. Runs 55,54, 55 and 56 were made on decreasing temperature conditions. As the table indicates, the destruction of xylene was complete, hydrogen, methane and carbon being the final products. As the temperature was lowered, to ascertain at how low a temperature this reaction would continue, some traces of condensate was obtained at 550°C. As the temperature decreased from this point the condensate in- creased. The current was shut off and the furnace openings closed, so that no air could enter the outfit. After standing for four days the furnace was again heated up, without any change having been made in any particular from the previous conditions, and a series of runs made as the temperature increased. This was to see if the xylene would be again completely decomposed to gas and carbon, and to ascertain, if possible, at what temperature this reaction took place. The runs made at 250,270,525,565,400,450 450 and 470°C indicated very little reaction and practically no change, or loss in the xylene. When the temperature of complete decomposition was reached hydrogen from a cylinder was intro- duced at various rates to see if it was possible to stabilize any of the products by means of excess hydrogen from another source. The results show that this was in a small measure possible. — i ■ 33 TABUS 3. Summary of runs over charcoal and deposited carbon, which had previously given no condensate. 1000 grams of xylene used per run, requiring one hour. Hydrogen introduced from cylinder at arbitrary rate. No. of Hun 45 46 47 48 49 50 Gas introduced • » • • • • H 2 H 2 H 2 Air Pressure (lbs) Atm . Atm 21 25 15 5 Temperature °C, 500 550 650 600 500 500 Carb ondi oxide 0.0 0.0 0.0 0.0 0.0 3.5 Oxygen 1.0 0.0 0.0 0.0 0.0 0.3 Acetylene 0.0 0.7 6.7 0.0 0.5 0.0 Ethylene 0.7 0.3 0.1 0.6 0.1 0.1 Aromatics 1.2 1.4 1.0 1.0 1.0 0.6 Hydrogen 82.0 80.0 65.6 67.6 74.8 69.9 Carbon .Ion oxide 0.7 0.1 0.3 0.0 0.0 5.1 Ethane 0.4 1.9 0.0 0.0 0.0 4.1 Methane 13.6 13.3 26.7 28.7 21.9 7.0 Nitrogen 0.4 2.3 0.0 2.1 0.0 9.4 Total gas cuu»t. 3.0 28.0 25.5 20.3 10.0 1.0 Percentage Loss20.0 100.0 77.6 77.0 30.0 66.0 Up to 105°C 1.0 • • • 2.0 tr . tr . • • • 105 to 130°C, • • • • ♦ • 20.4 23.0 53.0 • • • 130 to 145°C. 75.5 • • • • • • • • • 17.0 44.0 Above 145 C, 3.5 • • • • • • • • • • • • • • • 34 . Huns 45 and 46 corresponded to the results of the previous series. Runs 47, 48 and 49 were made under the same conditions with the exception that hydrogen was added from a cy- linder, in a rapid stream, calculated to keep the atmosphere in the furnace, principally hydrogen. This gave conditions best suited to the formation of the toluene fraction. It would have been interesting to carry this investigation further under these conditions hut so much xylene had been decomposed that the furnace was plugging up with deposited carbon. At this point 8 cubic feet of air was passed through the furnace, while heated to 500° to see if some of the carbon could be oxidized and thus removed. Several analyses were made on the issuing gases and as high as 12.0$ carbon dioxide was found. It was soon demonstrated that this method of carbon disposal was too slow, so the air was discontinued. Run No. 50 at 500°C was with pure xylene, but the furnace was so filled up with carbon that it required a pressure of five pounds, built up from the decomposition of xylene, to force any gas through. It can be plainly seen that some marked change had taken place in the furnace. No toluene was obtained and all the condensate collected proved to be unchanged xylene. In other words, the oxygen and possibly the nitrogen also, had poisoned or slowed down the activity of the furnace. It was found by other methods that charcoal, after being heated to the nei ghborho od of 700 C allowed to cool, out oi contact with air, would take up air very rapidly. By again heating, the oxygen came off slowly in the form of carbon oxides, the dioxide • . • . • . , ■ ■ . « ■ • • ' . , ' • . ' ■ • ■ . . ' * 35 being given off at lower temperatures and as the temperature increased, carbon monoxide was the chief product. It is doubtful, if all the oxygen taken up could be driven off at temperatures of 700°C even in the presence of hydrogen. Diminishing amounts of moisture, being driven off, even after the treatment had continued several days. At the end of these runs, the furnace was so firmly plugged with deposited carbon, that it was impossible to remove the perforated tube containing the charcoal. In fact, this had to be broken into pieces to be taken out of the furnace. The next series of runs was made with a view of increasing the toluene fraction. As before, charcoal cubes were prepared and placed in the furnace by means of a tube made from ordinary brown wrapping paper. The gradation in size in the charcoal cubes was the same as previously and the same quantity used. While heating the furnace, hydrogen $as introduced, to try to reduce all oxides at temperatures as low as possible. As previously, moisture and a rancid smelling liquid was driven off the charcoal as the temperature increased. In this series of runs the rate of feed was decreased to 500 gms. of xylene per hour. At lower temper- atures no appreciable change took place, and only in the neigh- o _ borhood of 500 C were any results obtained worth tabulating. 36 Table 4. Summary of runs over 2 kilos charcoal placed in furnace by means of paper tube, 1000 gms. xylene used per run, fed at the rate of 500 gms. per hour. Furnace had been heated under reduc ing conditions. Results of high boiling fraction was obtained from 225 gms. product of the series. No. of Run s 53 54 55 56 57 58 59 60 Gas Introduced H2 H 2 « i • • • • • • « IT 2 • • • St earn Pressure Lbs. Atm Atm Atm Atm Atm Atm Atm Atm Temperature t. 600 650 625 650 700 750 750 750 Carbon Dioxide 1.3 0.5 110 0.0 0.0 0.0 0.0 20.2 Oxygen 0.3 0.1 0.6 0.5 0.1 0.1 0.0 0.0 Acetylene 0.3 0.1 0.8 0.3 0.1 0.3 0.2 0.0 Ethyl ene 0.1 1.5 1 .1 0.8 1.4 1.5 1.3 0.0 Aromatics 0.6 0.8 3.4 4.1 2.2 1.5 2.2 3.8 Hydrogen 83.8 79.0 50.6 48.4 42.2 44.4 34.4 59.0 Carbon Monoxide 1.0 2.3 3.9 1.6 0.7 0.4 0.8 1.2 Ethane 0.0 0.0 5.5 0.0 0.0 0.0 0.0 0.9 Methane 9.1 16.6 22.1 41.5 48.9 48.0 58.8 12.8 Nitrogen 3.5 0.0 11.0 3.0 6.4 3.8 2.3 2.1 Total Gas Cu.ft. 5.2 8.0 1.5 3.0 6.8 10.2 10.0 13.4 Percentage Loss 6.0 20.0 12.0 8.0 23.0 25.0 33.0 20.0 Up to 105°C • • • 1.0 1.0 7.0 7.0 8.0 tr 105 to 130°C • « t 18.0 40.0 45.0 56.0 43.0 10.6 130 to 145°C 91.0 66.0 43.0 26.0 5.0 2.0 64.4 Above 145°C 3.0 3.0 8.0 9.0 7.0 14.0 5.0 145 to 170°C 12.8 170 to 225°C 13.3 225 to 325°C 44.4 325 to Coke 20.4 Coke 8.8 37 The results, although differing in many details, show fair agreement with the previous runs. The one striking differ- ence is that the percentage of hydrogen in the issuing gas is approximately one-half as much as previously. In run 59 the hydrogen was admitted slowly from the tank and seems to have materially increased the toluene fraction. This is in direct contradiction to the results obtained by Cobb and Rollings. They found that the presence of hydrogen when passing toluene through red-hot coke, greatly increased the decomposition of toluene to benzene. Of course, there are many other conditions, in the two sets of experiments which are vastly different, and which play an important part. Although, it may be possible that the largest percent of this increase is due to benzene, which was stabilized by the hydrogen. In run 60, the steam superheated to 90Q°C was admitted slowly during the run. The total water condensed amounted to 1020 gms . The stabilizing effect of steam is very noticeable, it seems to have lessened all the various conditions which had been promoting decomposition. 7. SERIES OF RUNS THROUGH IRON FURNACE. At this stage of the investigation, it was decided to examine further the effects of the iron surface of the furnace, on xylene. Up to this point so many contradictory results had been obtained, and so many factors had influenced the reactions, it was necessary to prove definitely what part the iron surfaces . 36 took in the reactions. Accordingly, the furnace was allowed to cool, the cap removed and the charcoal withdrawn. The furnace walls were thoroughly cleaned with a wire brush, the cap replaced and the furnace heated up while superheated steam was passing- through it. The steam was continued for some hours and until the o furnace had reached a temperature of 650 0. 39 TABUS 5. Summary of runs through the furnace without any charcoal. The furnace had been heated to 640°C while superheated steam was passing through. 500 gms. xylene was used in each run, which required one hour. No. of Hun 61 62 63 64 69 70 72 74 Gas introduced St earn • • • *2 « • • • • • H 2 H 2 C0 2 Pressure lbs. Atm . Atm. Atm. Atm. Atm, 35 140 Atm. Temperature d 650 675 650 625 660 650 625 600 Carbon Dioxide 25.1 > 1.2 0.3 6.4 0.3 0.2 0.3 53.8 Oxygen 0.7 1.3 0.2 1.0 0.4 0.2 0.1 0.3 Acetyl ene 0.0 0.3 0.2 0.4 0.7 0.5 0.2 0.1 Ethylene 1.2 1.7 0.2 0.3 0.8 0.2 0.5 0.3 Aroma-tics 2.5 10.0 0.6 0.1 0.2 1.0 0.7 0.3 Hydrogen 56.3. 26.8 74. 7 82.8 82.4 62.9 55.0 20.2 Carbon Monoxide 3.0 1.2 13.9 2.5 5.7 2.9 1.0 19.8 Ethane 1.0 3.8 2.0 0.2 0.0 0.0 0.0 0.0 Methane 6 . 6 50.0 6.3 12.7 9.5 32.0 40.8 5.2 Nitrogen r*-. *• » 3.6 3.7 1.6 0.0 0.0 0.0 1.3 0.0 Total Gas cu.ft. 5.1 1.5 13.6 16.4 17.0 12.0 6.5 26.5 Percentage Loss 12.0 10.0 60.0 100.0 100.0 99.5 99.5 55.0 Up to 105°C • « « 2. 0 tr • • « • • i • • • 105 to 13C°C tr 22.0 12.0 • • • • • • • • • 130 to 145°C 86.0 61.0 25.0 tr tr 44.0 Above 145°C 2.0 5.0 3.0 • • • • • • • 1.0 jJv, 4Q In this series of experiments many interesting details are clearly demonstrated. In run 61 the protecting action of steam is clearly shown, also the percentage of carbon dioxide is slightly greater than in the case where the furnace contained charcoal. In this case the carbon must be coming from the de- composed xylene. In Ho. 62 the steam was discontinued and the run made at once without any change being made in the furnace with the exception of a slight rise in temperature. Here the decomposition of the xylene was greater but the loss was even less, more going to lighter boiling products. Run 63 was made directly after 62 without any change except a lowering of the o temperature 25 C. With this run, hydrogen from a cylinder was introduced in a slow stream intended to maintain reducing condi- tions in the furnace, with hydrogen, other than that from the decomposition of xylene. In former runs, it was found that af- ter the furnace and charcoal had been steamed, and then reduced to a certain degree by hydrogen, that the furnace reached a condition, which for the sake of distinction, we might call "activated”. In this condition the tendency was for complete destruction of the liquid hydrocarbons into hydrogen, carbon and some methane. Run 63 was made in order to see if this activated condition could be obtained without the presence of charcoal. When the run was about three-quarters completed, a great increase in the outcoming gas was noticed and the conden- sate gradually diminished and finally stopped. When this happen- ed, the furnace temperature fell considerably. After waiting during thirty minutes, run 64 was made to see if this "activated" 41 . condition still continued, the results are conclusive. The furnace was new allowed to become cold, out of con- tact with air, and after standing a few days was opened. On removing the deposited carbon, which was intensely black and fluf- fy, it was found to weigh 870 gms . or practically the theoretical amount possible from the 960 gms. of xylene decomposed. On fur- ther analysis, however, the carbon was found to contain approxi- mately 11 % iron, which was found to be a mixture of the magnetic oxide, and other oxides along with some fine particles of reduced iron. The magnetic oxide, seemed to form the largest percentage . After thoroughly cleaning out all carbon by means of a wire brush, the furnace was heated up to 640°C and a series of runs made to see if it was still activated. Run 65 at 635°C was made with xylene alone. The results corresponded very closely with run 62, while runs 66 and 67 at 650 and 675°C were made with hydrogen . The results were similar to run 63. At this stage it was decided to pass super-heated steam through the furnace until fully oxidized or deadened, then reduce some- what with hydrogen from a cylinder and then start another run. Run 68 was made at 665°C and had only been going a few minutes when a sudden increase in the gas given off was noticed and the condensate ceased. Run 69 was made to confirm these results. It was now desirable to see if any of the products of decomposition of the xylene could be stabilized, by means of increasing the hydrogen concentration. Accordingly, in run 70, the furnace was placed under a pressure of 35 pounds per * . , • Hdy. t 'i, $ ■ , . . . • . . 42 . square inch, with hydrogen, before the xylene was admitted. In run 72, the pressure with hydrogen was increased to 140 pounds, before starting, but after the xylene was admitted, the decompo- sition gases were sufficient to keep the pressure at the desired point. These two runs show that it was not possible to stabilize even benzene under these conditions. In the next run at 600°C carbon dioxide was passed through slowly and so changed the con- ditions in the furnace that much of the xylene came through un- changed. The effects of carbon dioxide are somewhat analogous to those of steam under similar conditions. It is possible the carbon dioxide, or more probably the carbon monoxide, formed in both cases, is responsible for this inhibition. This series demonstrates, that the catalyst, whatever it may be, appears to possess the capacity for invigorat ion . It did not prove what this catalyst was, because even minute decompositi on of xylene would deposit carbon, and this carbon may have promoted the de- composition reaction, or again, it may have acted only as a promoter to the iron surfaces. 8. SERIES OF RUNS THROUGH COPPER LINED FURNACE. It was considered more easy to get rid of the influence of iron than of carbon. Accordingly a tube was made from No. 18 sheet copper, which fitted snugly inside the iron furnace and extended under the ends of the caps. In this manner all iron surfaces including the thermo couple pockets, were covered with copper. The influence of copper on the decomposition of xylene is shown in table 6. The copper was oxidized with steam and reduced with hydrogen from the cylinder as in previous runs. t 4 ■ . • ‘ » , ; ■ . . . ' * .. , 1 . . , . > . ■ ■ * TABLE 6 43 . Summary of runs through copper lined furnace 500 gms. of xylene being used per run per hour. Bo. of run 75 76 77 78 79 Gas introduced • • • 9 • • St earn • • H. Pressure lbs. Atm Atm Atm Atm Atm Temperature C 575 625 610 610 610 Carbon Dioxide 2.8 0.7 17.4 3.8 not Oxygen 0.6 0.3 2.0 2.4 run Acetylene 0.3 0.4 0.4 0.4 Ethylene 0.9 1.2 1.6 1.4 Aromatics 0.8 2.4 2.4 5.4 Hydrogen 69.1 76.0 62.8 40.4 Carbon Monoxide 14.5 5.2 4.1 2.6 Ethane 2.7 2.3 0.9 0.0 Methane 4.2 11.1 8.0 31.9 Nitrogen 4.1 0.4 0.4 11.7 Total gas cu.ft. 3. 8 4.7 3.0 0.7 8.5 Percentage Loss 37.5 32.5 12.0 7.5 12.5 Up to 105° C 0.0 0.0 0.0 0.0 0.0 105 to 130°C 3.0 5.0 10.0 25.0 7.5 130 to 145°C 55.5 62.5 75.0 63 . 6 76.5 Above 145 C 4(,0 tr 3.0 4.0 3.5 44 . These results show that somewhat greater decomposition took place in the copper than in the iron furnace. comparing runs 61 and 76, it can he seen that steam exerted similar influ- ences in each case. Run 79 was made after reducing the furnace some time with hydrogen. It was not found possible to activate the copper lining so that complete decomposition took place as happened in the case of iron. After cooling the lurnace v;ab opened and only a gram or so of carbon was found scattered along the bottom. In this case it would appear that the carbon had disappeared in gaseous form rather than being deposited. ihe cooper surface was highly reduced and in a clean condition. 45 TABLE 7. Summary of runs through copper lined furnace containing 2-g- kilos of charcoal cubes, each run consisted of 200 gms. of xylene, a.nd was fed through furnace in one hour. The percentages given for the high boiling (above 145) were obtained from 50 gms. obtained in these runs. No . of Bun 81 82 83 84 85 86 88 Gas introduced • • • • • • • • • • • • St earn H 2 Pressure lbs. Atm Atm Atm Atm Atm Atm Atm Temperature 0. 600 630 680 750 735 750 765 Carbon Dioxide 2.9 1.8 1.0 0.8 20. 7 2.0 0.6 Oxygen 0.5 0.4 0.5 0.5 0.6 1.1 0.4 Acetylene 0.6 0.2 0.5 0.1 0.3 0.6 1.0 Ethylene 2.3 3.5 1.4 1.4 1.4 1.2 2.4 aromatics 0.5 2.5 0.4 0.7 1.0 1.2 1.6 Hydrogen 34.2 18.2 36.3 31.0 43.7 36.5 44.5 Carbon Monoxide 17.9 27.4 10.2 9.6 16.7 11.5 13.8 Ethane 10.8 7.5 0.0 0.0 4.2 2.0 0.8 Methane 20.0 30.4 45.3 57.2 9.3 39.5 35.0 Nitrogen 10.3 3.1 4.4 0.0 0.8 4.4 0.0 Total gas cA-jt. 1.3 1.2 3.3 3.2 15.5 4.5 4.0 Percentage Loss 25.0 17.0 50.0 70.0 55.0 78.0 63.5 Up to 105°C 2.5 2.0 10.0 10.0 5.0 18.0 18.0 105 to 13C°C 25.0 18.0 20.0 15.0 8.0 0.5 12.5 130 to 145 °C 45.0 55.0 15. 0 0.0 26.0 0.0 0.0 .bove 145°C 145 to 170 C 1 70°C to 225°C 225 to 3C0°C 300 to 400 C 400 to Coke Coke 2.5 45.5 4.9 16.5 21.3 5.6 6.2 8.0 5.0 5.0 6.0 3.5 6.0 46 . In this series of runs no exceptional incidents were noticed. Several runs were made between 86 and 88 with and without hydrogen, in an effort to get the furnace in an activated condition "but without success. Run 88, with hydrogen, indicates that here the hydrogen cut down the actual loss "by stabilizing the lower boiling fractions. The next series of runs were made, over oxidized Illium turnings . These turnings had been heated to 800 0 and oxidized by means of oxygen from a cylinder. Three and one-half kilos of oxidized turning were mechanically mixed with small pices of pumice stone and by means of a paper tube were placed inside the furnace. Table 8 summarizes the results. , , . TABLE 8. Summary of runs through copper lined furnace over 3£ kilos of oxidized Illiurn turnings suspended in pumice stone. 200 grns . xylene used per run per hour. High boiling percentages given from 90 gms. obtained in runs. N6. of Run 91 92 93 94 95 96 97 Gas Introduced • • • • • • • • • • • • • « • V H 2 Pressure lbs. Atra Atm Atm Atm Atm 30 Atm Temperature C 525 600 650 700 785 785 785 Carbond Dioxide not 6.8 not 1.7 1.3 0.6 0.3 Oxygen run 1.4 run 0.8 0.6 1.0 0.1 .acetylene 0.8 1.3 0.7 0.8 0.8 Ethylene 4.0 3.0 1.8 1.8 1.8 Aromatics 2.0 2.0 2.0 1.6 1.8 Hydrogen 45.8 33.7 36.2 40.9 50.2 Carbon Monoxide 5.6 14.8 4.2 4.2 11.2 Ethane 1.9 1.5 0.0 0.0 0.0 Methane 25.3 37.4 53.2 49.1 34.2 Nitrogen 6.4 3.8 0.0 0.0 0.0 Total Gas 0.2 0.5 1 .3 2.4 3.5 4.5 8.0 Percentage Loss tr 3 . C 15.0 29.0 76.0 88.5 73.5 Up to 105°C 5.0 4.0 tr 6.0 7.0 8.0 3.0 105 to 130°C 3.0 10.0 12 .0 40.0 7.0 0.0 10.0 130 to 145 °C 84.0 79.0 77.0 17.0 0.0 0.0 6.5 Above 145°C 3.0 4.0 6.0 8.0 10.0 3.5 7.0 145 to 1 70°C 17.7 0 170 to 225 C 11.1 225 to 300°c 16.6 300 to 400° C 22.2 400 to Coke 22.2 Coke 10.2 * ^ — = : — = ffr 5 ! The results with Illiurn oxide, show that in the region of 700°C the decomposition of xylene into the toluene fraction is maximum. Above this temperature the lower boiling fractions decrease with a slight increase in the higher boiling compounds. It is very probable that much more interesting results would have be n obtained by using the Illium turnings without oxidixing. The pieces of pumice when broken up, showed that hydrocarbon vapors had penetrated them throughout. They contained very fine particles of carbon in the centre of even the largest pieces. The next runs were made to find out the effects of finely divided nickel under similar conditions. Accordingly small pieces of pumice, about l/2 inch square, were dipped in heated nickel nitrate. The nitrate was heated in a nickel crucible until most of the water of crystallization was driven off, and the fluid became syrupy. The cubes were then dried at 120°C for a few hours, placed in paper tube and inserted into the copper lined furnace. The temperature was esse raised to 500°C and the nickel reduced with hydrogen from a cylinder. Five pounds of nickel nitrate was used. The results are given in table 9. , . ■ • • ' • • . • . t - . . . 49 TABLE 9 Summary of runs using nickel , which had been reduc ed from the nitrate, per hour. on pumice cubes. 200 gms. xylene used per run No. of Run 100 101 102 103 104 105 106 107 Ga3 Introduced • • • • • • • • • • • • • • • H 2 St earn • • • Pressure lbs. Atm Atm Atm Atm Atm Atm Atm Atm Temperature °C . 500 550 605 665 700 730 735 735 Carbon dioxide 0.8 0.7 0.5 0.7 0.7 0.1 7.0 not Oxygen 0.0 0.3 0.5 0.7 0.7 0.4 0.4 run Acetylene 0.0 1.0 0.6 0.9 0.6 1.1 0.7 Ethyl ene 0.4 1.0 1.7 2.0 2.2 0.7 1.1 Aromatics 0.2 1.2 1.0 1.6 1.2 1.2 1.1 Hydrogen 5 7.3 70.5 63 .8 63.3 53.8 82.0 62 . 3 Carbon Monoxide 10.3 4.6 5.6 3.6 5.0 2.2 15.5 Ethane 0.0 0.0 0.0 0.0 0.0 0.0 2.7 Methane 23 .9 21.2 24.4 28.6 33.6 9.3 5.0 Nitrogen 8.1 0.0 1.9 0.0 2.2 3 .0 4.2 Total Gas Cu.Pt. 3.2 3.6 2.5 3.0 3.7 15.0 13.2 8.0 Percentage Loss 64.0 63.5 42.0 49.0 64 .0 97.5 71.0 98.0 Up to 105°C • • • • • • • • • 2.5 2.5 2.5 • • • • • • 105 to 130°C tr . tr . 3.5 15.5 19.0 10.0 tr 130 to 145°C 33.0 33 . 5 50.5 29.0 9.5 17.5 tr A.bove 145°C 3.0 3.0 4. 0 4.0 5.0 1.5 • • • 50 . It is quite apparent that nickel, under these conditions did not promote the formation of high boiling compounds but seemingly promoted complete destruction of the condensable hydro carbons. In each of these runs considerable moisture was col- lected. Only small traces of unoxidized nickel was to be found on the pumice. The pumice resembled chunks of coke embeded in lamp black. The burning gas gave a distinct nickel flame. At the conclusion of this series of experiments the copper lining was found to be in a poor state of repair. In the hotter part of the furnace it had crystallized and fallen to pieces leaving considerable surface of the iron furnace again exposed to the reactions. Hear the ends some areas of it was found to be highly reduced while mixed with these were spots covered with a thick layer of oxide. It is quite certain that in the last of the previous series of runs, the iron surfaces were playing a part. The copper lining was removed and replaced by one of tinned-copper, the tinned surface being on the inside. This tube was lap-welded and riveted and made to fit snugly into the furnace, covering all iron surfaces. 9. SERIES OF RUNS USING TINNED-COPPER LINING IN FURNACE. In the preliminary runs on this lining the temperature was not raised much above 605°C, in order to prevent scaling off the tinned surface. The results are given in Table 10. 51 TABLE 10. Summary of runs using tinned-copper lining in furnace. 2C0 gms. of xylene used per run per hour. No. of Run 110 111 112 113 Gas Introduced • • • • • • • • • • • • Pressure lbs. At m Atm At m Atm Temperature C. 425 50 0 550 625 Carbon dioxide Not 2.0 1.3 1.0 Oxygen 0.7 1.1 0.9 Acetylene run 0.2 0.4 1.0 Ethylene 1.7 2.1 9.2 Aromatics 1.0 5.3 2.7 Hydrogen 71.4 53.0 29.4 Carbon Monoxide 6.5 5.0 3.6 Ethane 0.0 0.0 0.0 Methane 12.9 31.4 58.0 Nitrogen 3.5 0.4 1.2 Total gas cu.ft. 0.2 0.6 1.0 1.5 Percentage Loss 12.0 8.0 14.0 2 7.0 Up to 105°C « • • 2.5 2.0 5.0 105 to 130°C • « • tr 12.0 25.0 1.30 to 145 °C 84.5 86.5 69.5 36.0 Above 145 °q 3.5 3.0 2.5 7.0 52 . These results indicate that in the neighborhood of 700°C a tinned surface in the furnace would be favorable for the production of toluene and benzene from xylene. The next series of runs were 'aade to find out the effects on xylene, of finely divided nickel-oxide on charcoal under various conditions. The 2-g- kilos of charcoal cubes, which had been used previously in the copper lined furnace, were heated at 700°C in an atmosphere of hydrogen, allowed to cool, - out of contact with air, - then dipped in a thin paste containing one pound of nickel oxide. After being dried at 110°C they were placed in a paper tube and insetted in the furnace, in the usual manner. In this series the nickel oxide was not reduced with hydrogen before the runs were started. The results are tabulated in Table 11 53 table 11 . Summary of runs over nickel oxide on charcoal. 200 gins. of xylene used ; per run per hour. Tinned copper lining 1 in furnac No. of run 120 121 122 123 124 125 126. Gas introduced • • • • • « • • • • • • • • • H 2 Air Pressure lbs. Atm Atm Atm Atm Atm 15 Atm. Temperature C- 475 525 565 600 650 665 665 Carbon Dioxide 1.0 0.0 1.0 0.8 0.5 0.0 0.4 Oxygen 1.0 0.4 0.8 0.9 0.3 0.0 0.5 Acetylene 0.1 0.4 0.0 0.1 0.* 0.0 0.0 Ethylene 0.3 0.5 1.0 1.0 0.5 0.4 0.9 Aromatics 0.3 0.3 0.6 0.7 0.5 0.6 0.5 Hydrogen 64.0 65.4 67.6 66 . 8 80.0 81.5 77.3 Carbon Monoxide 8.5 5.9 6.4 8.0 5.8 3.4 5.3 Ethane 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Methane 24.8 23.6 18.8 19.4 11.8 14 .1 15.1 Nitrogen 0.0 3.4 3.8 2.3 0.0 0.0 0.0 Total Gas cu.ft 3.2 3.9 4.0 4.5 7.0 9.0 6.0 Percentage Loss 82.5 77.5 63.5 33.0 98.0 100.0 96.0 Up to 105°C 0.0 4.0 tr tr • • • • • • tr 105 to 130°C tr tr 6. 0 9.0 • • * . . . tr 130 to 145°C 14.5 13.5 25.0 3.0 2.0 • • • tr Above 145°c 3.0 5.0 5.5 5.0 • • • • • • 54 In each of the above runs three to five grans of water were collected. The combination of hickel oxide and charcoal gave results similar to the iron oxides and charcoal. Before run 125 the outfit had been reduced for one hour with hydro- gen under 15 pounds pressure. Before run 126 nine cubic feet of air had been passed through the hot furnace but was dicontinued during run. When the furnace was cleaned after this series, it was found that practically all the tin surface had scaled off the copper tube. Thus copper as well as tin could have exerted an influence on the last runs. ■ - 55 TABLE 12. Summary of runs through copper lined furnace over l/2 pound of molybdenum powder, mixed dry among small pieces of pumice stone. 200 gms. of xylene used per run per hour No. of run 130 131 132 133 134 Gas Introduced • • • • • • • • • • • • H 2 Pressure lbs. Atm Atm Atm Atm 60 Temperature f C 550 600 650 680 690 Carbon Dioxide 0.9 0.6 0.4 0.6 0.6 Oxygen 1.0 1.0 0.4 0.0 0.7 Acetylene 0.5 0.3 0.5 0.3 0.4 Ethylene 1.8 0.9 1.1 1.1 0.6 Aromatics 5.5 2.8 0.3 1.6 1.1 Hydrogen 5 7.9 46 .0 30.9 33.4 36.4 Carbon Monoxide 4.2 10.8 3.4 2.2 2.4 Ethane 0.0 0.0 0.0 0.0 0.0 Methane 22.5 38.5 59.9 60.8 54.6 Nitrogen 5.9 0.0 3.1 0.0 3.2 Total gas cu.ft. 0.7 1.8 3.0 3.3 8.0 Percentage Loss 30.0 30.0 65.0 76.5 81.0 Up to 105°C 0.0 lost 15.0 16.5 11.0 105 to 130°C 5.0 II 13.0 0.0 0.0 130 to 145°C 63.0 II 0.0 0.0 0.0 Above 145°C 2. 0 3.0 7.0 7.0 8.0 ■U 56 This series of runs was made with the temperature of the furnace gradually increasing. In each run four to six grams of water were collected. Molybdenum promotes the decomposition of xylene to methane rather than to hydrogen. If the conditions were favorable it should be a good contact surface for the production of benzene. After completing the runs over molybdenum the furnace was cofcled, under an atmosphere of hydrogen, and the carbon depo- sition removed. ^t this time some places in the copper lining had given away thus exposing a few small patches of iron surface. The following runs were made over metallic cobalt cubes. Three kilos 2 cm. square and 3 kilos 1 cm. square, were placed in a paper tube and inserted into the furnace in the usual manner. The temperature was raised to 470°C and the whole outfit kept under a pressure of 60 pounds of hydrogen for two hours before commencing the runs. Even after this treatment moisture was collected in each run, due, presunably, to the reduction of oxi des. The results are given in Table 13. ► - * *> «? $ Table 13 Summary of runs over metallic cobalt cubes. 200 gms. xylene used per run per hour. Ho. of run 140 141 142 143 144 145 Gas introduced • • * • • • « • • • • • • • • H 2 Pressure lbs. Atm Atm Atm Atm Atm 110 Temperature °G. 475 525 575 625 660 660 Carbon dioxide 0.9 0.7 0.6 0.4 0.5 0.7 Oxygen 0.7 0.1 0.6 1.5 0.6 0.9 Acetylene 0.3 0.6 0.2 0.5 0.4 0 . 4 Ethylene 1.2 2.4 1.5 1.2 1.4 0.9 Aromatics 0.8 1.2 1.4 1.3 1.3 1.4 Hydrogen 80.2 76.7 76.7 72.8 69.1 32.3 Carbon Monoxide 3.8 4.0 4.6 1.3 0.7 0.4 Ethane 0.0 0.0 0.0 0.0 0.0 0.0 -w-e thane 11.0 12.9 12.6 21.7 26.0 61.4 Nitrogen 1.1 1.4 1.8 0.0 0.0 1.6 Total gas cu.ft. 1.4 2.3 3.2 4.6 5.4 5.1 Percentage loss 35.0 38.0 45.0 73.0 96.5 90.0 Up to 105°C 1.0 tr 2.0 7.5 1.5 8.5 105 to 130°C 4.0 8.0 29.0 12.5 0.0 0.0 130 to 145°C 55.0 50.0 20.5 4.0 0.0 0.0 Above 145°C 5.0 4.0 3.5 3.0 2.0 1.5 The general reactions of cobalt can be seen from the table, however, the influence of some iron surface, although not activated ought not to be underestimated. The tendency t 58 destroy the hydrocarbon rather than to build it up boiling compounds is evident. Around 575°C cobalt favor the formation of toluene. into higher appears to Table 14 59. Summary of runs, through copper lined furnace over two pounds of finely divided manganese, scattered through small pieces of pumice stone. 2 00 gms . o f xylene used per : No. of Run 150 151 152 153 154 (las introduced • • • • • • • • • • • • h 2 Pressure lbs. Atm Atm Atm Atm 80 Temperature °G, 565 600 645 685 685 Carbon Dioxide 0.3 0.3 0.5 0.4 0.5 Oxygen 0.4 0.5 0 . 6 0.2 0.5 Acetylene 0.5 0.5 0.5 0.5 0.4 Ethylene 2.6 3.4 3.1 1.1 1.0 Aromatics 2.1 1.3 0.8 1.7 1.4 Hydrogen 53. 4 52.2 42.6 48.8 52.6 Carbon Monoxide 2.9 0.4 0.9 1.2 1.3 Ethane 0.0 0.0 0.0 0.0 0.0 -“•ethane 32.3 40.4 51.0 46.1 39.6 Nitr ogen 5.5 1.0 0.0 0.0 2.6 Total gas cu.ft. 1.2 2.1 2.7 4.2 6. 0 Percentage Loss 30.0 44. 0 50.0 84.0 97.0 Up to 105°C 2.0 4.0 11.0 11.0 3.0 105 to 13Q°C 24.0 30.0 27.0 0.0 • • • 130 to 145 °C 36.0 6.0 0.0 0.0 • • • Above 145°C 8.0 16.0 12. 0 5.0 • • • This series would indicate that the presence of mangan- ese influences the partial decomposition of xylene at lower 60 temperatures than the previous metals. In the neighborhood of 600 °C the high boiling, as well as the low boiling, products are maximum; also the ethylene content of the escaping gas is highest. Again, the influence of the snail, exposed, iron sur- faces of the furnace and also the copper lining must be taken into c onsiderati on . Some traces of water were noticeable in these runs. . L ■ , ■' : ■ ;fr ' .• . ■ ■ ■ • ' f : j 0 :j|« ' ' " > TABLE 15 Sumaiary of runs made through copper lined furnace, over 440 gins, of aluminum powder scattered through small pieces of pumice. 200 gins, of xylene used per run per hour. No. of Run 160 161 162 163 165 Gas introduced • • • • ♦ • • • • • • • H 2 Pressure lbs. Atm Atm Atm Atm 70 Temperature °C. 525 550 600 680 700 Carbon Dioxide 0.2 0.4 0.6 0.4 0.4 Oxygen 0.1 0.3 0.9 0.7 0.4 Acetylene 0.3 0.3 0.5 0.3 0.2 Ethylene 2. 0 2.7 2.0 1.5 1.1 aromatics 1.8 1.6 1.3 1.0 1.1 Hydrogen 74.0 73.4 76.7 72.5 80.5 Carbon Monoxide 1.6 1.5 0.8 1.0 0.8 Ethane 1.7 0.5 0.0 0.0 0.0 Methane 12.5 16.3 17 .2 22.6 15.5 Nitrogen 6.2 3.0 0.0 0.0 0.0 Total gas cu.ft. 0.9 1.5 4.3 5.0 0.4 Percentage Loss 15.0 25.0 65.0 90.0 96.0 Up to 105°C 1.0 0.0 0.0 0.0 4. 0 105 to 130°C 8.0 4.0 10.0 8.0 • « • 130 to 1 45°C 70. 0 67.0 22.0 0.0 • 4 • Above 145°c 6. 0 4.0 3.0 2.0 • • • Some water was collect' ed in all these run exception of number 163 and 165. When cleaning the furnace •v • ■v t 62. after completing this series the copper lining w as found to be broken in so many places, exposing the iron surface, that it was decided to remove it. 10. SERIES OF RUMS USING REFRACTORY LINING IN FURNACE. The furnace was cleaned by means of a wire brush, heated to 600°C and kept under 100 pounds pressure with hydrogen, for some hours, to reduce any adhering oxide. It was then cooled, under an atmosphere of hydrogen, again cleaned with the wire brush, and then coated by means of a brush, with a thin paste made by mixing 80 per cent of Hytempite with 20 percent Alundum cement. This coating was allowed to air dry before a second coating was put on. The furnace was then heated to 500°C and some runs made to find out the effects on xylene under non-metal- lic conditions. The results are given in table 16. „ ■ . • . , < ' . 4 ' • . • ' 63 Table 16. Summary of runs using refractory lined furnace. 200 gms. xylene used per run per hour. No . of Run 166 167 168 Gas Introduced • « « • • • • • • Pressure lbs. Atm Atm Atm Temperature C. 500 550 600 Carbon Dioxide 1 . 5 0.6 1.0 Oxygen 6.1 5.3 0.4 Acetylene 0.5 0.7 0.6 Ethylene 2.8 4.2 4.4 Aromatics 1.8 4.1 1.8 Hydrogen 55. 4 22.1 25. 6 Carbon Monoxide 0.6 0.3 2.4 Ethane 0.0 0.0 9.0 m ethane 13.0 25.8 42.6 Nitrogen 18.3 36.9 12.2 Total gas cu.ft. 0.2 0.4 1.0 Percentage Loss 25. C 14.0 25. 0 Up to 105°C 1.0 1.0 Lost 105 to 130°C 5.0 9.0 II 130 to 145°C 66.0 71.0 II Above 145 C 3.0 5.0 12.0 After completing this series the furnace was cooled and opened. In a few places small patches of refractory had fallen 64 . off the furnace wall. Directly under these places were found small mounds of carbon , apparently due to the decomposition of xylene by the exposed iron surface. The furnace was cleaned of all deposited carbon and again coated with the refractory paste. This was to make certain that all iron surfaces were covered before commencing a new series of runs. A cylinder of ethylene, put on the market by The United States Industrial Chemical ^o., Curtis Bay .Baltimore , under the trade name of ’'Calorene" had been secured to use in these runs. In previous experiments it had been noticed, that when the outgoing gas contained any appreciable amount of ethylene, the condensate contained larger amounts of the higher boiling products. In this series the aim was to obtain the maximum percentage of these high boiling compounds. Also to determine, if possible, if by definite control of the atmosphere within the furnace, the desired end products could be obtained. In other words, it was decided that certain definite conditions in regard to temperature and contact surfaces were necessary to practically deco.npose the xylene molecule, regardless of the end products obtained and, that the reaction could be driven, by mass action, to yield the products desired. That is, if the furnace was in a proper condition to decompose xylene freely, but not too streneously, that by keeping the atmosphere in the furnace mostly hydrogen, benzene could be obtained as an end product; while if the atmosphere in the furnace was mostly ethylene, the end products would likely be higher boiling confounds The results are shown in Table 17 . . . * ■ . . 1 . . . ■ ; . ; • 4 ■ . • c- , < t P H * l \ .. . • • '• ; . ,,, 65 Table 17. Summary of runs through refractory-lined furnace, without any other contact surface, using calorene or hydrogen. 200 grns. xylene used per run per hour. No. of Run 183 184 185 186 187 188 189 190 Gas Introduced c 2 h 4 C 2 H 4 c 2 h 4 c 2 h 4 H 2 h 2 C 2 H 4 c 2 h 4 Pressure lbs. 45 45 45 Atra 150 125 45 90 Temperature C. 500 550 6 00 610 615 650 670 710 Carbon Dioxide 0.0 0.6 0.4 0.4 0.0 0.5 0.3 0.0 Oxygen 0.0 0.4 0.5 0.3 0.1 0.2 0.4 0.0 Acetylene ■ 0*1 0*4 1*0 0.7 0.2 0.3 0.9 0.0 Ethylene 53.4 9.0 3.5 31.1 0.4 0.5 2.6 1.5 Aromati C3 0.7 1.3 1.9 0.6 0.4 0.6 1.3 1.2 'Hydrogen 2.0 8.6 6.7 4. 0 60.0 58. 7 6.0 28.8 Carbon Monoxide 3.5 4.9 3.3 3.1 4.0 5.2 4.4 6 .8 Ethane 12.7 7.4 8.6 22.8 0.0 0.0 0.0 0.0 Methane 23.0 67.4 73.3 37.0 34.9 35.7 84.1 62.3 Nitrogen 0.0 0.0 0.7 0.0 0.0 0.0 0.0 0.0 Total gas cu.ft • 1.3 0.8 0.5 10.0 6.5 7.4 0.4 4.3 Percentage Loss +1.0 22.0 34.0 2 7vU~‘ 26.0 37.5 75.0 67.5 Up to 105°C tr . 7.5 18.5 tr 69.0 55.5 10. 0 17.0 105 to 130°C 3.0 24.0 4.0 0.0 0.0 0.0 0.0 0.0 130 to 145°C 79.0 16.5 0.0 0.0 0.0 0.0 0.0 0.0 Above 145°C 18.0 30.0 43.5 77.7 5.0 7.0 15.0 15.5 The fir st runs of this series were made at 350,400 ,415, 450 and 475°C. They were all . made under a pres sure of 45 pounds * V < f < t 66 built up by ethylene from the cylinder. At these temperatures there was very little decomposition of xylene, ranging from two to eight percent, the majority going into higher boiling compounds. In each of these runs, however, there was a gain in weight, from one-half to one and one-half per cent of the original xylene. This was found to be due to dissolved ethylene, which was driven off again when fractionating the condensate. Another significant result shown by the gas analysis was the stability of ethylene o under these conditions. At 415 C the waste gas contained 89.4 percent ethylene, no ethane and 8.5 percent methane; while at 475°C it contained 73.9 percent ethylene, 4.6 percent ethane o _ and 8.0 percent methane. At 500 C the maximum percentage of ethane was obtained while the percentage of methane increased with temperature. In all the runs with ethylene, it was necessary to conserve the gas as much as possible, so that, when running under 45 pounds pressure, the waste gas was allowed to escape slowly, otherwise no ethylene could be added because the decomposition gas kept the pressure increasing. Run 184 indicated that the conditions, where all the xylenes were being decomposed were being approached. Run 185 showed the optimum temperature was in that neighborhood, also that the conditions were favorable for the formation of high boiling compounds. At this tempera- ture ethylene was found to decompose rapidly the majority going to methane. ITow for the building up of high boiling compounds the larger the excess of ethylene in the furnace the better, 6? therefore in run 186, the pressure was reduced to 4 or 5 pounds, and the ethylene passed into the furnace in a very rapid stream. In this manner the products were driven through the furnace faster than usual, without allowing the decomposition of the products, or more especially of the ethylene, to become complete. This run gave the maximum yield of high boiling compounds . At this point it was desirable to find out if these particular conditions were favorable for forming lower boiling hydrocarbons and if they could be stabilized and recover- ed. Hun 187 gave conclusive evidence that this was possible. It is interesting to analyze these results a little farther. The yield of 69.0 percent is calculated from the weight percent of the original xylene used. By referring to the equation, CgHj 0 + 3 *==* 3 CH 4+ OqHq we see that 69.0 percent by weight equals 93.8 percent of the possible theoretical yield of benzene. The remainder of these runs demonstrate that the optimum temperature for the desired results is in the neighbor- hood of 600°C. At the higher temperatures the water collected appeared to increase slightly. When the furnace was opened, after cooling, the >whdLe interior was coated with a fluffy layer of carbon, which was very different in appearance from previous deposits. It was a metallic gray color and granular or sandy, while the other deposits had been intensely black and amorphous. It was evenly distributed along the walls of the furnace, even where no iron was exposed. In previous cases the deposits were directly , ' • • ' ■ ■ : “ .... ■ • ■ . -cr . y. . J •- • ; j.i X. • 1 ■ '• ■ * - . r • \ ’ r . . \ ■ . , j. ' i . . 68 opposite the exposed iron surfaces. It does not seem possible, that the very small amount of iron exposed could have been re- sponsible for all the carbon deposited, however, it may have started the reactions which were carried along by the carbon thus deposited. The next series of runs, after cleaning the furnace entirely free from carbon, were made with some small patches of iron exposed. This was calculated to promote the decomposi- tion of xylene at lowered temperatures and thus allow a better yield of high boiling compounds. Table 18 shows that this was only partially successful. ■ . * . • :v >1 ■ 69 Table 18. Summary of runs through refractory lined furnace with some iron surface exposed. 200 gras, of xylene used per run, the time of feed varied from 5 minutes to four hours. No. of Run 200 203 205 207 208 210 St earn 211 212 Gas Introduced C 2 H 4 C 2 H 4 C 2 H 4 c 2 h 4 St earn C 2 H 4 C 2 H 4 c 2 h Pressure lbs. 45 125 140 60 Atm Atm 145 75 Tenperature °G. 525 490 580 620 615 585 525 460 Carbon Dioxide 1.1 0.4 0.0 0.0 0.6 1.4 0.6 not Oxygen 0.2 1.8 0.3 0.2 0.5 0.5 1.7 run Acetylene 0.5 0.7 0.3 0.3 0.5 0.5 0.5 Ethylene 21.8 25.1 5.1 1.6 6.2 33.0 13.0 Aromatics 1.0 ' 0.6 0.8 0.3 0.5 0.6 0.0 Hydrogen 13. 4 7.2 6.6 39.5 43.3 30.9 2.0 Carbon Monoxide 4.2 3.1 2.3 2.6 1.6 1.1 4.5 Ethane 30.9 21 .9 8.3 8.0 0.0 0.0 15.1 Methane 26.9 33.0 75.3 47.5 45. S 32. 0 60.4 Nitrogen 0.0 6.2 1.0 0.0 0.2 0.0 2.2 Total Gas cu.ft. 2.5 2.4 5.2 14.6 2.4 3.1 12.2 12.5 Percentage Loss 20.0 9.0 25.0 87.5 24.0 30.0 75.0 27.5 Up to 105°C 1.5 1.0 6.0 12.5 tr tr Lbs t 20.0 105 to 130°C 10.0 10.0 20.0 • • • • 25.0 20.0 »» 4.0 130 to 145°C 53.5 22.0 14.0 • i • • 44.0 40.0 H 41.0 Above 145 C 15.0 58.0 35.0 tr . 7.0 10.0 7.5 7.5 These runs were made under what might be termed extreme conditions, to find out if any favorable condition such as pressur? duration of time of contact and mass-action equilibrium had been neglected in previous runs. j ?o. Run 300 was fed at the rate of one drop per second. This was to allow ample time for equilibrium to be obtained among the gases in the furnace. The decomposition was not excessive but the most interesting feature brought out is the percentages of ethylene, hydrogen, ethane and methane in the issuing gases. In run 301 the 300 gms. of xylene was fed in ten minutes. Here the recovered products were of equal weight to the xylene used. The ethylene was fed in an atmospheric pressure and quite rapid- ly. Only 40 percent of the xylene used was changed, it going almost equally into high and low boiling compounds. In run 303 the xylene was fed intermittently, while the ethylene was fed continuously at atmospheric pressure. A marked increased in the high boiling constituents was noticeable. In run 303 the feed interval was about thirty minutes. This contact period seemed favorable for building up the high compounds. In run 311 the rate of feed was 80 drops of xylene per minute: while in all the other runs the former feed rate of 300 grams per hour was used. In runs 306 and 307 the furnace became acti- vated in such a manner, that regardless of how fast or under what pressure ethylene was added, all the hydrocarbons were decomposed to gas and deposited carbon. In fact, it was very similar to the previous mentioned activated conditions. The introduction of superheated steam caused similar effects as previously. The experiments with xylene were discontinued after run 313. When the furnace was opened the deposited carbon had a very peculiar formation. It was suspended from the top of the furnace in -leag fibres from one to two inches long. • - . ■ . 5 ; • ” t ,, < . . ; . A . ; . - . 71 . They might be said to resemble in shape, delicate stalactites. The large increase in the yield of the high boiling hydro- carbons, obtained in the last two series of runs, made it seem profitable to fractionate them further. The results are given in Table 19. . ' . t . . I • . 72 Table 19. Fract ionation of high boiling products obtained from the decomposi tion of xylene. The precentages given in (A) were obtained on 16b grams of high boiling product obtained in the series of runs tabulated in table 17. The results given in (b) are from 325° of high boiling product obtained from the series last tabulated . Boiling range A B Sp.Gr. .15. 5° 0. Remarks 145 to 175°C. 11.5 6.6 0.8911 Light greenish oil 175 to 200°C. • « • • 8.9 0.9057 Light oil, at zero-solid 200 to 225°C. 23.1 4.8 O>.9605 Darker oil, at zero-solid 225 to 240°C. 5 .8 7.2 0.9888 ii it n n it 240 to 255°C. 12.7 8.3 1.0087 High oil with white " 255 to 300°C, 8.0 15.1 1.0232 Oil - shade darker 300 to 350°C. 19.3 23.4 1.0625 ii n ii 350 to 400°C 0 8.0 14.5 1.1032 Reddish oil with yellow solid 400 to 500 C. 7.0 7 .1 Solid " yellow solid 500 to coke 4.5 4.0 It Td-h Crude oil. 1.0808 These results show, that in the last series where greater pressures were used, the higher boilign products contained a larger percentage of solids. In each of these series the final residue or coke amounted to about 4 % of the high boiling product. 73 11. SERIES OP RUNS USING BENZENE. The runs on benzene were made through the iron furnace containing 2-g- kilos of charcoal. The purpose being to try to check Cobb and Hollings ' results. They found that benzene, while passing through coke heated to 800°C could be entirely stabilized by means of excess hydrogen. In these experiments it was found that when the charcoal and furnace was activated, that it was impossible to stabilize the benzene even at 500°C. Pressures as high as 125 pounds of hydrogen per square inch were used. On the other hand, if the charcoal and furnace had been treated with superheat ed- steam, air or carbon dioxide, that the benzene could be entirely stabilized at temperatures as high as 800°C with a very small pressure of hydrogen. The condensation products, other than recovered benzene were not analysed. 12. SERIES OP RUNS USING TOLUENE. Cobb and Hollings had found, that when toluene was passed through red hot coke, that it was nore stable alone than when in the presence of hydrogen. That is, hydrogen caused the decompo- sition of toluene to benzene and methane. In run 58, Table 4, hydrogen was found to increase slightly the toluene fracti on .Pur e toluene was run under similar conditions and it was found that toluene was somewhat more stable in the presence of hydrogen. In cases where the furnace was activated the toluene was entirely destroyed with or without hydrogen. . • ■ • Jr*-* r \ 74 15. SERIES OF RUNS USING NAPHTHALENE. In making the runs on napthalene, it was preheated in an electrical retort, connected to the top< end of the furnace and the vapors carried into the furnace by means of the gasses bubbled through. The products obtained have not all been identified but the analysis of escaping gas is interesting. 75 Table 20. Summary of runs over 2-g- kilos of charcoal in iron furnace, with preheated napthalene, carried into the furnace by means of gases. 300 gins, of napthalene used per run, at atmospheric pre- ssure . No. of Run 220 221 222 223 224 225 Carri er gas . C °2 CO CO H 2 N 2 CO t Pre-heat T emperature°C - 340 320 340 330 330 325 Furnace Temperature°C. 780 525 635 660 640 815 Gas used cu.ft. 2.6 2.4 3.5 3.2 1.4 2.0 Gas recovered cu.ft. 2.6 0.4 2.6 1.4 0.9 1.7 Percentage loss + 0.5 67,5 22.0 28.0 33.3 65.0 Carbon dioxide 36.0 17.7 34.8 2.9 1.2 2.8 Oxygen 4.4 5.2 2.0 2.6 0.8 1.6 Acetylene 0.2 0.3 0.5 0.4 0.1 0.3 Ethyl ene 0.0 0.0 0.3 1.0 0.2 0.4 Aromatics 0.1 0.0 0.3 0 .0 0.1 0.4 Hydrogen 34.8 38.2 21.6 85 .1 6.1 72.0 Carbon monoxide 14.8 17.3 35.6 1.4 2.2 22.5 Ethane 3.0 2. 8 I . 8 0.4 0.2 0.0 Methane 5.5 0.2 0.2 0.6 0.3 tr Nitrogen. 2.2 18.3 2.6 5.6 88.8 0.0 In the runs on naphthalene it was noticed that practical ly as soon as the run commenced the temperature of the furnace dropped. Even when the current passing through the heating elements, was materially increased, the temperature fell slowly. 76 This would indicate the reactions taking place inside the furnace was absorbing considerable heat. Another feature, part i cularly noticeable in the nitrogen run, was that the gas recovered did not equal the amount passed into the furnace from the cylinder , even with the addition of the gas from decomposition of the napthalene. The charcoal may be partly responsible for this result. In the runs using carbon dioxide as the carrying gas, the product contained a heavy, black, high boiling oil, some free carbon, and a very light, fluffy, red material with very little odor of napthalene. With hydrogen thfe product was dark gray con- taining also traces of the light reddish material. The product from the nitrogen rims was a compact greenish color and from carbon monoxide the reddish fluffy material formed the bulk of the recovery. III. SOME PRODUCTS SYNTHESISED IN THE INVESTIGATION. A few of the products, obtained in this investigation, require rather streneous mental gymnastics to explain their forma- tion. Prom the kinetic theory, the intermolecular collisions, which increase with rise in temperature, would account for the rupture of bonds or forces which hold together atoms or groups. Also under like conditions the larger molecules, - higher boiling compounds, - would have a greater momentum than the smaller ones, and on this account at the instant of impact, would be subjected to greater strain. That is, at higher temperatures, benzene should be no re stable than toluene cr xylene; or to obtain toluene from xylene lower temperatures would be more favorable. , • . ' ; < . ( , ■ . . ' . ■ > ; • 77 The process of decomposition of hydrocarbons can never be regarded as a simple effect of heat independent of the gaseous atmosphere in which it is conducted and the way in which we hope to modify the results of decomposition in various directions is by the deliberate control of that atmosphere. The gaseous products obtained in these experiments are extremely important and play as important a part in the final products as the gas introduced. Their effects can be considered from two standpoints .mechanical and chemical. An inert-gas, like nitrogen, would not enter directly into chemical reaction under these conditions, but would play a very important part by washing the products of decomposition from the surface of the contact mat erial , assist their volotilization by lowering their concentration in the vapor phase, and hurry them away from the region of decomposition. In the case of hydrogen, being much lighter, it has a greater diffusing power, the mole- cules travel at a higher speed and thus penetrate small areas where the larger gas molecules never reach. The all-important action of hydrogen, however, is chemical . It tends to reduce the single ring benzene compounds to benzene itself. A similar action may be inferred, as is very probable, on the attached groups of more complicated ring compounds, resulting in the formation of napthalene and anthracene. It seems that this was the part played by hydrogen in the majority of the experiments carried out. However, other factors must be able to modify this tendency of hydrogen because in the experiments giving the largest yields of the toluene fraction, it was found possible to increase this fraction by introducing hydrogen from a cylinder, although it was not definitely proven that this increase was not •> .. , ( • . • , , ■ » . . . . , ' ■ .. • ■ - V ' T • ■ • 7a due to benzene. It was possible to change the production of hydrogen in these experiments by changing the temperature, or the activity of the furnace. Methane could also be produced in varying quantities, de- 24 pending upon the furnace conditions. Bone and Coward concluded that methane decomposes chiefly, directly into hydrogen and car- bon, the process being reversible and a surface phenomenon at least up to 1200°C. At the temperature these experiments were run, methane is practically stable and its chemical reaction would be negligible but its mechanical action would be very important as in the case of nitrogen. The carbon dioxide formed was in small quantities and was always in equilibrium with carbon nonoxide. They seemed to deaden orpoison the activity of the f or nace, although it is pos- sible they caused partial combustion. Acetylene was formed in small quantities and although many investigators claim that the building up process is through the ability of acetylene to polymerize, it was concluded from these experiments, that acetylene played a very small part. At higher temperatures, it was more liable to be decomposed to carbon and hydrogen than to be built up. Thepr oduct ion of ethylene in these experiments was very desirable, because, it was noticed that wherever the percentage of ethylene in the outgoing gas, was around three or four percent, the yields of the higher boiling compounds were appreciably in- creased. In general, it was found, that ethylene decomposed . . . . ■*’ ' . ■ . < , . . * ' , - • 1 • 79 into a mixture of ethane and methane in the neighborhood of 500°C. Above 500°C the ethane content gradually decreased and around 650°C disappeared entirely with a resultant increase in methane. Ethylene seems to be able to decompose in several ways, which no doubt explains its usefulness in the building up process. Bone and Coward concluded that the primary action of heat on ethylene is to eliminate hydrogen. The residue : CH thus formed may decompose or be hydrogenated to methane, or it may unite< with another such residue to form acetylene. Rollings & Cobb found that at lower temperatures, around 800°C it decomposed into methane and acetylene, while at higher temperatures it went into methane and hydrogen. In some of these experiments as high as 15$ of the waste gas was found to be ethane. It was also found that very little ethane was formed below 600°C and that it w as all practically de- composed at 700 to 725°C , except in the presence of steam, which seemed to stabilize it at slightly higher temperatures. These temperatures are far lower than found by Rollings and Cobb who found that the decomposition of ethane was rapid, but not complete in 46 seconds at 800°C . At 1100°C only 88 percent was decomposed, the chief products being ethylene and methane. Ho doubt the mole- cular decomposition of ethane played an important part in these 25 experiments. According to J.J. Thomson , such residues as i CH : CHg and . CHg may exist momentarily in the free state. The four possibilities open to the residue : CHg are: (l) to form ethylene by contact with another similar residue; (2) to break down into carbon and hydrogen; (3) to be hydrogenated to methane; ■ h ' . ♦ ' ' . ' . . ‘ . . * * . >' ■ . ■ 80 . (4) or attach to some heavier molecular formation, - a partial de- composition, of the benzene necleus or homologues. The above is only a partial list of the gaseous consti- tuents in the furnace atmosphere during decomposition, undoubtedly many more complex groups or radicles from the higher boiling compounds exerted an important influence on the process. A few of the liquid hydrocarbons obtained in this investi- gation are listed below. All were definitely identified by the com men tests and known derivatives were made. These results are qualitative only, as no definite scheme of separation has been worked out, Mr. Malecki is working on the solid and liquid pro- ducts obtained in this investigat ion , and his methods of separ- ation, purification and irienti fication will be given in his graduation thesis in February 1922. N-Hexane (B.P.68) wa.s obtained in very small quantities along with another highly unsaturated hydrocarbon, whi ch boiled around the same temperature , in the runs made under high pressure with ethylene . Cyclo hexane (B.P.80) was also obtained in very small quantities in the same runs. Benzene (B.P.80. 5) was recovered and purified from several runs. The largest yield of the crude product obtained was approxi- mately 93.0 percent of the possible theoretical. Toluene (B.P. 110 ) was obtained in many of the runs over char- coal. the maximum yield of the crude product being about 66.0 per- cent theoretical. Very little work has been done on the higher . ' ■ . ( . ■ • - . • • •'-r- * 81 . boiling compounds listed in table 19, Only three having been definitely identified. Pitolyls (mixed, 3.P. about 275C) were identified. A-Methylnaphthalene (B .P.240-242 ) has also been purified; while diphenyl ethane (B. P.286) has been obtained in small amounts. The solids synthesised in this investigation are also ex- remely complex. In a single series of runs the high boiling con- stituents were very similar hn each run, but in different series the variation was marked. It was quite noticeable that when using cobalt and manganese, the high boiling oils had a larger percent- age of solids containing anthracene. Only a very few of these solid compounds have been purified, a partial list follows: Diphenyl (M.P.70 0 ) was obtained in considerable quantities in the fraction boiling from 240-255°C. On standing it settled out as a white solid. This product would come from tfoo benzene molecules with the liberation of hydrogen. Durfton and Cobb have proven this to be a reversible reaction by passing diphenyl and hydrogen through a hot siliea tube and producing benzene. Napthalene (M.P.8Q 0 ) was obtained in considerable quantities, as closely as could be determined, in approximately 4 % yields on the original xylene used. In view of the conflicting reports in the literature concerning the formation of napthalene at low temper- ature and from similar liquids, toluene especially, particular care was taken in the identification of this compound. The presence of stilbene may give a clue to its formation. . . . ' • . • • • V • . . ' • • .* . t 'mm . 82 Stilbene (M.P. 124°) was found in very small quantities, apparent- ly it had been mostly condensed to napthalene. Methyl Anthracene (M.P. 198-200) mixtures of the A and B compounds have been obtained. P-Diphenyl Benzene (M.P. 207) has also been identified. Anthracene (M.P. 214-216) has been purified. 2.3 Dimethyl -Anthracene has been purified, and the other forms are also present, but so far have not been purified. A mixed quantity of trimethyl anthracene is also present. Chrysene (^.P. 248-50) was obtained in small amounts in the runs, with ethylene and xylene, under high pressures. Another compound which has been separated, is very similar to asphaltenes in its appearance , behavior toward solvents , espec- ially ether and hexane, and contains sulphur. It is not easy to determine where the sulfur came from to enter the reaction, unless it was obtained from the charcoal, metals or pumice 1 stone. No doubt many more compounds may be identified but the above list is sufficient to demonstrate the extremely complex molecular formations which were produced in these experiments. It is evident that any compound that can be synthesised from benzene or toluene by pyrogenetic decomposition, under similar conditions to the above, can also be produced from xylene, because it is capable of being broken down into similar groups or atoms or molecular formations. . • . , . ■ . • . j . > ■ - 83 IV. SUMMARY Some of the most important facts established by the fore- going investigation are given in the following summary. (1) Mixed xylenes, under favorable conditions of temper- ature, contact surfaces and pressure, can be decomposed into tolu- ene or benzene. The gaseous atmosphere most favorable to this reaction is either methane or hydrogen. (2) Under identical conditions of temperature, contact surfaces and pressure, xylenes can be built up to form naptha- lene, anthracene, and the methyl derivatives of both. The gaseous atmosphere favoring the reaction is preferably ethylene or other unsaturated gaseous hydrocarbons. (3) Metallic ^xide surfaces, especially after being slightly reduced at temperatures where they decompose xylene freely, influence to complete decomposition of the hydrocarbons to hydrogen, methane and carbon. (4) The reduced metallic surfaces, or freshly oxidized surfaces at the same temperature is much less reactive, and in- fluences to partial decomposition. (5) Non-metal li c substances such as charcoal , pumice , or refractory material at like temperatures tend to decompose xy- lenes into unsaturated and higher boiling compounds. The decom- position to carbon is materially lessened. (6) The gaseous atmosphere in which pyrogenic decomposi- tion takes place exerts an extremely important influence on the products of decomposition. Gases like methane and nitrogen between . « . . , , "• - iu . . . , 1 84 o temperatures of 600 to 700 C have only a mechanical action. Ethylene, acetylene, hydrogen and ethane between the same temper- atures have also a mechanical bearing on the end products. Their all-important action, however, is chemical, tending to produce high-boiling compounds; ethylene, acetylene and ethane were found to be entirely decomposed at temperatures above 725°C. (7) By the deliberate control of the gaseous atmosphere under which decomposition takes place, the yields of the desired products can be greatly increased. (8) Steam, air and carbon dioxide poison or deaden acti- vated surfaces, in such a way that they appear to stabilize li- quid hydrocarbons. (9) Contact surfaces are very important in hydrogenati on and dehydrogenation of aromatic hydrocarbons. (3D) Pressure under some conditions favors molecular con- densation that is, if the pressure is made up of unsaturated gases. In other cases it caused, where the pressure was made up by hydrogen, the decomposition of the heavier molecules into the single ring compounds. Pressure in all cases lessened the percentage of unsaturated hydrocarbons in the final products. (ll) Decomposition of hydrocarbons increases with rise in temperature. The larger molecules being less stable than the smaller ones at temperatures above 700°C. The lower the tempera- ture at which decomposition takes place the more economical the reaction. Lower temperatures can be used in the presence of activated surfaced. (12) Practically all of these reactions are reversible. . . I , • . .i. V‘ , , • . . . . . 85 . BIBLIOGRAPHY 1. "Application of dynamics to Physics and Chemistry" 2. Bandcroft, W. "Applied Colloid Chemistry". 3. Sabatier "La Catalyse en Chimie Organique". 4. Armstrong, H.E. Brit .Assoc .Reports 1885,962. 5. Langmuir, Irving, J.A.C.S.1916 ,38,2221 . ,191? ,39 ,1848. ,1918,40,1361 6. Harkins, W.D. , J.A.C.S., 1917, 39, 541. 7. Bertholet, M. AEIT ChemPhys. Ser . 4 , t . 9 , 1866 .pp 445-483 " » " " 4 , t .12,1867, pp 5-69 " " " " 4, t .16, 1869, pp 143-187 8. Zanetti, J.E., and Kendall M., J.Ind.and Eng.Chem.Vol .13f'3 March 1921-pp 208-211 9. Zanette, J.E., and Egloff, G. J.Ind. and Eng.Chem, 9 ,pp350 , 1917 10. Ferko.Paul, Ber .Deut . Cehm.Gesell , Jahrg.29, Bd3,pp 660-4 11. Haber, E. Ber Deut .Chem.Gesell .Jahrg.29 , Bd3. 12. McKee G.W. , Jour. Soc.Chem. Ind. Vol. 23 , 1904 , pp403-4 13. Ipatieff, V.H., J. Russ . Chem.Phys. Soc . 39 ,pp. 681 , 1907 14. Ostromisslenski , J . , an d Burschanadse , J. J .Soc ,Chem.Ind. 29 Pp682 15. S^nith, 0. and Lewcock, W. ,J. Chem.Soc.Vol .101,pt2 ,pp 1453-59 16. R i 1 1 iiia n , W. 5*. , Dutton, C.B. , and Dean ,E.W. , Bureau of Mines, Bull 114 17 Charlton, E.E., Thesis for doctor of philosophy in Shem.U of I 1916 18. Cobb,J.W. and Dufton,S.4 . ,The Gas World, Vol .72 , 1920, pp 485 19. Parr, S.W.,and 01in,H.E., Bull . 79, T J. of I Eng.Expt.Sta. 20. Parr, S.W. and Layng, T.E., L.45, U. of I .Library , 1916 . 21. Clark, J.M., J. Ind. and Eng. Chem. Vol .11 ,Ho . 3 , pp 204,1919. 22. Cook, O.W. and Chambers, V. J. , J.A.3 .C . ,Vol .43 Ho 2,pp 334,1921 23. Cobb, J.W, and Hollings, H.S. J. of Gas Lighting, Vol 126 pp 917 24. Bone and Coward, J.C.S., 1908, 93, 1917 25. Thomson J. J . , Chemi cal Hews, 1911, 103, pp. 265. 26. Clark, J.H., J.Ind. and. Eng. Chem. Vol ll,Ho.3,pp 204. 86 VI. VITA The writer of this thesis received his early education in the grade school at Leskard, and high school at Bowmanville, Ontario Canada. He graduated from McMaster University, Toronto, in June 1915, with the degree of Bachelor of arts, in the honor science course. In September, of that year, he received the degree of Master of Science from the same University. After graduation he entered war munition work. Prom Sept. 1915 to March 1916 analysing high explosives at the plant of The Canadian Explosives Ltd., Montreal. Prom March 1916 to IT ov ember of the same year analysing 9.2 inch sheel steel, at the plant of The Canada Cement Co ., Montreal . During November he was at the plant of The Armstrong-Whithworth Co . .Longui el , Quebec , analysing tool steel. Prom December 1916 to October 1917 he was with The British Munitions Board, stationed at the acetone plant, of The Canadian Electro Products Co., Shawinigan Palls, Quebec. Since October 1917 he has been at the University of Illinois doing graduate work. While here he has held the follow- ing positions in the Department of Chemistry. October 1917 to Feb- ruary 1918, graduate Assistant; and from February 1918 to the present time, half-time assistant.