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Vol. 15, No. 5
T h e History and Status of Chemistry in Petroleum Research By Carl 0. Johns RESEARCH DIVISION, DEVELOPMENT DEPARTMBNT, STANDARD OIL COMPANY OF New JERSEY,ELIZABETH, N. J.
P
ETROLEUM has played an important role in the history
good sense, for in his undertaking he sought the advice of the of many races of mankind. It was used to make mortar famous German chemist, Justus von Liebig, who furnished in the building of the tower of Babel and the ancient plans for the refinery and sent one of his assistants to aid in its records of China and Japan contain references to petroleum. erection. Natural gas was employed by these peoples for fuel and light The beginning of the petroleum industry in the United States . . before th; Christian &a: may be said to date from about 1826, when The use of petroleum is mentioned a Dr. Hildreth visited the oil springs of Ohio number of times by the old classical auand reported that petroleum had great thors, and Herodotus, writing about 450 possibilities as an illuminant. A little later B. C., tells us that bitumen was used as Seneca oil and American medicinal oil were mortar in building the walls of Babylon. put on the market and widely advertised The oil springs of the Caucasus have been as sure panaceas for most human ills. known since ancient times, and Marco Polo, As early as 1833 Prof. Benjamin Silliman, the famous Venetian traveler, writing a t Sr., of Yale College, had made a number the end of the thirteenth century, states of distillations of petroleum in glass rethat “On the confines toward Georgia torts, and he found that the distillate was there is a fountain from which oil springs light in color and the residue was thick like in great abundance and a hundred shippitch. loads might be taken from it a t one time. The oil is not good to use with food, but In 1854 the Pennsylvania Rock Oil Comis good t o burn, and is also used to anoint pany was formed for the purpose of procamels that have the mange.” Natural gas curing surface oil near Titusville, Pennconstituted the Eternal Fire of Baku, the sylvania, by the method of digging and principal city of the Fire-Worshippers. trenching. One of the prominent men in What is probably the first printed referthis company was Mr. George A. Bissell, ence to the refining of petroleum on the of New Haven. A sample of the oil obCARL0. JOHNS Pacific Coast (Peru) of this continent aptained in this venture was submitted For peared in 1569 in a book entitled, “De Las analysis to Prof. Benjamin Silliman, Jr., of Drojas De Las Indias.” This book was translated in 1596 by John Yale College. Professor Silliman made his report to Messrs. Frampton, in London, who gave it the title “Joyfullnewes Out Eveleth, Bissell, and Reed on April 16, 1855. This document is of the New-Found World.” a classic on the chemical technology of petroleum, and repreIn 1723 Peter the Great of Russia wrote to General Matushkin, sents one of the most important researches in industrial chemistry that has ever been undertaken. Since this gathering who was then stationed at Baku, to send him one thousand represents not only one of the national meetings of the AMERICAN poods of white petroleum and also to find a man who understood how to refine it. This indicates that attempts a t refining had CHEMICAL SOCIETY, but is also the occasion of the dedication of the new Sterling Chemistry Laboratory of Yale University, been made previous to this time. it seems appropriate to discuss briefly the contents and imThe art of distillation was practiced by the ancient Egyptians during their long and highly developed period of civilization, portance of Professor Silliman’s report. and the alchemists of the Middle Ages made use of the still in PROFESSOR SILLIMAN’S REPORT their endeavors to find the elixir of life. It is not strange, therefore, that distillation was employed early in refining petroProfessor Silliman states that the sample of oil which was leum for medical purposes. It is certain that petroleum was disgiven him for analysis had a dark brown color with a green or tilled in Russia in the eighteenth century and probably earlier, blue fluorescence. When it was exposed for a long time to the for Johann Lerche, who visited the Caspian district in 1735, found that the crude Caucasian oil required distilling to make it satis- air, it did not form a skin on the surface, and for this reason could not in any way be regarded as a drying oil. The specific factorily combustible, and that when distilled it yielded a bright yellow oil resembling a spirit, which readily ignited. As early gravity of the oil was 0.882. It gave off vapors at temperatures slightly above the boiling point of water. It took fire with as 1823 the Dubinin brothers erected a refinery in the village of Mosdok. This is said to be the first attempt to make kerosene difficulty and burned with a very smoky flame. Between the fingers it felt slippery and fatty. Chemically, it differed from from petroleum. the fatty oils. Naturally, the question was-what commercial I n 1846 Prince Woronzoff sought the aid of the Caucasian government in extending the use of petroleum distillates. In value did it have and what use could be made of it. Silliman’s investigation gave the answer to this question. his petition he describes the use of an iron still set in brickwork, The oil was distilled into fractions in order to find out what and from a working charge of forty “buckets” of crude oil he obtained a yield of sixteen “buckets” of white naphtha. The products might be obtained therefrom, and the temperature was top of the still had a removable head connected with a condenser carefully noted by means of a centigrade thermometer during the distillation. The heating was first carried out by means of consisting of a copper worm in a barrel of water. About the year 1850 Baron Thornau built a plant for refining a water bath, then by a bath of linseed oil. The lighter fractions were light in color, while the heavier fractions were dark and Russian petroleum. Thornau seems to have had unusually
May, 1923
IKDUXTRIAL AiVD ENGINEERISG CHEMISTRY
had a strong empyreumatic odor. The specific gravities of the different fractions were found to range from 0.733 to 0.7854. On redistilling these fractions Silliman noticed that they began to boil below their original initial boiling points, and that the end-points were very much higher than the original. He states that the variation in the boiling points showed that these distillates contained a mixture of many different products, and he brought up the question as to whether or not these products existed in the original crude or were formed by chemical changes during the distillation. He says that temperature alone is sufficient to change the constitution of a large number of organic compounds and to produce new compounds which are not present in the original substance. After the first distillation all fractions contained a very small quantity of free acid. This acid could be removed with weak alkali and water, or by simply boiling with pure water. The distilled oil did not attack clean copper, which showed the absence of corrosive properties and therefore indicated that it could be used for lubrication. It did not contain oxygen and had no effect on clean potassium. It decomposed strong sulfuric acid, which likewise decomposed the oil. Nitric acid changed it to a yellow, oily liquid. Hydrochloric, chromic, and acetic acids did not change the oil. Metallic oxides did not convert it to a drying oil. It did not attack potassium at a high temperature. Potassium, sodium, and calcium hydroxides had no action on it, nor had calcium chloride or other salts. When distilled with chloride of lime it gave a product which resembled chloroform. The oil was investigated to ascertain if it could be used for the manufacture of illuminating gas. An almost pure hydrocarbon gas of the highest illuminating power was obtained. He states that one can, in fact, regard the oil as chemically identical with light in a liquid form. Ten cubic feet of gas were obtained from one pound of oil. This gas burned with an intensive flame and smoked with an ordinary gas burner, but gave a very pleasing flame with the Argand burner. Distillation a t higher temperature was carried on in a copper retort which held from five to six gallons. The heat was raised rapidly to about 280' C. It was finally carried up to 390' C. (750' F,), and in order to get this temperature it was necessary to heat the retort with dry walnut wood. When the last fraction was cooled, there was obtained a thick mass of pearly crystals which were paraffin. These crystals could be separated and obtained as a white substance and from it beautiful candles could be made. Silliman believed that the paraffin did not exist as such in the original oil, but was the result of the high temperature during the process of distillation which caused a new arrangement of the elements. Silliman also distilled his oil with superheated steam. The result of the various distillations a t higher temperature gave a yield of over 90 per cent of the whole product, consisting of a series of oils with valuable properties which seemed to be useful for illuminating and lubricating purposes. A second distillation of a part of the higher fraction which had been distilled a t 343' c. gave a thin oil with a specific gravity of 0.75. About 50 per cent of the crude oil could, by distillation, be used for illuminating purposes without any further treatment than the simple purification of boiling with water. Silliman made a systematic investigation of the distillates that he had obtained for the purpose of ascertaining their illuminating value. In this investigation he made use of the various kinds of lamps which were then available in order to obtain the intensity of the illumination produced. At that time gas sold in New Haven a t four dollars per thousand cubic feet and whale oil for two dollars and fifty cents a gallon. The distillate which Silliman obtained from his petroleum gave a better light than any other substance which was used for illumination a t that time.
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Silliman's report not only brought out the economic value of petroleum, but furnished information on the chemistry of petroleum which is of fundamental importance in modern refinery practice. Notwithstanding the information furnished by Silliman, the Pennsylvania Rock Oil Company was not successful, because the cost of obtaining the crude oil was too high. Mr. Bissell was, therefore, left with the Titusville property on his hands. However, in 1857 he conceived the idea of drilling through the rock for oil in the same manner as that used in drilling for brine. He did not have the necessary capital to carry out his idea and therefore formed a small syndicate in New Haven to work the Titusville oil lands. Edwin , Laurencine Drake was appointed director of the work. The result was the drilling, in 1859, of the Drake well, which yielded about twenty-five barrels of oil per day. The success of this venture spread like wildfire and in a relatively short time drilling operations became common and there was a large production of oil. This oil, however, would not have had any appreciable economic value had it not been for the fundamental researches made by Silliman, which laid the foundation for a process of refining it and slowed the important uses of the products. From the small production of the Drake well the American oil industry has grown so that in the year 1922 the United States produced 551,197,000 barrels, or 64.7 per cent of the world's production. Mexico, largely through American initiative, also contributed 185,057,000 barrels, or 21.7 per cent of the world's output, making the total production for the United States and Mexico 736,254,000 barrels, or 86.4 per cent of the world's output for the year 1922. RECENT RESEARCH' Since the days of Silliman, petroleum research has lagged behind the rapidly growing industry. This is partly due to the manner in which the industry has developed. For many years the manufacturing problem was comparatively simple. The principal products of the refinery were kerosene, lubricating oil, and paraffin wax. Gasoline was then a by-product for which but little use could be found, and most of it had to be wasted. There was, therefore, no incentive borne of necessity in the industry for research of a fundamental nature. The first serious chemical problem of the industry came without warning when the Lima oil of Ohio was discovered. This oil could only be used for fuel purposes on account of its high sulfur content and its terrible odor. Canadian oil was of the same type. The problem of refining these oils was finally solved by Herman Frasch, who found that the sulfur and vile smells could be removed by heating the oils with copper oxide during the process of distillation. The researches of Frasch increased the value of these oils about seven-fold almost immediately. Petroleum research has attracted a relatively small number of chemists comparkd with the large army that has been engaged in research on coal tar and its derivatives. Nevertheless, the scientific investigation of petroleum has not been entirely neglected. During the last tifty or more years there have always been one or more of a small group of American chemists engaged in fundamental research on petroleum. Among these pioneers ?&e in the United States are Warren, Mabery, and C@a+esnb published work of thesemen and. their co-workers ha$$K*'n Qs most of the infor -%whichwe have on the chemistry of American petroleums an& also to a considerable extent on foreign petroleums. Professor Mabery has lately been a t work on an investigation of the nondistillable fractions of petroleum. Considerable work has also been done abroad, especially in England, Germany, and Russia.
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The results of these investigations reveal that petroleum is composed almost entirely of hydrocarbons, but of several different series. Our knowledge is chiefly confined to fractions boiling below 120” C., although certain individual compounds have been isolated from the large number existing in the fractions boiii&g between 120’ and 300’ C. Very little is known concerning tk-eompounds i n the fractions with higher boiling points. ili COMPOSITION O F PETRdLEUM The chemical composition of petroleum varies greatly with the region in which the oils are found. It is possible to give here but a very brief review of the compounds which have been isolated.
PARAFFIN SERIES(CnHzn+z)-Compounds of this series are found in the lighter fractions of almost all petroleums. Nearly all the members of this series, including many isomers, from methane to nonane, have been isolated from various types of light petroleum distillates. These, with the exception of methane, ethane, and propane, are present in and constitute the major portion of gasoline. They are also found in natural gas, and this is the source from which they may be most easily fractionated in commercial quantities. Five isomeric hexanes have been found in petroleum-normal hexane, methyldiethylmethane, diisopropyl, propylisopropyl, and trimethylethylmethane. At least six heptanes have been identified. Only two of the many octanes have been isolated, and the same is true of the nonanes. In fact, we know but little concerning the composition of the paraffin fractions having boiling points higher than the heptanes. This means that most of our knowledge is limited to the paraffins constituting gasoline, the average molecular weight of which is about that of octane. If we assume that the average yield of gasoline from crude petroleum is about 20 per cent, we are faced with the fact that the composition of the remaining 80 per cent is almost unknown. OLEFINSERIES (CnHzn)--.Members of this series are also said to be present in small quantities in some petroleums. Engler, however, seems to think that olefins do not exist in crude oils, but are formed during the distillation. Among the olefins which have been isolated from petroleum distillates are hexylene, heptylene, octylene, a nonylene of unknown constitution, decylene, tetradecylene, and some others of unknown constitution. Distillates made by the cracking process may contain high-percentages of the olefins. The same is also true of distillateqmade from shale oil. li.r
N ~ S(CnHZn-z)-That
t h e s g compounds may be found in petroleum distillates is indicated by the isolation of hexadecylacetylene from an Ohio oil. BENZENE SERIES (CnHzn-a)-This series is well represented in a number of different petroleums from various parts of the world. Among the compounds of this series which have been isolated are benzene, toluene, the three xylenes, mesitylene and pseudocumene, ethyltoluene, durene, and isodurene, diethyl benzene, m- and p-cymene, diethyl toluene, isoamyl benzene. The dicyclic and tricylic compounds, naphthalene and anthracene, and some of their derivatives have also been found in petroleum. Cvcto PARAFFINS OR POLYMETHYLENES (CnHzn)-These compounds are present in a variety of oils from different parts of the world. They are called “naphthenes” by petroleum chemistsi Among those isolated from different petroleums are cyclopentane, methyl cyclopentane, dimethyl- 1,l-cyclopentane, dimethyl- 1,X-cyclopentane, cyclohexane, hexahydrotoluene. 2% pumber of other hydrocarbons of this series, such as cycloheptane, cyclo-octane, and cyclononane, and derivatives of these have been isolated, as well as many similar compounds of un-
VOl. 13, No. 5
known constitution, which have the general formula C,,H*,, and probably belong to this series. The heavier lubricating oils are supposed to consist mainly of cyclic compounds of the general formulas CwHzn-2, CnH2n-4, CnHzn-*,up to C,Hzn-20. The heaviest oils contain compounds of very high molecular weights. Mabery has recently made an extensive investigation of such oils and has found compounds or groups of compounds of such general formulas as CnHZn-s and C,Hz, - 20, represented, respectively, by C I Z Z H and ~ ~Ctt~H~24, ~ or molecular weights of 1700 and 1688. The determination of the constitution of compounds of such high molecular weights is no simple problem. SuLnuR-Sulfur occurs in petroleum in a free state, as hydrogen sulfide, or in combination with carbon and hydrogen. Mabery has made a study of the sulfur compounds in Canadian and Ohio oils, and from the Ohio oils he isolated a series of compounds of the general formula CnHznS. CsHleS and ClsHasS are examples of this type of compounds. Alkyl sulfides, such as ethyl sulfide, (C2H&S, are also found, and a number of these have been isolated. There are present also other sulfur compounds which have not been isolated and which do not give reactions characteristic of the thiophanes or alkyl sulfides. NITROGEN-Nitrogen is preserit in petroleum from traces up to 1.5 per cent. California oils contain a relatively high percentage of nitrogen. This exists in basic compounds that have an odor and some other properties resembling the pyridine bases. Mabery has shown that if the average composition of these bases is C I O H ~ ~some N , California oils might contain from 10 to 20 per cent of pyridine bases. OIL-CRACKING PROCESSES Although Silliman discovered, as early as 1855, that petroleum can be cracked, the first cracking process which was successful in producing gasoline on a large commercial scale was that worked out by Dr. Burton and his associates, of the Standard Oil Company of Indiana. This process consists essentially in heating gas or fuel oil under a pressure of about ninety pounds per square inch. This process has been so successful that through its use 750,000,000 gallons were produced in 1920. A more recent process of cracking, developed by the Standard Oil Company of New Jersey, is known as the “tube and tank” method. In this process the oil is heated in tubes and then transferred to insulated steel tanks, where it is kept a t a high temperature and pressure for a sufficient length of time to allow the necessary cracking to take place. All the cracking processes now employed for making gasoline produce a considerable quantity of fixed gases, which consist of saturated and unsaturated hydrocarbons. Working under assigned patents the Standard Oil Company of New Jersey has developed and is operating a process of making higher alcohols from the olefins that are found in these fixed gases. Among the alcohols produced by this method are isopropyl, secondary butyl, secondary amyl, secondary hexyl, together with small quantities of other higher alcohols. The laboratory researches which have been made on the chemical constitution of these alcohols indicate that they are all normal chain alcohols with a hydroxy group on the second carbon atom. This development has placed on the market a series of higher alcohols, all of which have hitherto been exceedingly rare, and as a result a number of these have already found important commercial uses. Dr. Ossian Aschan, of Finland, has also produced higher alcohols on a laboratory scale by chlorinating paraffin hydrocarbons, changing the chlorides to acetates, and then hydrolizing the acetates, In this way he has obtained a number of higher alcohols from petroleum. This process, however, is probably too costly to find commercial application.
INDUSTRIAL A N D ENGINEERING CHEiWISTRY
May, 1923 POSSIBILITIES OF
PETROLEUM
RESEARCH
The courses in organic chemistry given in most of our universities devote but little time to the petroleum industry. A wellknown textbook on organic chemistry which is used internationally allocates but two of its six hundred pages to the subject of petroleum. The industry needs a systematic study of the chemical composition of petroleum such as has been made of coal tar during the last fifty years. The problems, however,
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are of far greater complexity than those encountered in the investigation of coal tar. Petroleum affords a veritable mine of organic compounds. The magnitude of the industry is such that petroleum research should attract the best trained organic and physical chemists in our universities. Who can ptedict how far reaching both from economic and scientific aspects would be the results of a thorough scientific investigation of this almost virgin field?
T h e Chemist Enters a New Industry’ By H. E. Barnard
of war time was one that made bread stay IVF, or ten thousand years ago a sold. Once it reached the grocer it went primitive baker pounded up a handon to a customer-not back to the shop the ful of cereal grains, wet the mass, next day, if it was unsold. Out of the chaos and baked it on a hot stone. In the course which confronted every baker emerged of centuries he improved his process somean industry with a vision of the value what. He sifted his flours, he arched his of science, of the need of the chemist in hot hearthstone. One day he made up too the shop. T o be sure, the vision was folarge a batch of dough and left some of cused on practical things-on better buying i t unbaked. After the manner of aough, methods, on relative values of materials, it became food for yeasts and fermented. on the fitness of shortenings, sirups, sugar, The next bake was leavened bread, and and salt for their particular purpose. But after years of casual handling of sour dough, fortunately, a chemist once installed in a yeast-raised bread became the basic food laboratory is like a camel’s nose under a of most civilizedlpeople. But after thoutent. Before long he makes the whole sands of years of skilful craftsmanship plant his laboratory. bread baked but a few decades ago was So it has been a t the bakery. To-day, made in the same way as it was in the the paking of bread is a chemical process valley of the Nile when King Tut was put with physical and biological aspects, carinto storage; as it was when the bakers of ried out in huge laboratories filled with Pompeii fled before the descending ashes automatic machinery operating under temof Vesuvius; as it was when our Puritan perature, humidity, and time control. ancestors poached the Indians’ corn cribs H. E. BARNARD And here is where my story begins. and made the first New England johnny Come with me t o this newest of industrial laboratories where a new cake. school of chemists makes its daily bread. All materials are bought Is it safe for me to say here within a stone’s throw of all the world’s history entombed on Yale campus, that baking science on specifications. Flour brands mean nothing except in their ability to produce a good loaf of bread. In other words, such flour has developed more in the past ten year.; than in all the previous years of man? And dare I say that a few baking chemists conforms to the standards of gluten quality, which measures working under little appreciated difficulties have in these short strength; of ash content, which is the gage of milling efficiency; of moisture, which so influences the absorption of water-carrying cayears overthrown the craft control of a hundred centuries and pacity and which is much cheaper when drawn from a tap a t the built a scientific industry which is doing the baking OF the world bakery than when freighted half-way across a continent in a flour in great laboratoriec, more economically and far better than sack; of color, which means high milling standards, or bleaching, ever before ? To be sure, chemists have helped the miller buy wheat for or both; and of hydrogen-ion content, which some chemists believe his grinding for many years. They have more or less stmidly is a better indication of Hour maturity and adaptability for successful use than high protein or low ash. and empirically evaluated flour by weighing ashes and digesting Milk is an essential ingredient of modern bread. From a proteins. They have given assistance to the brewer and distiller, turned yeast-maker for the baker. But their routine nutritional viewcoint it plays a role second only to that of flour we measure developments in service never unlocked the secrets of fermentation nor solved itself. And every month-for baking chemistry by months now, instead of years-more milk the mystery of gluten. And then came the Great War and days that were wheatless and, so far as the baker was con- is going into the formulas. What kind of milk comes into the stock room? What is its fat content, its acidity, its sugar cerned, two years crowded with enough grief to make a lifetime content? And is the salt worth its cost? Is there any ground miserable. He gave over the operation of his shop to the minions for the salesman’s argument that his particular salt is sweeter of the Food Administration. He learned that bread could be made without flour-or much of it-that there were other ways than competing brands and that the baker can use more of it? Are the diastatic malt sirups really diastatic, and how much? of feeding yeast than with sugar, that lard wasn’t a necessity, that poor materials properly handled would make rather good What about the yeast foods-do they contain talc? And the shortenings-are they true fats or doped mixtures of glycerol, bread. Then, too, he learned the need of making bread that alum, starch, and water? Is the yeast alive and eager to popuwould not get stale over night, for among the hampering rules late the dough batch with its virile progeny, or is it weak and 1 Presented as “The Baker Turns t o t h e Chemist.”
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