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Val. 18, No. 5
Research in the Petroleum Industry’ By Benjamin T. Brooks 50
EAST41sT
ST., NEW Y O R K , N. Y.
I
N HIS popular book on “The Mind in the Making,” J. H. Robinson states that scientific curiosity is the rarest and probably the most divine thing in the world. Certainly it is the most important thing in the world, in its manifold final results, for our mental satisfactions, our industries, and our daily comfort. The attempt to promote fundamental scientific work through the encouragement of financial awards to qualified investigators is not only an attempt to encourage scientific research in this comparatively neglected field, but also to aid men who really need no other driving force than their own scientific curiosity to carry on. Such financial aids, though only palliative of the fundamentally wrong condition prevailing in universities and research laboratories-i. e., the inadequate salaries of professors and research men-will undoubtedly help many to continue in scientific work who might otherwise be unduly handicapped in their work or perhaps be compelled to give up such work altogether. The recent bequests of John D. Rockefeller and the Universal Oil Products Company through H. J. Halle, a total of $500,000, for the promotion of fundamental research relating to petroleum make it desirable to indicate in a general way a few typical lines of investigation which have been considered in the plea which has resulted in the bequests above noted. I n this paper the original intention was to deal with researches having no obvious industrial interest. This has proved to be a surprisingly difficult thing to do. However, the following discussion should be considered, not as a list of specific problems, but rather as a general discussion indicating the character of the research which some of those who have been active in furthering the promotion of research relating to petroleum have had in mind. Fundamental scientific work may easily seem to be so far removed from refinery engineering that it would appear to have no other result than to satisfy scientific curiosity. The crux of the matter is, however, that, a t least from a chemical point of view, there is so little known of the chemistry of these millions of barrels of liquid fuel that a great deal of systematic scientific work must be done, much of it with no other driving force than this divine scientific curiosity. The present plan to promote scientific work relating to petroleum is an effort to procure for the petroleum industry its share of such research, I n the present state of our k n o d edge a few lines of investigation of interest both t o the refiner and the scientific investigator are apparent, but for the most part our knowledge is so meager that the way of the prognosticator is certain to be an embarrassing one. But a continent cannot be all morass or desert, and in hundreds of research laboratories there are men imbued with scientific curiosity who ask only to be “grub-staked” to go forth like Livingstone, not to find a gold mine, but to blaze new trails. Activities Leading to A. P. I. Grants
During the course of industrial research undertaken several years ago, the writer was much impressed by the relative lack of organic chemical information pertaining to the nonPresented under the title “The Relation 1 Received March 15, 1926. of Fundamental Research to the Petroleum Industry” before the Division of Petroleum Chemistry a t the 71st Meeting of the American Chemical Society, Tulsa, Okla., April 5 to 9, 1926.
benzenoid hydrocarbons. This belief was strengthened by further inquiry and prompted the writing of “The Non-Benzenoid Hydrocarbons,” the principal thesis of which was to show, not only the fragmentary character of such information as we have, but also that the chemistry of such special and very artificially classified subjects as the terpenes and the misnamed hydroaromatic compounds was really closely related to the chemistry of other hydrocarbons not usually so classified and which in many cases are known to be constituents of petroleums. This idea was no doubt shared by many and is now very generally accepted. At the September, 1923, meeting of the AMERICAN CHEMICAL SOCIETYa t Milwaukee, the writer read a paper on “Petroleum as a Chemical Raw Material.” The attempt to deal with such a subject in a few minutes a t the end of a long program of miscellaneous papers convinced the writer of the inadequacy of such efforts to promote research in this field. Shortly afterwards, the writer drafted a plan of subsidizing fundamental scientific research relating to petroleum and communicated the plan to three of our best known advocates of the cause, H. E. Howe, James F. Norris, and Van H. Manning. Dr. Norris had already undertaken and published many researches in the field of what might be called nonbenzenoid hydrocarbon chemistry, and he quickly became an ardent champion of the proposed plan. Also Dr. Manning, since associating himself with the American Petroleum Institute in 1919, had been an earnest advocate of research in the petroleum industry itself. I n some of the earlier discussions of research relating to petroleum, the attempt was made to secure aid for research of an industrial character. Dr. Manning made an address in 1922 at the Birmingham meeting of the AMERICAN CHEMICALSOCIETY giving the research suggestions that he had collected. However, no support was ever given the American Petroleum Institute to carry out the researches suggested by Dr. Manning. It is probably too much to expect that private business enterprises turn over any definite research ideas of industrial value or promise, pro bono publico, or that the technologisti employed by these companies can be expected to do so if they have any proper regard for the legitimate interests of their employers. There are, of course, large technical problems of general interest to industry which can be very properly handled by collective or governmental agencies, such as the United States Bureau of Mines, the United States Bureau of Standards, the American Society for Testing Materials, and the American Society of Automotive Engineers, and these agencies have been active and helpful, as is well known. However, the present plan is directed essentially to the building up of a broader foundation of scientific information, much of which will be helpful in the solution of specific industrial researches or problems. It is believed, therefore, that the work contemplated in the proposed plan would be auxiliary rather than in any sense competitive to the research being done by the various units of the petroleum industry. I n March, 1924, Dr. Manning called together a committee to consider the proposed plan. This temporary committee included several men well known for their success in the direction of industrial research, three who were familiar with petroleum technology, one representative of the American secretary Society Of Petro’eum Geologistsj and R* of the American Petroleum Institute, also met with the com-
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INDUSTRIAL A N D ENGINEERING CHEMISTRY
mittee. Following the discussion by this temporary committee, the writer drafted a brief outlining the plan, its purposes, and a justification of it, including a number of definite problems to indicate in a tangible way that the work suggested was worth while. The questions before this temporary committee were essentially these: “Is it reasonable and worth while to extend our scientific knowledge of petroleum? Is it reasonable and worth while for competent investigators to give their time to it? Is it worth the money which mould be required to carry out a comprehensive plan and is the plan a practical plan from the standpoint of all concerned?” Much of what follows is taken from the writer’s brief of the matter. Extent of Petroleum Industry
For the sake of those who have not followed closely the growth of the American petroleum industry, it may be noted that about nine billion dollars have been invested in it and i t is today our second largest industry. Its products are absolutely indispensable to our civilization as now organized, and yet these materials are limited to six major productsmotor fuel, kerosene, lubricants, fuel oil, gas oil, and asphalt. The magnitude of the industry is such that even slight technical improvements affecting any of these major products would result in the saving of very large sums of money, important even to the oil industry, for, contrary to popular belief, the business of petroleum refining is not carried out with a large margin of profit. While the economic ups and downs of the business are due primarily to uncontrolled production, greater diversity of products, which is one of the inevitable ultimate results of research, will be a factor tending to stabilize the industry. Although it is inconceivable that any chemical uses for petroleum oils will ever be found which will demand as much oil as, for example, the gasoline requirement of automobiles, yet the recovery of by-products has been a great factor in changing the whole coke industry, by-product ovens now producing about 80 per cent of our coke. Similarly, the manufacture of glucose, starch, butyl alcohol, corn oil, and other products from corn has reached such a magnitude that it has become an important factor in determining the market value of our corn crop. Many other examples from other industries could be cited to show that by-products, relatively unimportant in the beginning, frequently grow to be of the greatest importance to these various industries. Petroleum is like coal in that it is consumed essentially as a fuel, and only to a relatively minor extent in other ways, as the following figures show:2
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Petroleum products are no exception to the general rule that the value of products of simple and universally understood manufacturing processes follows very closely the market value of the bulk raw materials. Under these conditions and barring illegal trade understandings to uphold prices, the obvious formula for economic success is enormous refinery throughput. It becomes all the more necessary, therefore, for refineries to install processes and equipment which will widen their normally small margin of profit, even by the smallest fraction, Thus, the recovery of an additional 4 per cent (of the crude) of gasoline by improved fractionating equipment may double the annual profits of a refinery. This has been fully discussed by others, notably by Walter Miller. The tendency of refineries to become more complex, technically, is shown by the extensive technical improvements installed during the last five or six years which are characteristic of most units of the industry. Already the simple skimming plant is an anachronism. The demonstrated technical improvements of recent years and their economic benefits to the industry were very ably reviewed in a recent symposium of the American Institute of Mining Engineers. The principal subjects considered in this symposium were recent developments in the cracking of heavy oils for gasoline, the centrifugal separation of amorphous wax, and the results of fractionation by the best modern equipment. The economic importance or saving, of the latter alone, if applied to the whole industry, was estimated by Mr. Miller to be about Sl~O,OOO,OOO annually. Nature of Research to Be Administered by American Petroleum Institute
Before taking up the relation of fundamental scientific work to the petroleum industry, it may be pointed out that the refining of petroleum for present-day products is almost wholly a matter of engineering rather than chemistry. The important advances in refinery technology of the last few years have been mostly engineering improvements. This general condition is true of any large-scale manufacturing enterprise. Yet it would be surprising if the petroleum industry would prove to be an exception to the general rule that fundamental scientific research opens up new possibilities for the engineer to adapt to large scale work. The donors of the funds given to the American Petroleum Institute for research fully appreciate this, and they are fully aware of what has been accomplished in other industries. They have asked only to be shown something more definite than general argument phrased in pretty language. There is no doubt that if scientific research can justify itself in the present instance adequate funds for its support will always Million barrels be available. Fuel oil (including gas oil and kerosene) 390 The present paper, like the brief which the writer prepared Gasoline 213 Lubricants 18 to assist in securing these funds, is aimed a t a clearer underilsphalt (from petroleum) 21 standing as to what kind of work may be carried out, to serve All of these major products are relatively low-priced ma- the purpose of these bequests. terials with the exception of the better grades of lubricants. Only a small fraction of the possibilities can be indicated With the rapid development of foreign oil fields, drilling here and, while these suggestions are naturally subject to to deeper sands, and the inevitable discovery of new fields criticism as to their value, they should be helpful to those in this country, together with many technical developments who have not heretofore given the subject much study. tending to make a given quantity of motor fuel give us more It is fairly obvious that to pass upon the merits of investigamiles per gallon, the use of tetraethyl lead and the possi- tions dealing not only with organic chemistry but with the bility of the widespread use of motors of higher compression geology and geochemistry of petroleum, colloid chemistry, ratios, the tendency t o get away from oil enrichment of water physics, physical data needed by engineers, etc., will need gas, the partial replacement of fuel oil by powdered coal, the judgment of a group of properly qualified persons, a etc., and the steady increase in the installation of cracking provision which the directors of the American Petroleum processes indicate that these major products will continue Institute can be relied upon t o furnish, to be relatively low-priced commodities for many years. While many follies are committed in the name of classification, scientific researches which may be considered in “Petroleum Supply m d Demand,” Report of the American Petroleum Institute, 1986. this connection may be grouped as follows:
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I-Geological history of petroleum. There are many questions under this head the investigation of which is considered by petroleum geologists to be helpful and of great interest to them.
in 1912, or ten years before the industry seriously took up the question.
11-Investigations having to do with present refinery products and processes. The authority exercising control of the research
grants will naturally not favor investigations, subsidized by the bequests under consideration, which would directly conflict with or duplicate those strictly industrial researches which some of the refiners are doing, or which should be left for them to do without subsidy. 111-An extensive development of the whole field of the chemistry of the hydrocarbons in petroleum and the study of individual hydrocarbons which occur in petroleum or can readily be made from petroleum could well be carried out simultaneously with other researches extending our present very limited knowledge of the hydrocarbons actually constituting the bulk of our different petroleums. IV-Study of shale oils and oils f r o m the low-temperature carbonization of coa2. When the time comes when oils from these
sources are needed and their market value justifies their manufacture, it will undoubtedly be the petroleum industry that will be called upon to commercialize them. Geological Aspects
As regards the origin of petroleum there has been a great deal of speculation and very little experimental investigation. Chemical investigation of geologically recent organic deposits, a study of the products of anaerobic fermentation of organic matter, particularly fats (which has often been suggested but never done), and further study of petroleums, especially the sulfur and nitrogen derivatives, would throw a great deal of light on the origin of petroleum. Engler’s destructive distillation of fats may be just as far from Nature’s processes as Bergius’ hydrogenation of coal at high temperatures and pressures, or the metallic carbide theory. Have the sulfur, hydrogen sulfide, and organic compounds of sulfur been derived from the reduction of inorganic sulfates by oil, or have the sulfates come from organic sulfur, or both? Bacteria are known which form and accumulate free sulfur from sulfates and others that can oxidize it. Is the sulfur content of an oil any indication of the type of hydrocarbons composing the oil? We know practically nothing of the change in composition of petroleums caused by filtration through rock strata or fuller’s earth, beyond the early work of Gurwitsch and Gilpin, Day and Cramm. Here we touch upon refinery operations also, but the industry might be saved a good deal of money if such materials as bauxites, silica gel, acid-treated clays, and the like were impartially and thoroughly investigated and the results published. Inertia of t h e Industry
It is only fair to suggest that much of the technical sluggishness of the industry is due to the fact that those in control of the business very seldom make the best use of their technical men, or give their technical men much voice as to the major operations of the refinery. To show that this criticism, of the management rather than of the technical men, is not merely an empty phrase, a few illustrations may be given. The use of efficient fractionating equipment has been practically universal in several other industries for at least thirty years, but similar equipment in American petroleum refineries has been installed only within the last five years, and even today some of our largest refineries are still without a single fractionating tower designed according to well-known scientific principles, and this even though the benefits of so doing are demonstrated to be of the magnitude stated by Mr. Miller, as noted above. Others still insist on attempting to build such apparatus on hearsay description and turn the entire matter over to the chief boiler-maker to make such a tower out of some bit of discarded scrap. The writer has personal knowledge that technical men urged the installation of such equipment, scientifically built, as soon as the need for more efficient gasoline distillation became apparent-that is,
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Vacuum Distillation Another illustration indicates this peculiar inertia of the industry with respect to technical improvements. Distillation under partial vacuum was carried out on petroleum oils back in the 1870’s and to a relatively small extent up to the present time. There is no evidence, however, that a really high vacuum was ever employed and the method gradually fell into disuse, most refiners preferring to use fire distillation aided by steam. I n the case of wax-bearing oils the desirability of firing hard to crack amorphous wax was an important consideration. The very marked effect of distilling petroleum oils under very low pressures, 3 to 5 111111. of mercury, on both the yields and quality of the lubricating oil distillates was discovered and first put into industrial practice by John E. Schulze, although the very great effect of small changes in pressure has long been known and was particularly pointed out by Krafft.3 Thus, from old results, Gurwitsch4 calculated that an oil boiling at 842’ F. (450’ C.) a t atmospheric pressure could be distilled a t 456’ F. (236’ C.) under 5 mm. pressure; or in other words, an oil having a normal boiling point so high that extensive cracking would occur if distillation at atmospheric pressure was attempted, could be distilled a t 5 mm. pressure a t temperatures only slightly above the distillation end point of ordinary Navy gasoline. This is also shown in a practical way in the results of Schulze on a heavy black car oil, showing the percentage that can be distilled a t various absolute pressures. High Vacuum Distillation of Petroleum Residuum Pressure Mm. H g 40 25 15
Per cent over a t 572O F. (300’ C.) 30 50
Initial boiling point
68
419
5
94
364
’ F.
455 437
Only a few years ago any one who proposed to distil oil under the very low pressures employed by Schulze was told that the suggestion was too academic and wholly impractical. In many refinery laboratories today a request for a small efficient vacuum pump for use in research would be regarded in about the same way as a request for a splinter of the North Pole. Fortunately, the number of such plants is rapidly decreasing and there are a few companies that have built and equipped excellent laboratories. Practice is very often ahead of theory, and in connection with many of our present-day refinery products and processes there are many unanswered questions the investigation of which would give us the “reason why” but would not necessarily increase the profits and perhaps not improve the quality. Plant laboratories cannot ordinarily afford to spend money on such “reason why” researches. Such essentially theoretical researches which the refiners themselves may not be justified in carrying out, in view of the expense and little prospect of financial return, could very properly be done under the subsidy plan now being administered by the American Petroleum Institute. Thus, it would be a great satisfaction and possibly lead to new discoveries if we knew exactly how and why tetraethyl lead suppresses knocking in gasoline engines to such a remarkable degree, and why different hydrocarbons behave so differently in this respect. Lubricating Value of Petroleum Hydrocarbons I n connection with lubricating oils it has been suggested that unsaturated olefinic hydrocarbons are selectively adB e y , 29, 1317 (1896) “Wissenschaftliche Grundlagen der 1924, p. 205. 8
4
Erdolverarbeitung,” 2nd ed.,
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sorbed from an oil and give effects very similar to those resulting from the admixture of a small percentage of free fatty acids in a mineral oil lubricant. So far as publications indicate, this has never been experimentally tested. This brings up a number of related questions, such as why does a freshly distilled lubricating oil distillate darken in color and why does acid refining correct this? Academic questions perhaps, and yet this effect may easily be due to a cause which could be much more simply corrected than by present methods. Also, we do not know whether, in the sulfuric acid refining of lubricating distillates, the acid does not do a great deal of destruction of material and damage to the remaining oil that is not necessary. When sulfuric acid acts upon such oils to produce tars, water-soluble acid derivatives, and polymers, are these water-soluble acid derivatives of the esters type, R-O-S03-H, such as we obtain from the simple olefins, or are they true sulfuric acids with sulfur bound to carbon? Our organic chemistry does not tell us. Fluorescence in Petroleum Distillates
What is the cause of fluorescence of petroleum distillates? This subject apparently has to do only with the appearance of the oil, like the trace of dye in a candied cherry, but there is a good deal of evidence that the fluorescent material consists of benzenoid hydrocarbons.6 Whenever there is such great decomposition that coke is formed, fluorescent oils result; even slight charring, as in the boiling of linseed oil will give a fluorescent product. Lubricating oils distilled a t very low pressures (high vacuum) are only very slightly fluorescent, sometimes not a t all, but the same oils distilled by fire, accompanied by partial cracking and coke formation, are highly fluorescent. Crude coal-tar distillates, particularly the intermediate oils, are extremely fluorescent. This gives us what may be a very valuable clue as to how and why coke forms in cracking processes. Those who have studied coal and coke believe that coke from coal is an assemblage of six-carbon rings as in anthracene, fluorene, pyrene, chrysene, picene, carbopetrocene, and the like, and that the effect of heating to increasingly higher temperatures is to expel more and more hydrogen with further chemical condensation or ring coupling as the coke becomes harder and denser. On the other hand, the paraffins can be cracked a t moderate temperatures without forming coke, which is another way of saying that heat causes splitting of the carbon-to-carbon bond in the paraffin hydrocarbons but in the aromatic series, in which the remarkably stable six-carbon ring structure is present, the result is chemical condensation, carbon-to-carbon combination to larger and larger molecules and eventually to coke, with the liberation of hydrogen and other simple split-products such as methane, ethylene, ethane, etc. Further evidence of the correctness of this view, that petroleum coke is formed via the intermediate formation of complex aromatic or benzenoid compounds, is furnished by the early work of Prunier6 and others, who isolated a series of such fluorescent hydrocarbons from petroleum coke. One refiner, cracking gas oil to gasoline, treats the re-cycle stock with sulfuric acid before returning it to the cracking system. I n cracking apparatus which is not adapted to taking care of large quantities of coke the removal of these coke-forming aromatic hydrocarbons in this or any other manner may greatly prolong the operating cycle, which is an example of how very practical possibilities may grow out of a research of apparently only academic or “reason why” nature. The General Electric Company was actively interested in electrons long before the development of the modern radio. 5
6
Brooks and Bacon, THISJOURNAL, 6 , 623 (1914). .4nn chim p h y s . , 151 17, 28 (1879).
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Meagerness of Knowledge of Petroleum Hydrocarbons
It cannot be too strongly emphasized that our knowledge of the hydrocarbons known to be present in petroleums is not so great as is commonly supposed, and our common textbooks of organic chemistry, in so far as they refer to petroleum a t all, are grossly misleading in this respect. Only recently the writer read the testimony of a well-known college professor, deposing as an expert witness on the subject, to the effect that lubricating oils, from which the paraffin wax had been removed, also consisted of paraffins but that there were so many of them that the melting point of the mixture was lowered to a very low degree. The old statement of the school books of forty years ago that Russian petroleum consisted of naphthenes and “American petroleum” of paraffins is certainly difficult to eradicate, and students are evidently still being taught this in some quarters. Others who like to write larger books go to the other extreme and one well-known treatise contains a catalog of practically all known hydrocarbons, including the olefins, acetylenes, terpenes, and many aromatic hydrocarbons which are definitely known not to be present in crude petroleums. Much of the earlier investigations, reporting large numbers of definite hydrocarbons, will not stand critical reading in the light of our knowledge of the complex character of these oil mixtures and the difficulty of their separation by fractional distillation, particularly in the light of the careful work of Young and his co-workers. The composition of the lighter distillates (gasoline) has an added importance a t the present moment on account of the widespread interest in the rather widely different antiknock values of different hydrocarbons used as motor fuel. Now that paraffins are known to be the worst of all types of hydrocarbons from the antiknock standpoint, i t will be easier to secure expert testimony to the effect that they are not so predominant in many gasolines as was formerly supposed. The method of extraction with liquid sulfur dioxide, used industrially in a few American refineries, has not been used as an instrument of research nearly so much as the value of the method warrants. The brief paper by C. R. Wagner on the liquid sulfur dioxide extract of light Midcontinent kerosene is particularly suggestive. Oxidation of Oils
The behavior of petroleum hydrocarbons, individually or collectively, to oxidation by a single reagent, air or oxygen, is known only partially and in but a few instances. The recent oxidation of paraffin wax by air a t about 120’ C. to fatty acids and a series of intermediate products has caused us to modify our ideas as to the relative stability of this class of hydrocarbons. Makers of so-called paraffin-base oils have been enjoying this tradition. The subject is one of great practical importance and should be thoroughly and impartially investigated. We know that the formation of resinous oxidation products in transformer oils is catalyzed by traces of metallic soaps and very probably by other substances. Also the resistance of lubricating oils to oxidation in internal combustion motors, or under standard conditions in the laboratory, and the course of such oxidation, when it occurs, to asphalts or resins and eventually to “carbon” deposits, are probably influenced more by the refining history of the oils than by the type of crude from which they are prepared. Is it possible to retard or practically prevent the oxidation of such oils by air a t moderate temperatures by the addition of a trace of something, similar to the remarkable effect of one part of hydroquinone or resorcinol to one hundred thousand of benzaldehyde? What substances, liable to be present in commercial refined oils, accelerate oxidation? What products are formed by the air oxidation of individual hydrocarbons, saturated
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and unsaturated and under various conditions? The oxidation of paraffin was to fatty acids was the first indication that anything other than the products of complete combustion could be obtained from these hydrocarbons, It has been commonly supposed that olefins are much more easily oxidized by air than the saturated hydrocarbons. Engler and Weissberg actually isolated the peroxides of an amylene and a hexylene, and altogether quite a little information of such oxidations, of olefins, has accumulated since the early suggestive work of Engler and Weissberg. Formation of gum in cracked gasoline is but a simple case of a rather well understood type of oxidation, the so-called gum varying in composition, consisting first chiefly of organic peroxides and these passing through a series of changes, depending largely upon the presence or absence of moisture, into aldehydes and aldehyde resins, ketones, fatty acids, carbon dioxide, and water. “Gum” formation is a general property of unsaturated hydrocarbons, the rate of oxidation varying widely, the diolefins being chiefly responsible in cases of very rapid “gum” or resin formation. Cracking Reactions
The properties of refined cracked gasolines, containing as much as 40 per cent by volume of olefins, indicate that though they may be oxidized slowly, with resin formation, oxidation of the pure hydrocarbons in this way produces practically no discoloration until the oxidation has progressed to a very great extent. These changes are more fully discussed in another paper, but since the simpler olefins are much more reactive than those of high molecular weight and since discoloration is not due to oxidation of the hydrocarbons themselves, it is certain that the discoloration which accompanies air oxidation of freshly distilled unrefined lubricating oil is due to impurities and probably with the development of a trace of acidity, as in the case of gasoline and kerosene. This brings up again the advisability of a thorough investigation of the chemistry of the refining of lubricating oils. Alcohols from Petroleum
The chemistry of the action of sulfuric acid on the simpler olefins has been known for several generations; yet the composition of the light acid oils obtained in refining light oils long remained a mystery. Their most aromatic and most easily identified constituents are secondary alcohols derived from the olefins. It is rather curious that the earliest attempts to manufacture alcohols by means of sulfuric acid and hydrolysis of the resulting sulfuric acid esters were made on ethylene from coal gas, and Fritsche actually manufactured ethyl ether from oil gas in Richmond, Va. A series of secondary alcohols including isopropyl, secondary butyl, secondary amyl, and secondary hexyl alcohols, and the tertiary alcohols, tertiary butyl, and tertiary amyl, are now manufactured from oil gas. It is doubtful if the primary butyl and amyl alcohols made by fermentation can compete with the secondary butyl and amyl alcohols and their esters made from petroleum, once the properties of the pure solvents are known and appreciated. The manufacture of this series of alcohols represents either the recovery of these values from the cracking-still or coking-still gases, or cracking oil for a new set of purposes-i. e., a highly efficient antiknock gasoline, a series of gaseous and light liquid olefins for conversion to alcohols, and a large proportion of residual gas which can be sold as gaseous fuel. This development, tying in such chemical processes with other engineering innovations, is a significant sign of the times. Reactions with Sulfur
Although several of the reactions that have been so useful in the study of the terpenes were discovered in connection
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with work on amylene, these reactions have not been applied to the study of olefins of cracked petroleum oils, either in the form of cracked gasoline or the pure individual hydrocarbons. Two instances are known of the addition of sulfur to the olefin bond, and in the light of the well-known use of sulfur and sulfur chloride in the vulcanization of rubber and the fact that the organic reactions of sulfur and oxygen generally are so similar, it is surprising that no work has been done on the reactions of sulfur with either pure hydrocarbons or commercial mixtures. The rediscovery of the reaction of ethylene and sulfur chloride, first noted by Guthrie, to give the well-known military weapon mustard gas is an excellent illustration of the scarcity of our knowledge in this field. The reaction of the unsaturated hydrocarbons with hypochlorous acid. with the many chemical reactions possible with the resulting chlorohydrins, has been very little studied, although Curme has successfully commercialized the conversion of ethylene to ethylene glycol in this way. Only the simpler glycols and alkylene oxides are known. Nitro Paraffins
Very little has been added to our knowledge of the nitroparaffins since the important theoretical work of Nef. Amino derivatives, particularly of the naphthenes, might be valuable as antiknock materials for gasoline. Most of those that are known have objectionable ammoniacal odors, but few of these amines are known and better methods of reducing the nitro derivatives are necessary since reduction in acid solution gives chiefly ketones and ketone condensation products, these being formed by hydrolytic splitting of the intermediate oximes. Gums
The diolefins in highly unsaturated gasolines have thus far been only a nuisance on account of extreme rapidity with which they are oxidized to so-called gum and other products. These merit much further study since they are present in gasoline made by vapor phase cracking in substantial proportions. Engler attempted the synthesis of rubber from butadiene made in this way and Norris has recently expressed the opinion that conjugated dienes from this source may eventually yield rubber in a commercial way. A discovery most needed in this connection is that of labile addition products of the conjugated dienes which will remove them from hydrocarbon mixtures and permit the regeneration and recovery of the reagent employed, and there is good reason to believe that such a method may be found. Only the simpler conjugated dienes are known. It is known that the simpler conjugated dienes can be chemically condensed with ordinary olefins-as, for example, isoprene with limonene; a whole series of modified rubbers should be possible. The mechanism of the polymerization of olefins by different methods should be studied from a theoretical standpoint. Benefits to Theoretical Organic Chemistry
Many who are interested in the great possibilities of the researches which will be aided by these bequests of Mr. Rockefeller and the Universal Oil Products Company hope that theoretical organic chemistry will be greatly enriched thereby. Such researches as the recent inquiries into the relative stability of ring structures, carried out by Thorpe and Ingold and their associates, Niewlands’ researches on the acetylenes, the influence of structure and substitution on the chemistry of the ethylene bond, extension of the Friedel-Crafts reaction to nonbenzenoid compounds, researches probing the very fundamental theories of the chemical reactions of organic compounds, should even have priority, and this opinion is shared by many who are keenly
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May, 1926
interested in petroleum chemistry. It is a fact, a matter of the actual experience of those large industries who have carried on research entirely a t their own expense, but on very
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broad lines, that discoveries of greatest industrial value come, not from petty, pot-boiling work hardly deserving the name research, but from the bold delving into fundamentals.
Effect of Pressure and Temperature on Total Volume of Partially Vaporized Midcontinent Crude' By Robert E. Wilson and H. G. Schnetzler STANDARD OIL Co. (INDIANA),WHITING,IND.
I
S ORDER to make an intelligent design of a pipe still or
of a series of heat exchangers where a moving stream of liquid is heated and partially vaporized, it is necessary to know approximately the amount of liquid vaporized, or better, the volume of vapor plus liquid, as a function of' temperature and pressure. These data cannot be determined a t all accurately either from an ordinary distillation or from a vapor pressure curve, since it is a complicated function of pressure, temperature, and composition. Attempts to estimate it by conventional methods have been found to give quite inaccurate results. On the other hand, direct measurements to cover the various combinations of pressures and temperatures met in practice are not feasible by the ordinary methods which might be employed for a single determination. This paper describes a method which has been perfected in this laboratory for determining the necessary data and presenting the results in graphical form, and gives the results obtained on a typical Midcontinent crude oil containing various amounts of water. Method
The method consisted essentially in introducing different volumes of the liquid to be tested into a previously evacuated bomb of known volume and measuring the pressures set up a t different temperatures. From the resulting pressuretemperature curves made with different ratios of total volume to cold liquid volume, it is then possible to plot another series of curves showing the ratio of total volume to the volume of the cold liquid as a function of temperature and pressure. I n arranging the apparatus it was found necessary to have the pressure gage a t some distance from the bomb in order to prevent its being affected by the temperature. The connecting tube had to be filled with a nonvolatile, oil-insoluble liquid in order to prevent any condensation of vapors therein, while the gage itself was filled with water to prevent mercury from attacking the pressure element. The arrangement of the system is shown in Figure 1. The pressure gage and the system as a whole were found to be substantially correct by measuring the pressure developed by measured amounts of water a t various temperatures. It was desired to make the measurements on samples of Midcontinent crude with several different water contents, covering the range likely to be met with in practice-in other words, up to about 2 per cent by volume of water. The first measurements were therefore made on pipe-line crude containing 0.2 per cent water. Three other sets of measurements were made on samples containing 1 per cent and 1.75 per cent water and on a sample dried by filtering through paper, taking precautions to prevent loss by evaporation. The samples containing 1.0 and 1.75 per cent water were made up by adding measured quantities of the salty water which had separated 1 Received March 23, 1926. Presented before the Divizion of Petroleum Chemistry a t the 71st Meeting of the American Chemical Society, Tulsa, Okla., April 5 to 9, 1926.
from crude to the sample of crude containing 0.2 per cent. To prevent any segregation this additional water was measured and introduced into the bomb separately for each charge. Results
The crude used in these tests gave the following Engler distillation (-4. S. T. M. apparatus for gasoline) : D i s t i l l a t i o n of M i d c o n t i n e n t Crude Water, 0.2 per cent b y volume Gravity, 35.0' A. P. I .
% 08 Initial 10 20 30 40 50 60 70
O
F.
152 252 322 405 473 558 633 690
% 08 6.0
16.0 25.5 27.5 38.0 42.5 55.0 72.0
O
F.
22 1 284 374 392 460 500 600 700
The direct results obtained from each series of measurements are shown in Figure 2 which plots pressure against temperature for different volumes charged to the still. Figure 3 shows plots based on these same results in which the ratio of the volume of vapor plus liquid to the volume of cold liquid is plotted against pressure for different temperatures. The latter figures are more useful in practical design. I n considering these figures one is particularly impressed by the large differenceproduced by the variations in the water content of the crude. This is, of course, due to the fact that water
Figure I-Apparatus
because of its very low molecular weight, expands much more in vaporizing than does oil. Thus at 300" F. and 40 pounds pressure dry crude has not expanded over 15 per cent, while crude containing 1.75 per cent water expands 1100 per cent. It is interesting to note that, while 0.2 per cent of water markedly increased the pressure at different temperatures, it does not give the rather striking bulges in the curves which are shown by crude containing 1 per cent and 1.75 per cent of water.
