NEWER PRODUCTS from
PETROLEUM*
GUSTAV EGLOFF Universal Oil Products Co., Research Laboratories, Chicapo. Illinois
A partial list of the amazing array of present petroPetroleum i s found at depths i n che earth varying from a few feet to over two miles. Oil-bearing territory i s leum products would include not only the more familiar distributed geographically over the whole face of the globe. gasoline, lubricating oil, fuel oil, aspl& wax, and coke, Oil refining employs temperatures from refrigeration all impoved over the past few years; but seoeral less wellrange to over six hundred degrees Centigrade. n/loreover, known products, such as liquefied gases for fuel, fiolycatalysts have been perfected for use i n accelerating spe- merized products, such as gasoline, lubricating oil or cialized reactions, so that ihe properties of the products resins, and alcohols of many kinds, as well as complex chemicals useful i n our chemical industries. to be obtained are determined within definite limits.
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Kettleman Hills, California, New Mexico, and Turner Valley, Canada, yield almost colorless crude oil which is practically pure gasoline. Some Pennsylvania crude oils are nearly pure lubricants, while others are rich in paraffin wax. The vast volume of crude petroleum produced in the world, amounting to twenty-three billion barrels * Presented before the Division of Chemical Education a t the since the beginning of the oil industry, is rivaled only eighty-fifth meeting of the A. C. S., Washington, D. C., March by its variance in appearance, quality, odor, and use28, 1933, as a contribution to the symposium on "Recent Defulness. Yet all this crude oil would not fill a hole velopmcnts in Various Chemical Industries." 524
ETROLEUM as it comes from the ground, or crude oil as it is called, is far from being a standard material for which a set of "average properties" may be outlined. Black, almost solid asphalt is crude oil as obtained from fields such as Casmalia, the Kern River, California, or Panuco, Mexico, while
gallons of motor fuel in automobiles, airplanes, and other devices using internal combustion engines. The gasoline which nature provides in the crude oil itself, however, has become less and less satisfactory for the improved models of cars, chiefly because i t knocks badly in the new high-compression motors. In place of this gasoline we now have a highly satisfactory antiknock product obtained from crude oil or any of its fractions by what is known as the cracking process. Cracked gasoline is a synthetic product obtained by the action of heat and pressure on crude oil, or any of its fractions, so as to convert the molecules into those boiling in the gasoline range (35' to 210"). The cracking process has made i t possible to obtain over seventy per cent. of antiknock motor fuel from a crude oil which originally contained about thirty per cent. of low-grade gasoline. The extent to which advances in cracking have kept pace with the automotive industry is well illustrated by the ratio of the consumption of cracked gasoline in the United States to the total gasoline used. About twenty years ago practically all gasolme was produced by "atmospheric" distillation of crude oil. Ten years later, almost twenty-five per cent. of the motor fuel used in the United States was cracked gasoline, and the proportion has increased steadily until, today, i t represents forty-seven per cent. of the gasoline produced from crude oil. The quality of motor fuels has been definitely improved so as to give better motor-car performance, easier starting, speedier pick-up, faster get-away, more miles per gallon, and smoother operation. Improvement in antiknock value in terms of octane number has averaged about three numbers during the past year alone. Present-day regular-grade gasolines of 70 octane number are available, particularly in the eastern market. This quality of motor fuel will give satisfactory results in more than ninety per cent. of the cars now on the road. The increased starting speed of motor cars made possible by high-quality gasoline has in itself been equivalent to the widening of our highways or the building of "double-deck" streets. It has relieved congestion, particularly on citystreets. In the struggle to make better antiknock gasolines, higher and higher temperatures of cracking are being used, with the result that more and more unsaturated hydrocarbons of the diolefinic type are formed. These are extremely sensitive to oxidation, ;,forming peroxides, aldehydes, acids, and ketones, anddinally gums or resins. Hand-in-hand with progress in making antiknock gasoline has gone development of means for preserving its quality during storage and preventing the formation of troublesome gum. These ends have been accomplished by the discovery nnd perkction of so-called inhibitors, which prevent or check the reaction of air with the sensitive unsaturated hydrocarbons in cracked GASOLINE gasoline. Thus they prevent any gum formation durGasoline continues to be the most important and ing storage, or when the fuel is burning in the motor. most widely used petroleum product. In the year The d&elopmeut of inhibitors to prevent oxidation 1932, the United States alone consumed 18,000,000,000 of gasoline made it possible to save millions of dollars a
in the ground one mile square and one mile deep! Petroleum is found in the earth a t depths varying from a few feet to two miles. Oil-bearing territory is distributed geographically over the whole face of the globe, in arctic and in tropical climes, in deserts and under large bodies of water, in thickly populated districts or in open country, in valleys or high on the mountain side. The colors of crude oil vie with the tints of the rainbow. In transmitted light they range from cheny, amber, yellow, green, and shades of red-brown to dense black; and, under reflected light, some of them show marvelous fluorescence. Nor are crude oils uniform with respect to the odors they emit. Some are pleasant, others nauseating; some are sweet, vile, offensive, or strange and exotic. Oils with an odor of sandalwood have been found in Cuba, and one from Trinidad smells stron~lyof turpentine. An Assam petroleum emits a strong odor of camphor, while some oils are practically odorless. Other properties of crude oil vary as widely as do the color and odor. Such, then, is the difficult "raw material" from which the many products of the petroleum industry must be made. The art of petroleum refining has grown far beyond its original relatively simple separation process. The basis of refining is still a process of distillation whereby the fractions of crude oil are separated, to be applied in the several ways to which each is best fitted. Improved methods of distillation, however, have grown apace through the years, and the number of products obtained from petroleum has greatly increased. Not only has crude oil been separated into fractions with narrow boiling ranges and specialized properties, but entirely new products have been synthesized. The art of petroleum distillation is no longer limited to boiling under atmospheric pressure, but has been expanded commercially to a range of pressure from a few millimeters of mercury to hundreds of pounds per square inch. Oil refining employs temperatures from refrigeration to over six hundred degrees Centigrade. Moreover, catalysts have been perfected for use in accelerating specialized reactions so that the properties of the products to be obtained are determined within definite limits. A partial list of the amazing array of products obtainable from petroleum a t present would not only include the more familiar gasoline, lub&ating oil, fuel oil, asphalt, wax, and coke, all of which havebeen improved over the past few years, but would also cover a number of less well-known products, such as liquefied gases for fuel, polymerized products, such as lubricating oil or resins, and alcohols of many kinds, as well as complex chemicals which are useful in our chemical industries.
year which would otherwise be spent for chemical treating agents. By adding inhibitors in the merest traces, further gasoline treatment may he eliminated or modified, thereby reducing gasoline loss, preventing gum formation, and preserving antiknock properties, as well as producing a better all-around motor fuel for the modern automotive engine. LUBRICANTS
Developments in the airplane and automotive industries demand not only antiknock motor fuels, but also lubricating oils of special properties. Enormous speeds and new-type mechanical parts call for lubrication which will withstand high operating pressures and temperatures and yet not interfere with smooth operation. To meet the modern lubrication .demand, careful selection of crude oils is essential. Crudes vary widely, even when they come from different wells in the same oil field. Consequently, crude oils from particular wells in an oil field are specifically segregated, in many cases, for their lubricating-oil qualities alone. There have been many improvements in the process of refining. Oils are distilled under vacuum and closely fractionated. Vacuum distillation, under pressures as low as a few millimeters, is being used commercially for this purpose. Low temperatures of refrigeration are employed to freeze out wax from the oil, while, on the other band, development of inhibitors to prevent the formation of crystalline wax in lnbricating oils has obviated the necessity for going to such low temperatures. Solvent extraction, too, is being used to remove selectively from the oil those fractions having the best lnbricating quality. The watchword of the age, however, is synthesis and the oil industry is ultra-modem in this respect. We no longer depend solely upon the natural lubricating qualities of fractions of crude oil, for by synthesis the type of product desired may be produced from many oils naturally poor in lubricating components. More progress has been made in the manufacture of lubricating oils in the last few years than in the preceding thirty. The highly unsaturated hjdrocarbons produced by the cracking process have proved to be excellent raw material fo; synthesizing iubricants. Polymerization of such hydrocarbons with aluminum chloride is being carried out on a commercial scale, yielding products the properties of which may be controlled to a nieety to suit the most severe requirements. The hydrogenation process, carried out under 3000 pounds hydrogen pressure and a t high temperatures in the presence of catalysts, is another commercial means of synthesizing lubricating oils which are highly resistant to breakdown under service conditions. One of the present trends in automotive design is toward lower body styles to facilitate higher speed and greater acceleration on the road. In order to maintain the necessary road and body clearances, smaller rear axles are required; and because of this trend
toward smaller gears, higher tooth pressures and rubbing velocities, a point is being rapidly approached where rear axles cannot be lubricated with ordinary petroleum in a satisfactory manner. Hypoid gears operate under conditions of higher rubbing velocity than spiral bevel gears, and car manufacturers have found it necessary to provide special lubricauts. New "extreme-pressure" lubricants, made up of blends of petroleum oils, saponifiable oils, lead soaps, and sulfur or sulfur chloride have been developed for such mechanisms. The necessity for specialized products, and consequently for the development of processes to obtain them, is readily understood when we realize the speeds a t which this age has traveled. Airplanes hurtling through the air a t the almost unbelievable pace of 400 miles per hour, automobiles achieving speeds of 270, while the ordinary motorist drives readily a t 75 or 80 miles per hour, speedboats skimming over the water a t 120-all these convert our once vast continent into a neighborhood. Few of us realize the vast difference between the lubrication requirements of an engine driven a t 65 miles an hour and one driven at 35. Up to 35 miles an hour, lubrication affords few problems. But a t 65 the difficulties are greatly increased, and the punishment of lubricating oils is enormous when a motor is called upon to drive a plane through the air a t over 400 miles per hour. Motor cylinders become fiery furnaces with temperatures of over 3000 degrees Fahrenheit produced by burning gasoline. Pistons in the cylinders move a t 10,000 revolutions per minute in some motors. Under these grueling conditions the lubricating oil must not materially change its viscosity or develop carbon to choke the cylinders. It must also have fluidity which will permit the motor to start readily a t arctic or desert temperatures. The high speeds of the present day bring an element of real danger from excessive wear of moving parts, unless they are carefully protected. The new lubricants provide against such danger and insure comfortable,. dependable transporta. tion. .. A relatively recent development in the oil industry is the so-called "lubricated gasoline'' or "top lubricant." It com~risesthe introduction of a fraction of less than one per cent. of lubricating oil, oxidized oil, or mixtures thereof to gasoline. A large number of substances have been tried a t various times for such "top lubrication," including graphite suspensions, mixtures of castor oil and nitrated or chlorinated compounds, mixtures of animal or vegetable oils, etc. A much more successful type of top lubricant, however, constitutes the addition of an oxidized material to lubricating oil or partial oxidation of the lubricatiq oil itself. Some lubricated gasolines have been found, after testing, to give noticeable improvement in power with decreased fuel consumption, to the extent of about five per cent. operating the car with open throttle. Oxidized hydrocarbons have long been used in railroad lubricants, apparently resulting in low surface tension 1
or greater oiliness, so that they stand up under heavy load conditions. Of even greater importance, from a . practical standpoint, is the fact that the adhesion of this type of lubricant to the metal surface of the cylinder is extraordinary and the oil will stand up a t higher temperatures than is the case with usual lubricants. This can readily be observed from the oil remaining on the stems of exhaust valves when lubricated gasoline is used. I t is old practice to add lubricating oil to gasoline in the process of tuning-up new motors, usually over the period of the first 1000 to 3000 miles. The automotive engineer has emphasized through the years and has so designed his motors that, except for that brief tuningup period, a minimum of lubricating oil reaches the combustion cylinders during operation of the motor. At present there is literally a wave running through the oil industry in working out satisfactory substances which can be added to gasoline for the -purpose of "top lubrication." A striking 10,000,000 mile test on the use of "top lubes" in Grevhound buses has been re~orted' as follows: The Greyhound fleets have used two t y p s of lubricants in gasoline. One is an oxygenated Pennqylvauia oil processed in such a way as to form certain synthetic compounds resembling natural fats and claimed to have a high degree of oiliness. The other product also is a synthetic lubricant.. . . . . . Results observed due to the addition of top cylinder Lubricant to gasoline for heavy-duty bus engines, are: 1. Increase in gasoline mileage from 4 to 8 per cent. 2. Increases in crankcase oil mileage cumulatively to as much as 100 per cent. 3. Reduced carbon formation. 4. Prevention of frozen piston rings and sticky valves. 5. Reduced valve grinding. 6. Reduced run-in time on engines after overhauls. FUEL OILS
The development of synthetic furnace oil, Diesel oil, and fuel oils from the cracking process has reached a high point. It is a striking fact that during part of last winter some cracking units were operated to produce furnace oil and fuel oil rather than gasoline. The market value, particularly of furnace oil, was higher than the price that refiners received for gasoline. For the same reason, in Canada one refiner operated his cracking unit to produce the maximum amount of tractor fuel rather than gasoline. Furnace oil and tractor fuel produced from %e cracking process surpass the corresponding products obtained by atmospheric distillation of the crude oil, in such properties as viscosity, cold test, and B.t.u. content per gallon. Cracked fuel oils from the processing of petroleum are especially important for the reason that their viscosity does not change much with temperature, allowing ready atomization to produce a steady, closely controlled heating effect. The B.t.u. content of cracked residues is approximately ten per cent. higher on a volume basis than uncracked fuel
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CHATPIBLD, National Petroleum News, Feb. 8, 1933, p. 51
oil derived from the same crude oil, while the low viscosity and cold test of the cracked product add to its excellence. The use of fuel oil in railroads, steamships, and battleships is ncreasing a t a rapid rate. The importance of cracked reoidue for these uses lies chiefly in the fact that it saves space. This fuel used in a locomotive will take it ten per cent. farther on its way, while a ship gains a ten per cent. greater cruising area or saves ten per cent. of the bunker space. A similar advantage in greater heat content for a given volume is obtained with cracked Diesel fuels. Here, again, the saving of space is expected to be especially valuable when Diesel airplanes come into use. ASPHALT
The first known form of petroleum was called bitumen in ancient times and was what we know today as asphalt. The bitumen of the days before the oil industry was probably formed by natural evaporation of all the lighter parts of a once-liquid crude oil. Until a very few years ago, petroleum refiners obtained asphalt as the residue of distillation of asphaltic-base crude oils. It is no longer necessary, however, to depend entirely upon asphalt crudes for this product. An interesting development is the formation of asphalt from fractions of Pennsylvania crude oils containing no asphalt, or from Mid-Continent crude oils which do not yield asphalts in commercial quantities. The production of asphalts from such nudes may be accomplished through the medium of the cracking process. Ordinarily, cracking is considered a decomposition or breaking-down process; that is, higher boiling and higher molecular-weight hydrocarbons are converted by pyrolysis into hydrocarbons of lower molecular weight and lower boiling point. These reactions, accompanied by dehydrogenation, polymerization, and condensation, result in the formation of hydrocarbons having the characteristic properties of pitches or asphalts. Dependent upon the type of chargingstocks-which may range from gasoline, naphthas, kerosene, gas oil, wax distillate, or fuel oils, to the whole c r u d e a n d the pressure, time, and temperature employed, synthetic road oil, flux oil, or asphalt may be produced. These products have been found particularly useful for roadmaking purposes. One of the recent ways of using asphalt is in the form of an emulsion. Bituminous emulsions, as used in road construction, are dispersions in water of finely divided particles or globules of asphaltic material, stabilized by a protective colloid or emulsifying agent. Among the new uses for bituminousemulsions is their application in the curing of concrete, where the emulsion is poured onto the freshly made concrete. Such emulsion is also used as surfacing to get rid of the usual glare from concrete roads. Other applications include the use of emulsions as center-line markers on concrete highways, for surface treatment of bituminous roads,
as damp-proofing or water-proofing media, and as an integral part of the road structure. PETROLEUM GASES
There are yearly available over two-thousand-billion cubic feet of natural gas and three-hundred-billion cubic feet of r e b e r y gases. The former is made up primarily of methane, ethane, and some propane and butanes, while the latter in addition to these components contains ethylene, propylene, and butylenes. These gases are primartly used for fuel purposes. More important uses have developed in recent years, one of which is the liquefaction of propane and butane. Compressed into liquid form, the hydrocarbons are delivered to their destinations in heavy steel bottles, or in tank wagons or tank cars under pressure. Liquefied or "bottled" gases are not alone distributed as fuel for heating and lighting in homes located off the "beaten track"; but they are also useful for industrial purposes, especially where closely controlled temperatures are essential. They have revolutionized gas manufacturing plants which used coal, gas oil, or water-gas reactions to supply the needs of the community. Gas plants have been shut down in some small towns and the liquefied gases, merely mixed with air, are piped to the users. Some gas-making units have also been eliminated, while liquefied gases are added to water gas to give the proper heating value. The heating values of the liquefied hydrocarbons in "bottled gas" are especially notable. Butane has a value of 3200 B.t.u. per cubic foot of gas, and propane contains 2550, both of which contrast forcibly with the usual 550-B.t.u. city gas. That the field for this new "by-product" presents worthy dimensions is aptly shown in the increased production of liquefied gases from about 223,000 gallons in 1922 to approximately 32,000,000 gallons in 1932. Distribution of the product indicates that 17,000,000 gallons were marketed as "bottled gas" for domestic fuel, while 15,000,000 were used as industrial fuel and in city gas. Refmery gases, including not only the "waste" gases from crude-oil distillation but also the vast amounts of gas formed from the cracking process, present a huge potential source of liquefied gases, in addition to that derived from natural gasoline plants and natural gas. It is estimated2 that "the potential supply of liquefied petroleum gases from natural gasoline plants and refineriesis several hundred times greater'than the present demand." P OBERPELL,A . P. I. Proceedings, Section III,15(Dec, 1932).
A further important line of development for refinery gases lie3 in the cracking or reforming of gas having a high B.t.u. content, for the purpose of producing a greater volume of fuel gas having a lower heating value. Reforming may be an independent gascracking process or i t may comprise passing the hydrocarbon gas through an incandescent fuel bed wherein water gas is simultaneously produced. Saturated and unsaturated hydrocarbons, carbon monoxide, and hydrogen, of desirable beat content are obtained. The advent of the cracking process for gasoline production has brought with it a huge supply of highly unsaturated hydrocarbon gases. Gaseous paraffins such as those in natural gas are also being cracked to produce ethylene, propylene, butylene, and butadienes. There are about 45 billion cubic feet per year of ethylene, propylene, butylenes, and butadienes present in all the cracked gases, makmg them highly reactive and valuable for chemical synthesis. Uses to which these olefinic hydrocarbons are adapted include their application as anesthetics, for the ripening of fruits, as raw materials for the production of halogen derivatives, alcohols, acids, ketones, aldehydes, and for polymerization to gasoline, lubricating oil, or resins. Among the most interesting developments in the use of cracked gases is the manufacture of alcohols. The first applications of such gaseous hydrocarbons to alcohol synthesis employed the well-known sulfuric acid process plus hydrolysis. Alcohols of many kinds have been, and are, produced in this way from the different olefins present in cracked gases. The primary, secondary, and tertiary alcohols which have been prepared are both liquids and solids. The most recent, outstanding alcohol synthesis being carried out commercially from cracked gas is the direct union of ethylene and water b y means of catalysts to yield ethyl alcohol. Man's chief competitors, the insects, are being fought with oil, using airplanes to spray it over large areas of insect-infected plant life. Orchards are protected from frost by means of oil or petrgleum coke fires. The temperature surrounding orange groves is controlled to a nicety by the warmth of a wall of petroleum fire. Eggs are embalmed in oil for their preservation, much like the mummies of old with asphalt. Many other uses have been found for oil products and an enormous amount of research work is going on in the oil industry a t yearly costs of millions of dollars to develop new products or find new uses for old products.
One of the feature exhibits of the applied chemistr section at A Century of Progress is a scale model of a complete oil refinery constructed almost entirely of glass. In a c c o d n c e with fire regulations realistically colored solutions are substituted for the various petroleum fractions. The model is supplemented by oil-field and oil-refinery dioramas.
