Composition of Petroleum - American Chemical Society

Composition of Petroleum FREDERICK D. ROSSINI and BEVERIDGE J. MAIR

Downloaded by UNIV OF ARIZONA on December 15, 2012 | http://pubs.acs.org Publication Date: January 1, 1951 | doi: 10.1021/ba-1951-0005.ch029

Carnegie Institute of Technology, Pittsburgh13,Pa.

This paper presents a survey of our present knowledge of the composition of petroleum. Included in the presentation is a brief discussion of the nonhydrocarbon constituents of petroleum, covering sulfur, nitrogen, oxygen, and metallic constituents, together with more detailed information regarding the hydrocarbon constituents which comprise the bulk of crude petroleum. In addition to a discussion of the hydrocarbon compounds and types of hydrocarbon compounds occurring in one representative petroleum, the problem is considered of how different crude petroleums differ in their composition with respect to the hydrocarbon components.

Petroleum is recognized today not only as one of the most important natural resources of the world, but also as one of nature's most interesting and intriguing ones. U n t i l about 1920, investigations on the nature of petroleum and its components were usually of a sporadic and casual nature. About that time, however, the petroleum industry began to be very seriously concerned about the composition of its raw material. Whereas i n the early days petroleum was commercially separated roughly according to molecular size b y the process of simple distillation, the industry desired to produce special products that could better satisfy the more exacting requirements of modern commerce and i n dustry. This could be done, of course, only with reliable information concerning the composition and properties of petroleum and its components. Prior to 1900, the results of work on the composition of petroleum had been published by the following investigators: de L a Rue and M i l l e r (28) i n 1856; Schorlemmer (53) i n 1832; Silliman (56) i n 1871; Engler (12, 18) i n 1879 and 1885; M a b e r y and coworkers (32-85) i n 1895 to 1902; Markownikoff (37-40) i n 1895 to 1900; Y o u n g (62-64) i n 1897 to 1899; Fortey (18,19) i n 1898 and 1899; and Aschan (2) i n 1898. V e r y few significant new investigations were reported between 1900 and 1920. Following 1920, active work was started i n a number of laboratories to begin unraveling the secrets of nature regarding the components of petroleum. I n 1927, the petroleum industry, through the American Petroleum Institute, established A P I Research Project 6 to investigate the composition of petroleum with respect to its hydrocarbon components. This project operated continuously at the National Bureau of Standards i n Washington, D . C . , until June 1950, when i t was moved to the Carnegie Institute of Technology i n Pittsburgh, P a . Concurrently, important related work was carried o n a t the Petroleum Refining Laboratory of the Pennsylvania State College, and i n the laboratories of the U . S. Bureau of Mines. I n the period 1935 to 1940, spectrometric methods of analysis were taken up and developed by the petroleum i n dustry to assist i n the analysis of the complex mixtures being encountered i n petroleum processing. W i t h i n the past ten years, the cooperative work of a number of the American Petroleum Institute Research Projects has provided standard samples for spectrometer 334

In PROGRESS IN PETROLEUM TECHNOLOGY; Advances in Chemistry; American Chemical Society: Washington, DC, 1951.

ROSSINI AND MAIR—COMPOSITION OF PETROLEUM

335

calibration and catalogs of spectral data for guidance i n analytical work. A s a result of these developments, the laboratories of the petroleum industry were i n a position them selves to engage i n fruitful examination of various portions of crude petroleum with re spect to individual components or types of components. The acquisition during the past quarter century of an enormous amount of basic fundamental information on the composition and properties of petroleum and its com ponents has placed the petroleum industry i n a highly competitive and favorable position with regard to the most economical use of its raw material, including the tailor-making of the highly specialized products required by modern industry.


Investigations on Nonhydrocarbon Constituents Sulfur Compounds. A statistical analysis of the sulfur content of crude petro leums of the U n i t e d States, according to their geographical location, has recently been given b y Smith (57). F o r the United States as a whole, nearly 4 0 % of the petroleum currently being produced has a sulfur content of less than 0.25% by weight, while approxi mately 7 % has a sulfur content of more than 2 % b y weight. Substantially all the petroleum production from the Appalachian and Gulf Coast areas of the United States contains less than 0.25% b y weight of sulfur, whereas 3 5 % of the production from the Mississippi area contains more than 2 % b y weight of sulfur. A summary of the work on the identification of sulfur compounds i n crude oils has been given recently b y B a l l , R a i l , Waddington, and Smith (81), who list the sulfur com pounds isolated from petroleum b y earlier investigators and, i n addition, give several new compounds which have recently been isolated from a Wasson, Tex., crude petroleum by the A P I Research Project 48. B i r c h and Norris (5) isolated a substantial number of the thiol (mercaptan) type of sulfur compounds from an Iranian crude petroleum. The sulfur compounds present i n crude petroleum include thiols (mercaptans), openchain sulfides, and cyclic sulfides. B o t h straight and branched-chain thiols and sulfides have been identified. A m o n g the cyclic sulfides, the presence of both thiacyclopentanes and thiacyclohexanes has been established. I n its investigation of the sulfur compounds i n the naphtha fraction of a Wasson, Tex., crude petroleum, A P I Research Project 48 found present i n significant amount a l l but three of the possible sulfur compounds nor mally boiling i n the range 6° to 86° C . The sulfur compounds so identified include six of the thiol type and three of the sulfide type : methanethiol (methyl mercaptan), ethane thiol (ethyl mercaptan), 1-propanethiol (η-propyl mercaptan), 2-propanethiol (isopropyl mercaptan), 2-butanethiol (sec-butyl mercaptan), 2-methyl-2-propanethiol (tert-butyl mercaptan), 2-thiapropane (dimethyl sulfide), 2-thiabutane (methylethyl sulfide), and 3-methyl-2-thiabutane (methylisopropyl sulfide). I n addition to the sulfur compounds listed above, hydrogen sulfide has been found i n many crude petroleums. Elemental sulfur has been definitely found i n several crude petroleums b y A P I Research Project 48 (28). Although Birch and Norris (5) isolated several disulfides from the spent caustic used i n treating gasoline from Iranian petroleum, these compounds may have resulted from the oxidation of the thiols and their presence i n the original petroleum is regarded as doubtful. Other types of sulfur compounds, such as thiophenes and aromatic thiols, have been identified i n cracked petroleum products, but the presence of such compounds i n naturally occurring petroleums has not yet been established. Nitrogen Compounds. S m i t h (57) has recently given a survey of the nitrogen content of crude petroleum from about 150 fields throughout the U n i t e d States. The amount of nitrogen i n these petroleums varies from less than 0.05 to more than 0.5% by weight, with the California petroleums usually having the higher values. Bailey (48) found that certain California petroleums had a nitrogen content as high as 0.8% by weight. Our knowledge of the composition of nitrogen compounds i n petroleum is due largely to the investigations at the University of Texas, including the work of Bailey and co workers from 1928 to 1941, and the more recent work of Lochte and coworkers. These and other pertinent data have been summarized recently by Lochte (30). Approximately half of the nitrogen i n California petroleum is present i n the form of nitrogen bases, and In PROGRESS IN PETROLEUM TECHNOLOGY; Advances in Chemistry; American Chemical Society: Washington, DC, 1951.


336

ADVANCES IN CHEMISTRY SERIES

there have been isolated at the University of Texas a substantial number of quinolines and pyridines with a l k y l substituents, as well as a few pyridines i n which the substituent was a cyclopentyl or cyclohexyl group. I n this latter category are included 3-cyclopentylpyridine, 4-cyclopentylpyridine, and 2,4-dimethyl-6-(2,2,6-trimethylcyclohexyl)pyridine. Recently, a constituent belonging to a different type of base—namely, 2-methylpyridine—was isolated at the University of Texas (80). H a c k m a n , Wibaut, and Gitsels (26) have isolated isoquinoline and 1- and 3-methylisoquinoline, as well as other quinolines, from the bases from a California cracked petroleum stock. I t is not known, however, whether these compounds were present i n the original crude petroleum or resulted from thermal decomposition.. The other nitrogen compounds which are nonbasic, and are not extracted from hydrocarbons b y dilute acid, have not been investigated i n detail, though there are indications that they contain pyrroles. I n addition, i t is possible that some part of the nitrogen i n this material is present i n the form of amides, derived from primary or secondary amines and petroleum acids. O x y g e n Compounds. A c c o r d i n g t o Gruse a n d Stevens (24), the total content of oxygen i n petroleum is generally low, but i n some cases m a y be as high as 2 % b y weight. Some of the oxygen is present i n the form of carboxylic acids and some i n the form of phenols. Lochte (81) has established the presence of acid anhydrides. Esters, alcohols, and ketones may also be present, though the evidence regarding them is not conclusive. Resins and asphaltic materials from petroleum frequently contain considerable amounts of oxygen, although the manner i n which oxygen is combined i n these substances is not known. A s a result of the investigations of Lochte (81), von Braun (7,8), and Nenitzescu (42), and their coworkers, fairly complete information is now available concerning the composition of the carboxylic acids from the lower boiling fractions of petroleum. A summary of this information by Lochte (81) includes references. A substantial number of acids have now been separated and identified, including straight-chain and branched-chain acids as well as acids with cyclopentane or cyclohexane rings i n the molecule. I n the case of the cyclic acids, the carboxyl group may be attached directly to the ring, or through one, two, or possibly three C H groups. V e r y small amounts of aromatic acids have been detected in the acid mixtures from California petroleum. The aliphatic acids isolated from a California crude petroleum b y Lochte and coworkers (81) include: 2-methylpentanoic acid, 3-methylpentanoic acid, n-hexanoic acid, 2-methylhexanoic acid, 3-methylhexanoic acid, 4-methylhexanoic acid, 5-methylhexanoic acid, n-heptanoic acid, n-octanoic acid, and n-nonanoic acid. These investigators found that the normal acids occurred i n much greater abundance than the branched acids. The cyclic acids isolated by Lochte and coworkers (81) include : cyclopentanecarboxylic acid, 2-methylcyclopentanecarboxylic acid, 3-methylcyclopentanecarboxylic acid, cyclopentaneacetic acid, 3-methylcyclopentaneacetic acid, 2,3-dimethylcyclopentaneacetic acid, 1,2,2-trimethylcyclopentanecarboxylic acid, cyclohexanecarboxylic acid, p-methylcyclohexanecarboxylic acid, and the cis and trans forms of 2,2,6-trimethylcyclohexanecarboxylic acid. I n addition, Lochte and coworkers (81) isolated dimethylmaleic anhydride, which has also been isolated by Nenitzescu and coworkers (42). N o t much is known concerning the structure of acids with more than one ring per molecule, though von B r a u n (7, 8) has separated acids with two rings per molecule and has obtained indications that i n some instances these are substituted acetic acids. Goheen (22) separated a mixture of acids from a Gulf Coast petroleum, converted them to the corresponding hydrocarbons, and, b y the methods for hydrocarbon ring analysis, found that they contained on the average 2.6 rings per molecule. Little information is available concerning the composition of phenols from distillates of petroleum, though i n certain instances they may be present i n the acid mixtures i n fairly high concentrations. However, phenol/various alkyl phenols, and cresols have been separated from cracked distillates. M e t a l l i c Constituents. T h e t o t a l ash content of crude petroleum is stated b y Gruse and Stevens (24) to be of the order of 0.01 to 0.05%. Some of the mineral constit2

In PROGRESS IN PETROLEUM TECHNOLOGY; Advances in Chemistry; American Chemical Society: Washington, DC, 1951.



337

uents i n crude petroleum are contained i n solution i n water globules which are finely dis persed i n the oil. Others are, however, soluble i n the oil and may be concentrated into certain fractions by extraction with hydrocarbon and other organic solvents. I n an investigation on a California petroleum, Skinner (66) showed that a reduction i n the amount of the metallic constituents was effected by dehydrating the wet crude i n a high tension alternating electric field. A further reduction was obtained by washing the relatively dry crude produced i n this manner with fresh water and again dehydrating. These two operations removed 8 5 % of the chlorides from the crude petroleum and re duced mineral content b y about one third. Boron, magnesium, silicon, iron, copper, nickel, and vanadium were detected spectrographically in the dry crude petroleum pro duced by these operations, while the original wet crude petroleum contained, i n addition, sodium and strontium. Skinner (56) precipitated an asphaltic portion from the dry Santa M a r i a Valley crude with propane and then extracted the asphaltic portion with a succession of solvents i n the following order: n-pentane, n-hexane, η-heptane, 2,2,4-trimethylpentane, cyclohexane, benzene, and pyridine. Some of the metallic constituents were somewhat soluble i n the propane-oil portion, but a l l tended to be concentrated i n the asphaltic portion. Although vanadium (0.02% by weight i n the original crude petroleum) was present i n all fractions, the greater part was found i n the cyclohexane and benzene fractions. F r o m the similarity of the absorp tion spectra of the vanadium concentrates from petroleum and those of synthetic vana dium porphyrin complexes, Skinner arrived at the conclusion that vanadium compounds from the petroleum of the Santa M a r i a Valley Field i n California exist as porphyrin com plexes. Additional metallic constituents were detected by Skinner as these became con centrated i n the various solvent fractions, including aluminum, titanium, calcium, and molybdenum. Gruse and Stevens (24) list still other metallic constituents which may be present i n recognizable amounts i n the ash from various petroleums, including tellurium, barium, lead, manganese, chromium, and silver. According to these authors, oil-soluble salts of petroleum acids probably account for the small portions of most metallic constituents present i n crude oil.

Investigations on Hydrocarbon Constituents I n the period since 1920, the important investigations dealing with the hydrocarbon components of petroleum have included the following, i n addition to the work of A P I Research Project 6 begun i n 1927: Francis, Watkins, and Waliington (20, 21) i n 1922, relating to normal paraffins (in Scottish shale oil) Chavanne (11) i n 1922, relating to various hydrocarbons present in.the gasoline fraction of a Borneo petroleum Anderson and Erskine (1) i n 1924, relating to propane, η-butane, isobutane, n pentane, isopentane, n-hexane, n-heptane, η-octane, and Ce and C 7 branched paraffins i n a natural gasoline B i r c h and Norris (6) i n 1926, relating to toluene, m-xylene, l-methyl-4-ethylbenzene, 1,2,3-trimethylbenzene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, naphthalene, and two C10 alkylbenzenes i n a Persian petroleum Ferris, Cowles, and Henderson (15,16) i n 1929 and 1931, relating to the waxes i n the lubricant fraction of a mid-continent petroleum Shepard, Henne, and M i d g l e y (54) i n 1931, relating to the η-paraffins, C 5 to C12, i n a Michigan petroleum Fenske, Tongberg, and Quiggle (14, 68) i n 1932 and 1936, relating to 2-methylpentane, r&-heptane, η-octane, methylcyclohexane, and many other compounds of the paraffin, cycioparaffin, and a l k y l benzene types, i n Pennsylvania petroleum M i i l l e r and P i l a t (41) i n 1935, relating to the types of hydrocarbons i n the lubricant fraction Kalvoort, Moser, and Verver (27) i n 1937, relating to petroleum waxes H i c k s - B r u u n , B r u u n , and Fauiconer (26) i n 1939, relating to 2,2-dimethylbutane In PROGRESS IN PETROLEUM TECHNOLOGY; Advances in Chemistry; American Chemical Society: Washington, DC, 1951.



338

Watson and Spinks (61) i n 1940, relating to the composition of the gasoline fraction of a Canadian petroleum Fischer and W e l t y (17) i n 1944, relating to toluene and methyicyclohexane i n 15 different petroleums Gooding, Adams, and R a i l (28) i n 1946, relating to the compounds i n ten different light naphthas W a r d , Gooding, and Eccleston (69) i n 1947, relating to the compounds i n the light gasoline fraction of Oklahoma petroleum B e l l (4) i n 1950, relating to the hydrocarbons i n the light gasoline fraction of East Texas petroleum Zimmerschied, Dinerstein, Weitkamp, and Marschner (65) i n 1950, relating to the normal paraffins, C12 to Cie C a d y , Marschner, and Cropper (9) i n 1951, relating to the composition of the light naphtha fraction of mid-continent petroleum Charlet, Lanneau, and Johnson (10) i n 1951, relating to the types of aromatic compounds i n the gas oil fraction of petroleum Lillard, Jones, and Anderson (29) i n 1951, relating to the types of hydrocarbons i n the lubricating oil fraction of a mid-continent and a Gulf Coast petroleum The work of A P I Research Project 6 has been summarized at various stages i n its progress (86, 44-5% 60) and the current status of the work of this project is summarized i n the following section of the present paper. f

Results Obtained by API Research Project 6 on One Representative Petroleum Problem and General Method of Operation. T h e goal set before A P I Research Project 6 was essentially one of ascertaining the major hydrocarbon constituents of one representative petroleum and then learning how the amounts of the major components vary i n different petroleums. Substantially a l l of the hydrocarbons i n petroleum are composed of paraffin groups, cycloparaffln or naphthene groups, aromatic groups, mixed aromatic-naphthene nuclei, or combinations of these. N o olefin or acetylene hydrocarbons appear to be i n naturally occurring petroleum i n any significant amount. T h e problem is that of separating, without altering the constituents, the complex mixture of hydrocarbons that constitute petroleum, and to obtain the major components i n a substantially pure state. The general method of operation is to utilize the various processes of fractionation i n such combinations as will produce a " s i f t i n g " of the molecules with respect to size on the one hand and to type on the other. T o be successful i n separating a given mixture of hydrocarbons, any process of fractionation must involve a physical property that has significantly different values for the several components of the mixture to be separated. Furthermore, the procedure must be one for which a workable apparatus is available, or for which one can be developed. The standard processes of fractionation used i n this work are distillation, extraction, adsorption, and crystallization, which involve the properties of vapor pressure (or boiling point), solubility, adsorbability, and freezing point (and cryoscopic constant). These processes of fractionation may be used i n several variations: Distillation. A t different pressures; with an added volatile azeotrope-forming substance (for azeotropic distillation) ; with an added relatively nonvolatile selective solvent (for extractive distillation). Extraction. A t different temperatures; with different single solvents; with different multiple solvents. Adsorption. A t different temperatures; with different adsorbents; with the hydrocarbons i n the gas phase; with the hydrocarbons i n the liquid phase; with eluting and diluting liquids; with desorbing liquids. Crystallization. F r o m the mixture of hydrocarbons alone; from a solution of the hydrocarbons i n an appropriate solvent; with centrifuging. I n addition, i t is occasionally possible to use special methods, such as that of separating large ^paraffins through the formation of adducts with urea (65). W i t h regard to the nature of the separation obtained, the foregoing processes of fractionation, excluding crystallization, may be classified according to whether they fracIn PROGRESS IN PETROLEUM TECHNOLOGY; Advances in Chemistry; American Chemical Society: Washington, DC, 1951.



339

tionate primarily with respect to size of molecule or to type of molecule. Separation p r i marily according to size of molecule (or boiling point or molecular weight) is produced b y distillation at one fixed pressure. Separation primarily according to type of molecule is produced by distillation alternately at two fixed pressures, by azeotropic distillation, by extractive distillation, by extraction, and by adsorption. I n connection with separations by type i t is important to note that, except i n certain special cases, alternate distillation at two fixed pressures, distillation with an azeotrope-forming substance, and extractive distillation require a charging stock that is homogeneous with respect to boiling point (or size of molecules)—that is, à relatively narrow boiling charge. O n the other hand, the process of extraction may be used successfully on rather wide boiling charges, and the process of adsorption may be used on extremely wide boiling material. I n connection with separation b y crystallization, two general statements may be made regarding hydrocarbons: F o r a given degree of symmetry of the molecule the freezing point usually is higher the greater the size of the molecule; for a given number of carbon atoms i n the molecule, the freezing point usually is higher the greater the s y m metry of the molecule. Except for those few hydrocarbons i n the volatile range that have boiling points relatively far from their neighbors, and for certain other hydrocarbons present i n relatively large amount (as η-paraffins i n a Pennsylvania or a M i c h i g a n petroleum), regular distil lation alone will not separate pure hydrocarbons from petroleum, and one or more of the other methods (including the variations of distillation) must also be used. The order i n which the several methods are used is determined by the effectiveness of a given process i n increasing the separation attained by the preceding method. Thus, although a given process may be ineffective when used alone, its systematic use i n appro priate combination with other processes can often lead to the complete separation of an otherwise unseparable constituent. Identification a n d P u r i t y of Single Substances. Before attempting to identify a material separated from petroleum as a given compound b y comparison of its proper ties w i t h those of k n o w n pure compounds, i t is necessary to prove t h a t the material is substantially a single substance and not a mixture. If a logical sequence of fractionat ing processes, including distillation at high efficiency, has been followed, the given material will consist of molecules of the same size and type—that is, a mixture of isomers. I n some cases, one of the isomers will constitute the bulk of the material, which may then be considered substantially one compound. I n deciding upon the property which is to be used i n establishing the fact that the material is or is not substantially one compound, consideration must be given t o the following facts: The material is substantially constant-boiling as a result of its having been produced by a sequence of fractionating processes involving high-efficiency distillation. Therefore, examination of the boiling point as a function of the percentage of the sample vaporized or condensed will be of little or no value i n this connection. The minor components present with the major component will normally be isomers of the latter, as a result of the material's having been well fractionated b y type of mole cule. The isomers will have values of the density, refractive index, and similar properties, very nearly the same as those of the major component, so that these properties will be of little or no value i n this connection. Furthermore, such isomeric minor components will constitute the very compounds which will be most likely to form with the major com ponent a substantially ideal solution. One of the most effective methods for evaluating the purity of chemical substances is that involving determination of the freezing point, with appropriate observation of the temperature of the liquid-solid equilibrium as a function of the fraction of sample frozen or melted. I n the absence of information as to the identity of the impurities or minor components associated with the parent substance, or of the identity of parent substance as well as the impurities, i t appears that the freezing point is the only property which may be utilized to give a quantitative estimate of the purity. In PROGRESS IN PETROLEUM TECHNOLOGY; Advances in Chemistry; American Chemical Society: Washington, DC, 1951.

340



Whenever the identities of the major component and of its impurities are known, the amounts of the major and minor components can be satisfactorily determined by means of spectrometric measurements (infrared, ultraviolet, Raman, or mass, as appropriate), provided pure standard samples of the major component and each of the minor components are available for calibration of the given spectrometer. I n the problem of identifying and determining the purity of individual hydrocarbons separated from petroleum, the following cases occur, i n order, as knowledge of the material being investigated increases. A t first, no information is available as t o the chemical* constitution of the material except a knowledge of the elements which compose i t . I n this case, the investigation may proceed as follows: T h e fact that the material separated is substantially a single substance and not a mixture is established. T h i s may be done, as described before, by suitable observations of the temperature of the liquid-solid equilibrium as a function of the fraction of the sample frozen or melted. Such observations also serve to determine, within appropriate limits, the amount of impurity i n the given sample. B y measurements of elemental composition and molecular weight, the molecular formula of the substance is determined. Measurements are made of the simple physical properties of the freezing point (this property will usually already have been measured i n the determination of purity), boiling point, density, and refractive index. T h e foregoing properties are necessary. T h e following properties may also be determined i f equipment is available : viscosity, solubility i n a proper solvent, and critical solution temperature i n a proper solvent. The simple physical properties of the given substance are compared with the same properties of known pure compounds of the same molecular formula. If adequate matching can be made of the freezing point, refractive index, and density of the given substance with a known pure compound of the same molecular formula, the identification may be considered substantially complete. If, however, the identification just outlined cannot be made, i t will appear that the given substance is not identical with any known compound of the same molecular formula and, to complete the identification, further steps must be taken : Measurement is made of the spectrographic properties, including infrared absorption and ultraviolet absorption. The R a m a n spectra and mass spectrometer pattern may also be determined. B y analysis and comparison of the physical and spectrographic properties of the u n known substance with those of known compounds of the same molecular formula, i t will be possible to establish the identity of the group of isomeric compounds to which the u n known substance belongs. I t should be possible also to establish the several most probable compounds with which the unknown may possibly be identified. Arrangements are made for the synthesis of the most probable compounds i n turn until one is prepared, the properties of which match those of the substance separated from petroleum sufficiently well to establish the identity. After sufficient information has been obtained as to the types of components which constitute a given fraction or boiling range of petroleum, subsequent examination of such material can be greatly simplified b y the elimination of certain steps. I n most cases, for example, i t becomes unnecessary to make an elemental analysis or determine the molecular weight. Whenever a l l the possible components present i n significant amount i n any given fraction of petroleum are known, and when reliable values are available for the simple physical properties of pure samples of the possible components, the identification of a substance separated from the given fraction becomes a relatively simple matter. I n such case, the procedure would be to establish the fact that the material separated is substantially a single substance, measure its simple physical properties, and match these physical properties with those of one of the possible components. I n many cases, spectrographic identification can be made more readily than identification b y measurement of the simple physical properties. Characterization of Homogeneous M i x t u r e s of Hydrocarbons. I n the higher boiling fractions of petroleum, such as the gas oil and lubricant portions, the isolation In PROGRESS IN PETROLEUM TECHNOLOGY; Advances in Chemistry; American Chemical Society: Washington, DC, 1951.



Table I.

341

Hydrocarbons Isolated from One Representative Petroleum from the Ponca, Okla., Field

Formula

Compound

Type*

Boiling Point at 1 Atm., C.

CHi C«He CeHe C4H10 C4H10 CeHu CeHu C»Hio CeHu CêHu CeHu CeHi4 CeHi4 CéHis CîHie CeHe C7HH CiHit C7H14

Methane Ethane Propane Isobutane n-Butane 2-Methylbutane n-Pentane Cyclopentane 2,2-Dimethylbutane 2,3-Dimethylbutane 2-Methylpentane 3-Methylpentane n-Hexane Methylcyclopentane 2,2-Dimethylpentane Benzene 2,4-Dimethylpentane Cyclohexane 1,1-Di methylcyclopentane 2,3-Dimethylpentane 2-Methylhexane f l,irane-3-Dimethylcyclopentane l,cis-3-Dimethylcyclopentane 3-Methylhexane l.irane-2-Dimethylcyclopentane 3-Ethylpentane n-Heptane Methylcyclohexane Ethvlcvclopentane 1,1,3-Trimethylcyclopentane 2,2-Dimethylhexane 2,5-Dimethylhexane l,irana-2,c»s-4-Trimethylcyclopentane 2,4-Dimethylhexane 2,2,3-Trimethylpentane l,

Composition of Petroleum - American Chemical Society

Recommend Documents