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Composition and distribution of aliphatic acids and hydrocarbons on Kyurovdag crude oil
Petrol. Chem. U.S.S.R. Vol, 25, No. 3, pp. 139-144, 1985 Printed in Poland
0031-6458/85 $10.00+.00 © Pergamon Journals Ltd.
COMPOSITION rAND DISTRIBUTION OF ALIPHATIC ACIDS AND HYDROCARBONS ON KYUROVDAG CRUDE OIL* L. P. KOLESNIKOVA,T. G. BOIKOVAand G. V. 1V[OROZOVA I. M. Gubkin Institute of Petrochemical and Gas Industry, Moscow (Received 1 October 1984)
IN SPITE of their extensive practical application [1], carboxylic acids are among the relatively little known oil components. These compounds also provide valuable information regarding special features of the formation and origin of oils. The genetic affinity between acids and petroleum hydrocarbons is highlighted and confirmed by study of the thermocatalytic transformations of fatty acids under laboratory conditions [2, 3]. It is interesting to observe possible correlation between individual and group composition of hydrocarbons and acids in individual crude oils. Such correlations have only been studied in Soviet crude oil for lower carboxylic acids and the hydrocarbons of gasoline fractions from West Siberian crude oil [4]. This paper investigates the composition of aliphatic hydrocarbons and crude oil acids of Kyur,ovdag (Azerbaidzhan S.S.R.). EXPERIMENTAL
Crude oil acids were extracted at the Baku Oil Refinery and recovered after treatment of the salts with mineral acids (GOST-13302-77). A fraction b.p. 170°-350°C was subsequently isolated from the initial crude oil acid mixture; this fraction was refined by saponification [5] of the acids concentrate followed by the recovery of unsaponifiables with light petroleum spirit and liberation of the organic acids by mineral acids. The yield of petroleum acids was 98 wt. %. The refined acids contained 0.3 % wt. of unsaponifiable compounds (determined by the benzene method [6]). The petroleum acids showed the following physico-chemical characteristics: f2o 20 /'/D Acid number (rag KOH/g) Molar mass (according to the acid number) Unsaponifiable (wt. ~) before refining after refining * Neftekhimiya 25, No. 4, 447--451, 1985. 139
0.9780 1-4720 254 221 1"7 0"3
140
L.P. KOLESNIKOVAet al.
The following hydrocarbons were synthesized from the acids obtained using the N. D. Zelinskii system: RCOOH~ RCOOR'~RCH2OH-~ RCHBr~ RCH3, where R' is the methyl radical. This method is widely used for the study of the composition of petroleum acids [7-9]. The petroleum hydrocarbons and the hydrocarbons obtained from the acids were dearomatized by liquid adsorption chromatography. Dearomatized fractions were examined by mass-spectrometric analysis and capillary gas-liquid chromatography [7, 10]. Thermal diffusion and G.L.C. were used [7] to determine the composition of the aliphatic hydrocarbons derived from petroleum acids and, characterized by high naphthene content. Chromatographic analysis conditions were as follows: linear temperature programming (from 100°C at 2 deg/min) using a capillary column (50 m x0.25 ram) coated with Apiezone L; helium was the carrier-gas and a flame-ionization detector was used. Chromatographic peaks were identified using standard n-alkanes and literature data [11]. Quantitative n-paraffin contents of the fractions were determined by urea adduction. RESULTS
The hydrocarbons obtained from petroleum acids contained fewer aromatic components (6.5 wt. ~) than did the hydrocarbon isolated directly from petroleum (25 wt. ~). The mass-spectrometric data (Table 1) indicate that the dearomatized fraction of petroleum hydrocarbons contained 65.1 w t . ~ naphthenes, while the hydrocarbons synthesized from petroleum acids contained some 87.7 wt. ~ of bicyclic structures. The current work defines the individual composition and distribution of aliphatic hydrocarbons, those present in petroleum as well as those formed from petroleum acids; they include: normal, and monomethylsubstituted and isoprenoid alkanes, the latter show natural product association. Acids and hydrocarbons of normal strcuture, n-Paraffins (Clo-C20) some 9.4 wt. ~ were identified in the fractions ar_a!ysed whilst Clo-Czs n-alkanes (5.3 wt. ~) were contained in those synthesized from petroleum acids. The data (Table 2) indicate that the natural normal aliphatic structures in petroleum are characterized by paraffins in the carbon number range C,,-Cls (79.0 wt. ~), whilst most of petroleum fatty acids occur in the carbon number range C13-C16 (74-2 wt. ~o). Myriztic (C~4), palmitic (Ca6) and stearic (C~8) acids predominate among petroleum acids but a significant amount of dodecanoic ~[nd pentadecanoic acids were also found. The ratio of (C~6 + C18)/2C27is accepted as the measure of relative concentration of even: odd paraffins in petroleum [13]. For the petroleum hydrocarbons examined this ratio is 1.0, while for fatty acids it is 1-2. In the petroleum studied which is of the
Composition and distribution of aliphatic acids and hydrocarbons
TABLE I.
G R O U P COMPOSITION OF SATURATED HYDROCARBONS
Hydrocarbons From petroleum From petroleum acids
I Paraffins [ ] [
34-9 12-3
mono31-2 32.5
141
(wt.~) [I0]
Naphthenes bitri18.0 11"5 43.2 10-5
tetra4.4 1.5
Pliocene period concentrations of odd and even normal structures are equalized both in the petroleum hydrocarbons and in acids. The existence in petroleums of normal fatty acids, no doubt, is related to the formation of the hydrocarbons contained in petroleum, confirmed by the similarity of structures. lsoprenane structures. Isoprenane hydrocarbons called "biological tracers" are among petroleum hydrocarbons that have been studied in most detail [8, 11]. However, only a few studies [7, 8] investigate the composition of isoprenanoic acids in Soviet petroleums. Isoprenane hydrocarbons C12-C2o (14"2 w t . ~ per fraction) were contained in the fraction (170°-350°C). Isoprenanes with the same number of carbon atoms per molecule (2.8 wt. ~ per fraction)were identified in a hydrocarbon fraction obtained from the petroleum acids. Investigation of the hydrocarbons from the petroleum acids point to the presence of isoprenane structures with methyl substituents both in positions 2,6-; 2,6,10-; 2,6,10,14- and in positions 3,7-; 3,7,11-. These isprenane structures obsei'ved in petroleum acids, are typical of hydrocarbons contained in the petroleum. The data (Table 2) indicate that the composition of hydrocarbons in petroleum as well as those hydrocarbons obtained from petroleum acids are predominantly isoprenoid: 2,6,10-trimethylundecane, 2,6,10-trimethyldodecane~ 2,6,10-trimethyltridecane, 2,6,10,14-tetramethylpentadecane (pristane) and 2,6,10,14-tetramethylhexadecane (phytane). However a marked difference is observed in the relative distribution of structures with methyl substituents in positions 3,7- and 3,7,11-isolated from petroleum and from petroleum acids. The literature gives no indication of the source of isoprenane acids, which could give 2,6,10-trimethyltetradecane on reduction. Eglinton [14] assumes the presence of 5,9,13-trimethyltetradecanoic acid, formed during gradual decomposition of dihydrophytol. This may explain the appreciable concentration of the C17 isoprenanc in hydrocarbons obtained from petroleum acids. This alkane present in petroleum only in low concentration is not derived from the breakdown of phytol thermocatalytically [11]. According to the methods used, the isoprenane hydrocarbon, 3,7,11-trimethyltridecane may be formed from 3,7,10-trimethyltridecanoic acid, the only acid corresponding to this hydrocarbon. We first found this acid in petroleum. The literature gives no information about the content of 3,7dimethyldodecanoic acid in petroleum, however the current work indicates the presence of this acid since the hydrocarbon of corresponding composition and struc-
142
L.P. KOLESNIKOVAet al. (a), HYDROb.p. 170°-350°C FROM
TABLE 2. DISTRIBUTION (Wt. ~o ]PER TOTAL OF ISOMERS) OF PETROLEUM HYDROCARBONS CARBONS DERIVED FROM PETROLEUM ACIDS
(b)
IN A PETROLEUM FRACTION
KYUROVDAG
Hydrocarbon Decane Undecane Dodecane Tridecane Tetradecane Pentadecane Hexadecane Heptadecane Octadecane Nonadecane Eicosane 2,6-Dimethyldecane 3,7-Dimethyldecane 2,6-Dimethylundecane 2,6,10-Trimethylundecane 2-Methyldecane 3.Methyldecane 5-Methylundecane 4-Methylundecane 2-Methylundecane 3-Methylundecane 5-Methyldodecane 4.Methyldodecane 3-Methyldodecane 7-Methyltridecane 6-Methyltridecane 5-Methyltridecane 4-Methyltridecane
a 0"9 2"2 5.6 7.2 11.3 15.8
b 1"0 4"5 7"2 13"1 26"2 19'9
Hydrocarbon 2-Methyltridecane 3-Methyltridecane 5-Methyltetradecane 4-Methyltetradecane 2-Methyltetradecane 5-Methylpentadecane 4-Methylpentadecane 2-Methylpentadecane 3-Methylpentadecane 2,6-Dimethyldodecane 3,7-Dimethyldodecane 2,6,10-Trimethyldodecane 2,6,10-Trimethyltridecane 3,7,11-Trimethyltridecane 2,6,10-Trimethyltetradecane 2,6,10-Trimethylpentadecane 2,6,10,14-Tetramethylpentadecane (pristane) 2,6,10-Trimethylhexadecane 2,6,10,14-Tetramethylhexadecane (phytane) 2,6,10,14-Tetramethylheptadecane 2-Methylhexadecane 3-Methylhexadecane 2-Methylheptadecane 3-Methylheptadecane
a
b w
11.2 6"5 8'9 3.1 3.7 5"0 32"2 8.5 19"2 6"6 1"8 7"4 9'2 1"4 100 4"6 2.3 4"8 2.3 100
100
100
ture was found. The ratio of the pristane to phytane acid content is 0-8. The low concentrations of pristane acid, (compared with phytane acid) has also been observed in other petroleums [7]. Hydrocarbons of the petroleum examined are characterized by the predominance of pristane over phytane and the pristane : phytane ratio is such that it is considered to be a genetic indicator for this type of petroleum (2.3). Monomethyl-substituted hydrocarbons and acids. Monomethyl-substituted hydrocarbons are among the most significant iso-paraffins in petroleums, their maximum proportion is normally represented by 2- and 3-methylparaffins, i.e. structures, which relate directly to the carbon skeletons of iso- and ante-isoacids. Aliphatic monomethyl-substituted acids Clo-C2o, are among the petroleum compounds that have been little examined in this country. The data (Table 2) indicate that in the hydrooarbons from acids and those from the petroleum fraction studied, the main proporlion of monomethyl-substituted paraffins has a structure with methyl substituents
Composition and distribution of aliphatic acids and hydrocarbons
143
in positions 2- and 3- (69.3 ~ in the hydrocarbons from acids and 67.6 ~ = in the petroleum hydrocarbons). Petroleum hydrocarbons contain a larger proportion cf 2-methylparztiins (38.1 ~o), 29"5?/oo is due to 3-methylparaffins Hydrocarbons derived from petrok~+m z~cids contain a large prcpcrtion of 3methyl-substituted structures (42-1 ~), whilst the content of 2-methylparaffins is 27.2~. Among the petroleum hydrocarbons, monomethyl-substitmed structures with substituents in positions 5-, 6-, 7- are seen only in negligible concentrations, while in the hydrocarbons obtained from petrck~+m acids these isomers have not been observed. SUMMARY
1. The composition of aliphatic acids and hydrocarbons in Kyurovdag crude oil (fractions b.p. 170°-350°C) was examined. These crude oil acids were converted (via ester, alcohol and halide derivative to the corresponding hydrocarbons), the latter revealed the structure of the crude oil acids. 2. A marked similarity was noted between the composition and distribution of the crude oil hydrocarbons and those synthesized from petroleum acids. However, the isoprenane hydrocarbons from petroleum acids contained more structures with methyl substituents at 3,7- and 3,7,11- than did the petroleum hydrocarbons. 2- and 3-Methylalkanes dominate the monomethyl alkanes in both the petroleum hydrocarbons and those from petroleum acids. 3. 3,7,11-trimethyltridecanoic and 3,7-dimethyldodecanoic acids were found for the first time in petroleum. REFERENCES
I. N. S. NAMETKIN, G. M. YEGOROVA and V. Kh. KHAMAYEV, Naflenovyye kisloty i produkty ikh khimicheskoi pererabotki (Naphthenic Acids and Products of Chemical Conversion), p. 11, Khimiya, Moscow, 1982 2. P . L . PARKER, Zhirnyye kisloty i spirty. Organicheskaya geokhimiya (Fatty Acids and Alcohols. Organic Geochemistry), (Ed. G. Eglinton, T. M. G. Murphy) p. 255, Nedra, 1974 3. Yu. A. BEDOV, S. D. PUSTIL'NIKOVA, R. V. RATNIKOVA and A. A. PETROV, Neftekhimiya 2, 3, 313, 1962 4. S. V. CHERNYAVSKAYA, T. A. FILIMONOVA, V. F. KAM'YANOV, /qeftekhimiya 23, 1, 130, 1983 5. B. M. RYBAK, Analiz nefti i nefteproduktov (Analysis of Petroleum and Oil Products), p. 780, Gostoptekhizdat, Moscow, 1962 6. A. M. KULIYEV, R. Sh. KULIYEV and K. I. ANTONOVA, Naftenovy~ce kisloty (Naphthenic Acids), p. 97, Khimiya, Moscow, 1965 7. N. S. NAMETKIN, L. P. KOLESNIKOVA, T. G. BAIKOVA, A. A. BOBYLEVA, L. K. RUMYANTSEVA and G. V. MOROZOVA, Neftekhimiya 19, 1, 127, 1979 8. R. V. ANBROKH, V. A. GARBALINSKII, A. V. BOGATSKII, Al. A. PETROV and M. L KRASAVCHENKO, Khimiya i tekhnologiya topliv i masel, 8, I1, 1972
144
R.N. VOLKOVet aL
9. J. KNOTERUS J. Inst. Petrol. 43, 307, 1957 10. A. A. POLYAKOVA, Molekularnyi mass-spektral'nyi analiz neftei, p. 130, Nedra, Moscow, 1973 11. AI. A. PETROV, Khimiya alkanov, pp. 204, 213, Nauka, Moscow, 1974 12. N. B. VASSOYEVICH, A. N. GUSEVA and I. E. LEIFMAN, Geokhimiya, 7, 1075, 1976 13. G. BREI and G. EVANS, Uglevodorody v materinskikh ottozheniyakh. Symp.: Organicheskaya geokhimiya, pp. 2, 93, Nedra, Moscow, 1970 14. G. EGLINTON, Organicheskaya geokhimiya (Ed. G. Eglinton and T. M. G. Murphy) p. 29, Nedra, Leningrad, 1974
Petrol. Chem. U.S.S.R. Vol. 25, No. 3, pp. 1'44-148, 1985 Printed in Poland
0031-6458/85 $10.00 + .00 © Pergamon Journals Ltd.
OXIDATIVE DEHYDROGENATION OF ETHYLBENZENE ON VANADIUM-MAGNESIUM OXIDE CATALYSTS* R. N. VOLKOV, V. P. PANOVA, I. P. BELOMESTNYKI-I,G. V. SHAKHNOVICHand
~. V. ISAGULYANTS N. D. Zelinskii Institute of Organic Chemistry, U.S.S.R. Academy of Sciences Voronezh Branch of the S. V. Lebedev All-Union Scientific Research Institute of Synthetic Rubber Manufacture (Received 2 January 1984)
PREVIOUS studies [1, 2] showed that vanadium-magnesium oxide catalysts are highly active and selective for the oxidative dehydrogenation of ethylbenzene to styrene. The present work investigates catalyst stability under conditions of continuous operation without recovery. EXPERIMENTAL
Oxidative dehydrogenation was carried out in an adiabatic reactor consisting of five sections (50 x 1850 mm), each section carried an electrically heated lining, a thermocouple and connecting pipes for the supply of air, steam and for sampling; the first section was filled with Raschig rings and served as a mixer. The vanadium-magnesium oxide catalyst prepared by mixing a m m o n i u m metavanadate or vanadium pent0xide, modifying components and magnesium oxide, * Neftekhimiya 25, No. 4, 468--471, 1985.
0031-6458/85 $10.00+.00 © Pergamon Journals Ltd.
COMPOSITION rAND DISTRIBUTION OF ALIPHATIC ACIDS AND HYDROCARBONS ON KYUROVDAG CRUDE OIL* L. P. KOLESNIKOVA,T. G. BOIKOVAand G. V. 1V[OROZOVA I. M. Gubkin Institute of Petrochemical and Gas Industry, Moscow (Received 1 October 1984)
IN SPITE of their extensive practical application [1], carboxylic acids are among the relatively little known oil components. These compounds also provide valuable information regarding special features of the formation and origin of oils. The genetic affinity between acids and petroleum hydrocarbons is highlighted and confirmed by study of the thermocatalytic transformations of fatty acids under laboratory conditions [2, 3]. It is interesting to observe possible correlation between individual and group composition of hydrocarbons and acids in individual crude oils. Such correlations have only been studied in Soviet crude oil for lower carboxylic acids and the hydrocarbons of gasoline fractions from West Siberian crude oil [4]. This paper investigates the composition of aliphatic hydrocarbons and crude oil acids of Kyur,ovdag (Azerbaidzhan S.S.R.). EXPERIMENTAL
Crude oil acids were extracted at the Baku Oil Refinery and recovered after treatment of the salts with mineral acids (GOST-13302-77). A fraction b.p. 170°-350°C was subsequently isolated from the initial crude oil acid mixture; this fraction was refined by saponification [5] of the acids concentrate followed by the recovery of unsaponifiables with light petroleum spirit and liberation of the organic acids by mineral acids. The yield of petroleum acids was 98 wt. %. The refined acids contained 0.3 % wt. of unsaponifiable compounds (determined by the benzene method [6]). The petroleum acids showed the following physico-chemical characteristics: f2o 20 /'/D Acid number (rag KOH/g) Molar mass (according to the acid number) Unsaponifiable (wt. ~) before refining after refining * Neftekhimiya 25, No. 4, 447--451, 1985. 139
0.9780 1-4720 254 221 1"7 0"3
140
L.P. KOLESNIKOVAet al.
The following hydrocarbons were synthesized from the acids obtained using the N. D. Zelinskii system: RCOOH~ RCOOR'~RCH2OH-~ RCHBr~ RCH3, where R' is the methyl radical. This method is widely used for the study of the composition of petroleum acids [7-9]. The petroleum hydrocarbons and the hydrocarbons obtained from the acids were dearomatized by liquid adsorption chromatography. Dearomatized fractions were examined by mass-spectrometric analysis and capillary gas-liquid chromatography [7, 10]. Thermal diffusion and G.L.C. were used [7] to determine the composition of the aliphatic hydrocarbons derived from petroleum acids and, characterized by high naphthene content. Chromatographic analysis conditions were as follows: linear temperature programming (from 100°C at 2 deg/min) using a capillary column (50 m x0.25 ram) coated with Apiezone L; helium was the carrier-gas and a flame-ionization detector was used. Chromatographic peaks were identified using standard n-alkanes and literature data [11]. Quantitative n-paraffin contents of the fractions were determined by urea adduction. RESULTS
The hydrocarbons obtained from petroleum acids contained fewer aromatic components (6.5 wt. ~) than did the hydrocarbon isolated directly from petroleum (25 wt. ~). The mass-spectrometric data (Table 1) indicate that the dearomatized fraction of petroleum hydrocarbons contained 65.1 w t . ~ naphthenes, while the hydrocarbons synthesized from petroleum acids contained some 87.7 wt. ~ of bicyclic structures. The current work defines the individual composition and distribution of aliphatic hydrocarbons, those present in petroleum as well as those formed from petroleum acids; they include: normal, and monomethylsubstituted and isoprenoid alkanes, the latter show natural product association. Acids and hydrocarbons of normal strcuture, n-Paraffins (Clo-C20) some 9.4 wt. ~ were identified in the fractions ar_a!ysed whilst Clo-Czs n-alkanes (5.3 wt. ~) were contained in those synthesized from petroleum acids. The data (Table 2) indicate that the natural normal aliphatic structures in petroleum are characterized by paraffins in the carbon number range C,,-Cls (79.0 wt. ~), whilst most of petroleum fatty acids occur in the carbon number range C13-C16 (74-2 wt. ~o). Myriztic (C~4), palmitic (Ca6) and stearic (C~8) acids predominate among petroleum acids but a significant amount of dodecanoic ~[nd pentadecanoic acids were also found. The ratio of (C~6 + C18)/2C27is accepted as the measure of relative concentration of even: odd paraffins in petroleum [13]. For the petroleum hydrocarbons examined this ratio is 1.0, while for fatty acids it is 1-2. In the petroleum studied which is of the
Composition and distribution of aliphatic acids and hydrocarbons
TABLE I.
G R O U P COMPOSITION OF SATURATED HYDROCARBONS
Hydrocarbons From petroleum From petroleum acids
I Paraffins [ ] [
34-9 12-3
mono31-2 32.5
141
(wt.~) [I0]
Naphthenes bitri18.0 11"5 43.2 10-5
tetra4.4 1.5
Pliocene period concentrations of odd and even normal structures are equalized both in the petroleum hydrocarbons and in acids. The existence in petroleums of normal fatty acids, no doubt, is related to the formation of the hydrocarbons contained in petroleum, confirmed by the similarity of structures. lsoprenane structures. Isoprenane hydrocarbons called "biological tracers" are among petroleum hydrocarbons that have been studied in most detail [8, 11]. However, only a few studies [7, 8] investigate the composition of isoprenanoic acids in Soviet petroleums. Isoprenane hydrocarbons C12-C2o (14"2 w t . ~ per fraction) were contained in the fraction (170°-350°C). Isoprenanes with the same number of carbon atoms per molecule (2.8 wt. ~ per fraction)were identified in a hydrocarbon fraction obtained from the petroleum acids. Investigation of the hydrocarbons from the petroleum acids point to the presence of isoprenane structures with methyl substituents both in positions 2,6-; 2,6,10-; 2,6,10,14- and in positions 3,7-; 3,7,11-. These isprenane structures obsei'ved in petroleum acids, are typical of hydrocarbons contained in the petroleum. The data (Table 2) indicate that the composition of hydrocarbons in petroleum as well as those hydrocarbons obtained from petroleum acids are predominantly isoprenoid: 2,6,10-trimethylundecane, 2,6,10-trimethyldodecane~ 2,6,10-trimethyltridecane, 2,6,10,14-tetramethylpentadecane (pristane) and 2,6,10,14-tetramethylhexadecane (phytane). However a marked difference is observed in the relative distribution of structures with methyl substituents in positions 3,7- and 3,7,11-isolated from petroleum and from petroleum acids. The literature gives no indication of the source of isoprenane acids, which could give 2,6,10-trimethyltetradecane on reduction. Eglinton [14] assumes the presence of 5,9,13-trimethyltetradecanoic acid, formed during gradual decomposition of dihydrophytol. This may explain the appreciable concentration of the C17 isoprenanc in hydrocarbons obtained from petroleum acids. This alkane present in petroleum only in low concentration is not derived from the breakdown of phytol thermocatalytically [11]. According to the methods used, the isoprenane hydrocarbon, 3,7,11-trimethyltridecane may be formed from 3,7,10-trimethyltridecanoic acid, the only acid corresponding to this hydrocarbon. We first found this acid in petroleum. The literature gives no information about the content of 3,7dimethyldodecanoic acid in petroleum, however the current work indicates the presence of this acid since the hydrocarbon of corresponding composition and struc-
142
L.P. KOLESNIKOVAet al. (a), HYDROb.p. 170°-350°C FROM
TABLE 2. DISTRIBUTION (Wt. ~o ]PER TOTAL OF ISOMERS) OF PETROLEUM HYDROCARBONS CARBONS DERIVED FROM PETROLEUM ACIDS
(b)
IN A PETROLEUM FRACTION
KYUROVDAG
Hydrocarbon Decane Undecane Dodecane Tridecane Tetradecane Pentadecane Hexadecane Heptadecane Octadecane Nonadecane Eicosane 2,6-Dimethyldecane 3,7-Dimethyldecane 2,6-Dimethylundecane 2,6,10-Trimethylundecane 2-Methyldecane 3.Methyldecane 5-Methylundecane 4-Methylundecane 2-Methylundecane 3-Methylundecane 5-Methyldodecane 4.Methyldodecane 3-Methyldodecane 7-Methyltridecane 6-Methyltridecane 5-Methyltridecane 4-Methyltridecane
a 0"9 2"2 5.6 7.2 11.3 15.8
b 1"0 4"5 7"2 13"1 26"2 19'9
Hydrocarbon 2-Methyltridecane 3-Methyltridecane 5-Methyltetradecane 4-Methyltetradecane 2-Methyltetradecane 5-Methylpentadecane 4-Methylpentadecane 2-Methylpentadecane 3-Methylpentadecane 2,6-Dimethyldodecane 3,7-Dimethyldodecane 2,6,10-Trimethyldodecane 2,6,10-Trimethyltridecane 3,7,11-Trimethyltridecane 2,6,10-Trimethyltetradecane 2,6,10-Trimethylpentadecane 2,6,10,14-Tetramethylpentadecane (pristane) 2,6,10-Trimethylhexadecane 2,6,10,14-Tetramethylhexadecane (phytane) 2,6,10,14-Tetramethylheptadecane 2-Methylhexadecane 3-Methylhexadecane 2-Methylheptadecane 3-Methylheptadecane
a
b w
11.2 6"5 8'9 3.1 3.7 5"0 32"2 8.5 19"2 6"6 1"8 7"4 9'2 1"4 100 4"6 2.3 4"8 2.3 100
100
100
ture was found. The ratio of the pristane to phytane acid content is 0-8. The low concentrations of pristane acid, (compared with phytane acid) has also been observed in other petroleums [7]. Hydrocarbons of the petroleum examined are characterized by the predominance of pristane over phytane and the pristane : phytane ratio is such that it is considered to be a genetic indicator for this type of petroleum (2.3). Monomethyl-substituted hydrocarbons and acids. Monomethyl-substituted hydrocarbons are among the most significant iso-paraffins in petroleums, their maximum proportion is normally represented by 2- and 3-methylparaffins, i.e. structures, which relate directly to the carbon skeletons of iso- and ante-isoacids. Aliphatic monomethyl-substituted acids Clo-C2o, are among the petroleum compounds that have been little examined in this country. The data (Table 2) indicate that in the hydrooarbons from acids and those from the petroleum fraction studied, the main proporlion of monomethyl-substituted paraffins has a structure with methyl substituents
Composition and distribution of aliphatic acids and hydrocarbons
143
in positions 2- and 3- (69.3 ~ in the hydrocarbons from acids and 67.6 ~ = in the petroleum hydrocarbons). Petroleum hydrocarbons contain a larger proportion cf 2-methylparztiins (38.1 ~o), 29"5?/oo is due to 3-methylparaffins Hydrocarbons derived from petrok~+m z~cids contain a large prcpcrtion of 3methyl-substituted structures (42-1 ~), whilst the content of 2-methylparaffins is 27.2~. Among the petroleum hydrocarbons, monomethyl-substitmed structures with substituents in positions 5-, 6-, 7- are seen only in negligible concentrations, while in the hydrocarbons obtained from petrck~+m acids these isomers have not been observed. SUMMARY
1. The composition of aliphatic acids and hydrocarbons in Kyurovdag crude oil (fractions b.p. 170°-350°C) was examined. These crude oil acids were converted (via ester, alcohol and halide derivative to the corresponding hydrocarbons), the latter revealed the structure of the crude oil acids. 2. A marked similarity was noted between the composition and distribution of the crude oil hydrocarbons and those synthesized from petroleum acids. However, the isoprenane hydrocarbons from petroleum acids contained more structures with methyl substituents at 3,7- and 3,7,11- than did the petroleum hydrocarbons. 2- and 3-Methylalkanes dominate the monomethyl alkanes in both the petroleum hydrocarbons and those from petroleum acids. 3. 3,7,11-trimethyltridecanoic and 3,7-dimethyldodecanoic acids were found for the first time in petroleum. REFERENCES
I. N. S. NAMETKIN, G. M. YEGOROVA and V. Kh. KHAMAYEV, Naflenovyye kisloty i produkty ikh khimicheskoi pererabotki (Naphthenic Acids and Products of Chemical Conversion), p. 11, Khimiya, Moscow, 1982 2. P . L . PARKER, Zhirnyye kisloty i spirty. Organicheskaya geokhimiya (Fatty Acids and Alcohols. Organic Geochemistry), (Ed. G. Eglinton, T. M. G. Murphy) p. 255, Nedra, 1974 3. Yu. A. BEDOV, S. D. PUSTIL'NIKOVA, R. V. RATNIKOVA and A. A. PETROV, Neftekhimiya 2, 3, 313, 1962 4. S. V. CHERNYAVSKAYA, T. A. FILIMONOVA, V. F. KAM'YANOV, /qeftekhimiya 23, 1, 130, 1983 5. B. M. RYBAK, Analiz nefti i nefteproduktov (Analysis of Petroleum and Oil Products), p. 780, Gostoptekhizdat, Moscow, 1962 6. A. M. KULIYEV, R. Sh. KULIYEV and K. I. ANTONOVA, Naftenovy~ce kisloty (Naphthenic Acids), p. 97, Khimiya, Moscow, 1965 7. N. S. NAMETKIN, L. P. KOLESNIKOVA, T. G. BAIKOVA, A. A. BOBYLEVA, L. K. RUMYANTSEVA and G. V. MOROZOVA, Neftekhimiya 19, 1, 127, 1979 8. R. V. ANBROKH, V. A. GARBALINSKII, A. V. BOGATSKII, Al. A. PETROV and M. L KRASAVCHENKO, Khimiya i tekhnologiya topliv i masel, 8, I1, 1972
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R.N. VOLKOVet aL
9. J. KNOTERUS J. Inst. Petrol. 43, 307, 1957 10. A. A. POLYAKOVA, Molekularnyi mass-spektral'nyi analiz neftei, p. 130, Nedra, Moscow, 1973 11. AI. A. PETROV, Khimiya alkanov, pp. 204, 213, Nauka, Moscow, 1974 12. N. B. VASSOYEVICH, A. N. GUSEVA and I. E. LEIFMAN, Geokhimiya, 7, 1075, 1976 13. G. BREI and G. EVANS, Uglevodorody v materinskikh ottozheniyakh. Symp.: Organicheskaya geokhimiya, pp. 2, 93, Nedra, Moscow, 1970 14. G. EGLINTON, Organicheskaya geokhimiya (Ed. G. Eglinton and T. M. G. Murphy) p. 29, Nedra, Leningrad, 1974
Petrol. Chem. U.S.S.R. Vol. 25, No. 3, pp. 1'44-148, 1985 Printed in Poland
0031-6458/85 $10.00 + .00 © Pergamon Journals Ltd.
OXIDATIVE DEHYDROGENATION OF ETHYLBENZENE ON VANADIUM-MAGNESIUM OXIDE CATALYSTS* R. N. VOLKOV, V. P. PANOVA, I. P. BELOMESTNYKI-I,G. V. SHAKHNOVICHand
~. V. ISAGULYANTS N. D. Zelinskii Institute of Organic Chemistry, U.S.S.R. Academy of Sciences Voronezh Branch of the S. V. Lebedev All-Union Scientific Research Institute of Synthetic Rubber Manufacture (Received 2 January 1984)
PREVIOUS studies [1, 2] showed that vanadium-magnesium oxide catalysts are highly active and selective for the oxidative dehydrogenation of ethylbenzene to styrene. The present work investigates catalyst stability under conditions of continuous operation without recovery. EXPERIMENTAL
Oxidative dehydrogenation was carried out in an adiabatic reactor consisting of five sections (50 x 1850 mm), each section carried an electrically heated lining, a thermocouple and connecting pipes for the supply of air, steam and for sampling; the first section was filled with Raschig rings and served as a mixer. The vanadium-magnesium oxide catalyst prepared by mixing a m m o n i u m metavanadate or vanadium pent0xide, modifying components and magnesium oxide, * Neftekhimiya 25, No. 4, 468--471, 1985.