Petroleum Chemistry (v.48, #4)

Geochemistry of cage hydrocarbons by G. N. Gordadze (241-253).
Publications concerning the current status of understanding of the origin of cage hydrocarbons (adamantanes and diamantanes) occurring in crude oils are surveyed. The aspects of their use in petroleum geochemistry are discussed.

The formation of the composition of unrecovered oils in producing oil fields of Tatarstan by L. M. Petrova; G. V. Romanov; T. R. Foss; N. A. Abbakumova (254-259).
Analysis of the composition of unrecovered and produced oils of Tatarstan shows that the adsorption-chromatographic process upon oil motion in the reservoir during recovery is manifested in an increase in the density and viscosity of unrecovered oils. They do not contain light hydrocarbons of the IBP −200°C fraction and have dramatically smaller concentrations of both the least polar lube oil hydrocarbons and alcohol-benzene-extractable resins exhibiting the highest polarity. According to GLC data, unrecovered and produced oils are classified with different subtypes of chemical type A1 of nonbiodegraded oils: produced oils are grouped with subtype 1 and unrecovered oils are attributed to subtype 2. The dynamics of the development of areas of produced oils with the use of a technique based on the activation of reservoir microflora showed that the process of the microbiological oxidation manifests itself in the preferential ability of reservoir microflora to digest C12-C34 n-alkane hydrocarbons as compared to cyclic hydrocarbons. Normal C12-C20 alkanes are consumed by bacteria before hydrocarbons with a greater number of carbon atoms C20-C34 of this series. An analysis of extracts from aqueous infusions of oils showed that the dissolution process leads to the transfer of 0.04–0.07 wt % hydrocarbons and heteroatomic components from oil to water.

A study of crude oils from the Koltogor rift and its adjacent regions showed that the composition of aromatics does not depend on the oil occurrence depth and is determined by the conditions of the accumulation of the source organic matter, as well as by the tectonic structure of the area.

Biomarker hydrocarbons in the organic matter of Paleogene sediments in southern West Siberia by V. A. Kashirtsev; A. E. Kontorovich; V. I. Moskvin; A. Yu. Kuchkina; V. E. Kim (269-276).
Results of geochemical studies of chloroform extracts from the organic matter (OM) of argillaceous-aleuritic Paleogene rocks drilled by wells in southern West Siberia are reported. Judging from the prevalence of odd over even n-alkanes, as well as the simultaneous presence of terpenes, biohopanes, and regular petroleum hopanes (in 17a(H),21β(H) configuration), the OM of the sediments passed the step of the diagenetic transformation but did not exit from the protocatagenesis zone, i.e., it did not reach the oil window. Taraxerene and olean-12-ene were detected at depths of 90–120 m. At depths greater than 400 m, oleanane and a number of quite rare triterpenoids, such as 28,30-bisnorhopane-17(21)-ene and its reduced analog 28,30-bisnorhopane, appear in trace amounts. Most of the array of triterpenoids are characteristic of terrigenous OM, whereas the pattern of the distribution of tricyclic cheilanthanes in some samples is typical of marine sediments. In character, it is close to the set of the biomarker molecules identified in extracts of Holocene and Miocene deep-sea sediments from Baffin Bay.

Models for the calculation and prediction of the octane and cetane numbers of individual hydrocarbons by A. L. Lapidus; E. A. Smolenskii; V. M. Bavykin; T. N. Myshenkova; L. T. Kondrat’ev (277-286).
Based on an approach to finding structure-property relationships, we constructed models for calculating the octane and cetane numbers of individual hydrocarbons (alkanes and cycloalkanes). The models obtained for octane numbers are superior to well-known analogous models described in the literature in terms of the accuracy and predictive efficiency. This is the first attempt to develop a model of this kind for the cetane number. The results of the calculations of these characteristics for a number of unsynthesized and uncharacterized compounds are given.

The reaction kinetics of cyclohexene hydrocarbalkoxylation with cyclohexanol catalyzed by the Pd(PPh3)2Cl2-PPh3-p-toluenesulfonic acid system was studied over the temperature range 363–393 K. The reaction rate was found to be a nonlinear function of the Pd(PPh3)2Cl2 concentration or a nonmonotonic function of the PPh3 and cyclohexanol concentrations or p CO. The experimental data were interpreted in terms of a mechanism that involves ion pairs containing alkyl and acyl palladium complexes of the cationic type as intermediates. Based on the quasi-steady-state approximation, a rate equation was obtained to adequately describe the experimental data. The rate equation parameters were estimated using the least squares technique. The apparent activation energies of these parameters were determined. The heats of formation of Pd(PPh3)2(C6H11OH)2, Pd(PPh3)2(CO)2, and Pd(PPh3)4 complexes from Pd(PPh3)2(C6H5CH3)2 were estimated. A symbatic change in these values with the donor-acceptor properties of ligands was demonstrated.

Effect of hydrogenation on the oxidation resistance of decene oligomers by T. A. Bazanov; L. V. Petrov; B. L. Psikha; S. B. Psikha; V. V. Kharitonov (296-301).
The kinetics of autoxidation and initiated oxidation of PAO-2, PAO-4, PAO-6, and PAO-10+ decene oligomer fractions at 140°C after a hydrogenation process was studied. Key reactions in the mechanism of oxidation were identified; the numerical values of the kinetic parameters were determined, and mathematical models, which quantitatively described the experimental data on the consumption of oxygen and the buildup of hydroperoxides during the course of the oxidation of the test samples, were obtained. The oxidation resistances of hydrogenated fractions were compared with each other. It was found that the kinetic parameters of the test samples were similar, and the oxidation of all of the hydrogenated oligomers occurred by approximately the same processes. Using the PAO-2 fraction at 120, 130, and 140°C as an example, the oxidizability of hydrogenated and unhydrogenated samples was compared. It was found that hydrogenation improved all of the kinetic characteristics and, consequently, increased the oxidation resistance of oligomers. However, the oligomers remained readily oxidizable substances, particularly, at elevated temperatures.

Synthesis and metathesis polymerization of 5,5-Bis(trimethylsilyl)norbornene-2 by M. V. Bermeshev; M. L. Gringolts; V. G. Lakhtin; E. Sh. Finkel’shtein (302-308).
5,5-Bis(trimethylsilyl)norbornene-2 was synthesized in a yield of 60% via the scheme of diene condensation of cyclopentadiene with 1,1-bis(trimethylsilyl)ethylene and subsequent methylation of the resulting adduct with methyllithium. Its metathesis polymerization was first performed on W and Ru catalysts with yields of up to 98%. The structure of the new polymer was determined by means of the NMR and IR techniques. The tungsten catalyst makes it possible to prepare the polymer with a 40% amount of trans-double bonds, whereas the ruthenium catalyst is more selective and yields the polymer that contains almost 100% trans-double bonds. A high glass transition temperature as compared to other silicon-substituted metathesis polynorbornenes (196–203°C) indicates a high rigidity of the polymer chain and suggests that the polymer will have good gas-separation properties.

Synthesis of energetic compounds via the metathesis reaction of 4-methylenespiro[2,3]hexane by S. V. Kotov; S. P. Chernykh; E. Sh. Finkel’shtein; B. S. Strel’chik; V. A. Tyshchenko; V. I. Milovantseva (309-313).
Transformations of methylenespiro[2,3]hexane (MSH) on a heterogeneous rhenium-alumina metathesis (disproportionation) catalyst were studied. It was found that, owing to a significant difference in the stability of carbenic complexes of methylene and disubstituted carbenes, MSH undergoes isomerization to 4-methylspiro[2,3]hex-4-ene followed by their cometathesis yielding bis(spiro[2,3]hexylidene-4). The feasibility of selective cometathesis of MSH and dicyclobutylidene on the rhenium-alumina catalyst resulting in the formation of 4-cyclobutylidenespiro[2,3]hexane was shown.

Quaternary ammonium salts were synthesized on the basis of hexamethylenetetramine and piperylene hydrochloride. Conditions for the synthesis of mono-, di-, tri-, and tetraalkenylhexamethylenetetrammonium chlorides in aqueous solutions were optimized. The main physicochemical characteristics of the synthesized compounds were determined and the structures were established. The suppression of the growth of sulfate-reducing bacteria was studied.

The influence of the temperature of a medium on the IR absorption spectra of water dissolved in aromatic hydrocarbons was studied. It was found that the temperature of the medium substantially influences the accuracy of the determination of the quantity of dissolved water. In addition, the energy of the molecular interaction between dissolved water and an aromatic hydrocarbon was calculated on the basis of the experimental data. The results make it possible to optimize the operation of industrial spectral analyzers with the purpose of decreasing the determination error.

Enhancement of the efficiency of the process of mild catalytic oxidation of methane by O. A. Timonova; A. V. Kamenev; G. Z. Kaziev; Yu. S. Mardashev (322-323).
A model of in-series connected reactors for the mild oxidation of natural gas that makes it possible to use a high selectivity of catalysts for a higher conversion of the gas to the desired product is proposed.

IX School-Conference for Young Scientists on Petroleum Chemistry by Tat’yana Valerianovna Soboleva (324-324).