Showing papers in "Petroleum Chemistry in 2008"
TL;DR: In this article, state-of-the-art processes for the manufacturing of lower olefins (mainly ethylene and propylene) from natural gas through methanol, dimethyl ether, and ethanol are surveyed.
Abstract: State-of-the-art processes for the manufacturing of lower olefins (mainly ethylene and propylene) from natural gas through methanol, dimethyl ether, and ethanol are surveyed. The processes involving the synthesis of dimethyl ether via the dehydration of methanol and ethanol production via methanol homologation are discussed.
41 citations
TL;DR: In this article, all theoretically possible isomers of C10−C13 adamantanes and C14−C16 diamantanes are formed, as well as n-alkanes up to C35H72 and coke.
Abstract: Adamantanes and diamantanes, whose abiogenic synthesis from carbon and hydrogen is feasible, were synthesized via the high-temperature cracking of individual n-alkanes in order to reveal the possible ways of the genesis of hydrocarbons with a diamond-like structure. As a result of the high-temperature cracking of n-alkanes, all theoretically possible isomers of C10–C13 adamantanes and C14–C16 diamantanes are formed, as well as n-alkanes up to C35H72 and coke.
22 citations
TL;DR: In this paper, the Anderson heteropoly compounds (NH4)6 − x[Xx(OH)6Mo6O18] · nH2O, where heteroatom X is Cr(III), Mn(II), Fe(II) or Zn(II); and their activity in the thiophene hydrogenolysis reaction and hydrofining of diesel fraction was examined.
Abstract: Unpromoted and nickel-promoted catalysts were synthesized on the basis of the Anderson heteropoly compounds (NH4)6 − x[Xx(OH)6Mo6O18] · nH2O, where heteroatom X is Cr(III), Mn(II), Fe(II), Ni(II), Co(II), Cu(II), Zn(II), or Ga(III), and their activity in the thiophene hydrogenolysis reaction and hydrofining of diesel fraction was examined. It was shown that the most active hydrotreating catalysts under the test conditions in a flow unit were the samples with X = Ni, Mn, or Zn. The catalysts synthesized from the Keggin heteropoly compounds H4[SiMo12O40] · 17H2O, H3[PMo12O40] · 19H2O, H3[PVMo11O40] · nH2O, and (NH4)x[V(MoO3)12] · nH2O were tested in the hydrofining of light coker gas oil. The maximum activity was displayed by the catalysts prepared on the basis of the vanadium-containing heteropoly compounds H3[PVMo11O40] · nH2O and (NH4)x[V(MoO3)12] · nH2O.
22 citations
TL;DR: The effect of magnetic fields on the structural and rheological properties of crude oils with various concentrations of resins, asphaltenes, and paraffin hydrocarbons was examined in this paper.
Abstract: The effect of a magnetic field on the structural and rheological properties of crude oils with various concentrations of resins, asphaltenes, and paraffin hydrocarbons was examined It was found that magnetic treatment leads to substantial changes in the paramagnetic, antioxidant, and viscosity characteristics of paraffin-base and high-viscosity oils A factor that characterizes the quantity of inhibition centers increases with an increase in the amount of alcohol-benzene-extractable resins in the oils The time of complete recovery of paramagnetic and antioxidant properties coincides with the recovery time of the rheological characteristics of petroleum
21 citations
TL;DR: In this paper, it was shown that the performance of the process in an aqueous solution is accompanied by the intense parallel degradation of the cocatalyst, and that relatively high yields of methane oxidation products (largely, formic acid) cannot be attained unless a rather high PCA concentration is used.
Abstract: It was shown that, unlike methane oxidation with the reagent “hydrogen peroxide-vanadate anion-pyrazine-2-carboxylic acid (PCA)” in acetonitrile, the performance of the process in an aqueous solution is accompanied by the intense parallel degradation of the cocatalyst. Therefore, relatively high yields of methane oxidation products (largely, formic acid) cannot be attained unless a rather high PCA concentration is used. Admixtures of a strong acid (sulfuric, trifluoroacetic, or perchloric) increase the yield of the products. It was found that perchloric acid can also be used as a cocatalyst instead of PCA.
21 citations
TL;DR: Publications concerning the current status of understanding of the origin of cage hydrocarbons (adamantanes and diamantanes) occurring in crude oils are surveyed in this article.
Abstract: 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.
20 citations
TL;DR: In this article, the catalytic activity of metal-containing zeolites modified by nanosized Pt, Ni, Fe, and Zn powders was studied in the process of upgrading the petroleum straight-run gasoline fractions.
Abstract: The catalytic activity of metal-containing zeolites modified by nanosized Pt, Ni, Fe, and Zn powders was studied in the process of upgrading the petroleum straight-run gasoline fractions. It was found that the introduction of metal nanoparticles into the zeolite increases the catalyst activity and allows the desired product to be obtained at a lower processing temperature. An enhancement of the aromatization reactions of the hydrocarbon feedstock was revealed on the catalyst samples deactivated in the first reaction cycle and calcined in air.
20 citations
TL;DR: For example, the normalized ratio of position isomers for n-hexane, n-heptane, and n-octane at 50°C in the presence of titanium silicalite TS-1 as a catalyst, forming isomeric mixtures of ketones and alcohols as discussed by the authors.
Abstract: Hydrogen peroxide oxidizes n-hexane, n-heptane, and n-octane at 50°C in the presence titanium silicalite TS-1 as a catalyst, forming isomeric mixtures of ketones and alcohols Admixtures of organic acids, alcohols, benzene, and ethylbenzene sharply change the ratio of position isomers For example, the normalized ratio is C(4): C(3): C(2) = 044: 10: 047 for n-heptane oxidation in the absence of additives, but it becomes 052: 10: 100 in the presence of benzyl alcohol and the addition of ethylbenzene changes it to 016: 10: 094
19 citations
TL;DR: In this article, the octane and cetane numbers of individual hydrocarbons (alkanes and cycloalkanes) were calculated based on an approach to finding structure-property relationships.
Abstract: 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.
16 citations
TL;DR: In this paper, it was shown that the catalysis is mediated by the copper ions on the surface of the solid support, and that the heterogenized catalyst may be reused with some loss of activity, but the initial rates, the yield, and the phenol: quinone ratio depend on the salt chosen and on the presence of 2,2′-dipyridyl as an additive.
Abstract: Copper(II) salts (acetate, perchlorate, and chloride) catalyze the oxidation of benzene with hydrogen peroxide in an acetonitrile solution to give phenol and quinone. The initial rates, the yield of products, and the phenol: quinone ratio depend on the salt chosen and on the presence of 2,2′-dipyridyl as an additive. For example, catalysis by copper perchlorate in the presence of 2,2′-dipyridyl at 50°C results in the formation of phenol and quinone with a yield of 12.5 and 1.5%, respectively (the turnover number reaches 1900). Copper chloride coordinated to solid polymers, poly(4-vinylpyridine) or poly(4-methyl-4′-vinyl-2,2′-dipyridyl), also acts as a catalyst for benzene oxidation into phenol and quinone. It was shown that the catalysis is mediated by the copper ions on the surface of the solid support. The heterogenized catalyst may be reused with some loss of activity.
14 citations
TL;DR: In this paper, the structure and state of active centers of zeolite catalysts (freshly prepared or calcined after the reaction cycle of upgrading the petroleum straight-run gasoline fraction) were studied by means of the X-ray diffraction, UV spectroscopy, and Xray photoelectron spectroscopic techniques.
Abstract: Catalyst samples containing nanosized Pt, Ni, Fe, or Zn powder were prepared on the basis of high-silica zeolite ZSM-5 by mechanical mixing. The structure and state of active centers of zeolite catalysts (freshly prepared or calcined after the reaction cycle of upgrading the petroleum straight-run gasoline fraction) were studied by means of the X-ray diffraction, UV spectroscopy, and X-ray photoelectron spectroscopy techniques. It was shown that the oxidized forms of the metals are practically absent from the freshly prepared zeolite samples. After the heat treatment of the catalysts in air, nanosized metal powders transform into oxides on the zeolite surface, with iron and nickel producing the greatest variety of oxidized forms.
TL;DR: In this article, a promising process for the industrial synthesis of anisole via the vapor-phase alkylation of phenol with methanol in the presence of commercial NaX zeolite was developed.
Abstract: A promising process for the industrial synthesis of anisole via the vapor-phase alkylation of phenol with methanol in the presence of commercial NaX zeolite was developed. A kinetic model of phenol alkylation with methanol was derived.
TL;DR: In this article, the authors studied the synergistic effect of gallium and platinum-modified pentasil zeolites (ZSM-5) with different framework constitutions and determined the optimal zeolite composition and reaction conditions.
Abstract: Ethane aromatization on gallium-and platinum-modified pentasil zeolites (ZSM-5) with different framework constitutions was studied. The optimal zeolite composition and reaction conditions were determined and the synergistic effect of the promoters was revealed. The dependence of the catalyst activity on the SiO2/Al2O3 molar ratio was established. The highest yield of aromatic hydrocarbons (∼30%) and the highest selectivity for their formation from ethane (∼63%) were attained on the (2%Ga–0.3%Pt)/HZSM-5 bimetallic catalyst having SiO2/Al2O3 = 30.
TL;DR: In this article, 2-thiohenedicarboxylic acid esters were synthesized via the reaction of thiophene with the CCl4-ROH-catalyst system, with a total yield of 44-85%.
Abstract: 2-Thiophenecarboxylic and 2,5-thiohenedicarboxylic acid esters were synthesized via the reaction of thiophene with the CCl4-ROH-catalyst system, with a total yield of 44–85%. A possible reaction scheme includes the successive steps of alkylation of thiophene with carbon tetrachloride, leading to 2-trichloromethylthiophene, and alcoholysis of the product giving the corresponding 2-thiophenecarboxylate. The best catalysts for this reaction are VO(acac)2, Fe(acac)3, and Mo(CO)6.
TL;DR: In this article, the reaction kinetics of cyclohexene hydrocarbalkoxylation with cycloshexanol catalyzed by the Pd(PPh3)2Cl2-PPh 3-p-toluenesulfonic acid system was studied over the temperature range 363-393 K.
Abstract: 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
TL;DR: In this article, geochemical studies of chloroform extracts from organic matter (OM) of argillaceous-aleuritic Paleogene rocks drilled by wells in southern West Siberia are reported.
Abstract: 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.
TL;DR: In this paper, the conversion reactions of methanol, ethanol, and their ethers in the presence of acid-base catalysts based on mesoporous ZSM-5 and ZSM11 zeolites, microporous SAPO zeolite, heteropoly acids, and perfluorinated sulfonated cation exchangers are discussed.
Abstract: The conversion reactions of methanol, ethanol, and their ethers in the presence of acid-base catalysts based on mesoporous ZSM-5 and ZSM-11 zeolites, microporous SAPO zeolites, heteropoly acids, and perfluorinated sulfonated cation exchangers are discussed. The set of reactions reflects the formation of olefins beginning from ethylene to butenes. The heats of reaction were estimated from the calculated values of the equilibrium constants and enthalpies at 700 K. It was assumed that the available experimental data for all three types of catalysts should be described by a complex mechanism of transformations of alcohols and ethers. The reaction sequence includes fast dehydration of alcohols into ethers. It is likely that, at temperatures of 512–573 K, the initial reactions have a common initiation mechanism for all three types of catalysts, which involves the formation of the protonated forms of substrate molecules that trigger the olefin synthesis reactions. For thermally stable catalysts (zeolites), the mechanism with participation of free radicals and olefins generated from the alkoxylated hydroxyl groups of zeolites is possible above 573 K. As the degree of conversion of ethers increases, carbenium and arenonium ions begin to play a progressively increasing role as active intermediates instead of the alkoxy groups. This crossover may be responsible for changes in both the kinetic parameters of the substrate transformation and the direction of the reaction over zeolites at 573–623 K. The schemes proposed in some published works for the conversion of oxygen-containing organic compounds and olefins with participation of superacid centers of the catalysts in question should be considered speculations in light of the effect of water leveling the strength of Bronsted sites.
TL;DR: In this article, the appearance of the crystalline phase of high-molecular-mass hydrocarbons with mp at about 55°C was revealed in crude oils and asphaltene-resin-wax (ARW) deposits from long-developed fields of Tatarstan, Orenburg oblast, and Kyrgyzstan were investigated by means of differential scanning calorimetry.
Abstract: Crude oils and asphaltene-resin-wax (ARW) deposits from long-developed fields of Tatarstan, Orenburg oblast, and Kyrgyzstan were investigated by means of differential scanning calorimetry. The appearance of the crystalline phase of high-molecular-mass hydrocarbons with mp at about 55°C was revealed in the oils. It was shown that the crystalline phase of the oils consisted of higher paraffin hydrocarbons of a fairly homogeneous composition with mp > 90°C coprecipitated with asphaltenes. In the ARW deposits, the crystalline phase was represented in the form of separate microcrystal hydrocarbon particles, as well as associated with asphaltenes.
TL;DR: In this article, it was shown that the addition of ethylene to the methane-steam mixture reduces the conversion of methane to carbon oxides and increases coke formation, which is caused by an increase in the contribution of the heterogeneous component of steam reforming.
Abstract: Steam reforming of methane mixtures with ethylene (1.4–3.8 vol % C2H4) in the presence of the industrial nickel catalyst S11-9-09 (12.8 wt % Ni/α-Al2O3) at 750°C was studied. It was shown that the addition of ethylene to the methane-steam mixture reduces the conversion of methane to carbon oxides and increases coke formation. The unfavorable effect of ethylene on the reaction decreases with an increase in the ratio of the catalytic surface area to the free reaction volume. Presumably, this effect is caused by an increase in the contribution of the heterogeneous component of steam reforming, a change that results in an increase in the rate of the interaction of the formed coke with steam.
TL;DR: Tributylhexylammonium bistriflamide was used as a solvent for the Heck reaction of bromobenzene with styrene in the presence of Pd deposited onto a mesoporous carbon support as mentioned in this paper.
Abstract: Tributylhexylammonium bistriflamide [(C4H9)(C6H13)N][(CF3SO2)2N], an ionic liquid, was used as a solvent for the Heck reaction of bromobenzene with styrene in the presence of Pd deposited onto a mesoporous carbon support. It was found that dibutylamine used as a basic reagent to scavenge hydrogen bromide results in higher conversions of the reactants and higher yields of stilbene than sodium acetate. It was shown that the IL is fully recoverable after use in the catalytic reaction.
TL;DR: In this article, data on n-hexane hydroisomerization over Pt, Pd, and Ni catalysts deposited on aluminum-pillared Taganskoe montmorillonite are presented.
Abstract: Data on n-hexane hydroisomerization over Pt, Pd, and Ni catalysts deposited on aluminum-pillared Taganskoe montmorillonite are presented. The activity of the catalysts is compared with the acidity of the specimens and their physicochemical characteristics. It was shown that metals deposited on activated montmorillonite form metal-deposited systems with a uniform distribution of finely divided particles. The size of the palladium particles is about 1.5 times that of platinum.
TL;DR: In this paper, the intensity of biodegradation of crude oil and petroleum products with micromycetes was determined by measuring carbon dioxide evolution and biomass formation, and the conditions for chromatographic analyses of Baku oil, refinery products (diesel fuel, kerosene, and gasoline), and some individual aromatic hydrocarbons (toluene, p-xylene, and ethylbenzene) by micro-cete cultures isolated from Caspian Sea water and coastal soil near the Apsheron peninsula.
Abstract: Degradation of Baku oil, refinery products (diesel fuel, kerosene, and gasoline), and some individual aromatic hydrocarbons (toluene, p-xylene, and ethylbenzene) by micromycete cultures isolated from Caspian Sea water and coastal soil near the Apsheron peninsula was studied. The intensity of biodegradation of crude oil and petroleum products with micromycetes was determined by measuring carbon dioxide evolution and biomass formation. The conditions for chromatographic analyses of biodegradation products were determined. The dynamics of structure and composition of the test petrochemicals during oxidation with micromycetes was studied by means of gas-liquid and gas-solid chromatography and IR and 1H NMR spectroscopy. It was found that, under cooxidizing conditions, microorganisms convert toluene and p-xylene into the corresponding monocarboxylic acids and acetophenone (35–40%) and phenylacetic acid (60–65%) are formed in the case of ethylbenzene.
TL;DR: In this paper, conditions for the synthesis of mono-, di-, tri-, and tetraalkenylhexamethylenetetrammonium chlorides in aqueous solutions were optimized.
Abstract: 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.
TL;DR: In this article, the authors applied the technique of IR spectrometry to the systematic analysis of the group composition of unfractionated oils from Jurassic deposits in southeastern West Siberia, and revealed the existence of three types of oils: methane, methane-naphthenic, and naphthensic-methane.
Abstract: The technique of IR spectrometry was applied to the systematic analysis of the group composition of unfractionated oils from Jurassic deposits in southeastern West Siberia. The existence of three types of oils was revealed: methane, methane-naphthenic, and naphthenic-methane. The territorial and stratigraphic zoning of their occurrence was performed. The characteristic features of the composition of each type of oils were determined, and possible factors facilitating their formation were considered.
TL;DR: In this article, 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(trimsilyl)-ethylene and subsequent methylation of the resulting adduct with methyllithium.
Abstract: 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.
TL;DR: In this article, the deactivation of acid and Zn-containing MFI catalysts in the propane aromatization reaction at high-feed space velocities (600−2400 h−1) and temperatures (550−610°C) was studied.
Abstract: The specifics of the deactivation of acid and Zn-containing MFI catalysts in the propane aromatization reaction at high-feed space velocities (600–2400 h−1) and temperatures (550–610°C) was studied. The kinetics of the buildup of carbonaceous products (coke) was investigated in situ during the catalytic reaction in a thermal analyzer coupled to a mass spectrometer and a gas chromatograph (TA-MS-GC). The nature of the coke was studied by means of differential thermal analysis (DTA) and elemental analysis. It was found that the buildup of heavy coke on the H-MFI zeolite takes place on the outer crystal surface and pore openings, thus leading to a decrease in the propane conversion at the beginning of the reaction. In contrast, light coke appears first and is transformed to heavy coke at later stages on Zn/H-MFI. The light coke leads to a decrease in the yield of methane, ethane, and ethylene, and the heavy coke impedes the formation of aromatic hydrocarbons.
TL;DR: In this paper, it was shown that the introduction of metals into the catalyst composition affects the activity and selectivity of the catalysts and the influence of the addition of water to feedstock on the yields of the desired products was demonstrated.
Abstract: Conversion of dimethyl ether over high-silica zeolite catalysts of the ZSM-5 type was studied. It was shown that the introduction of metals into the catalyst composition affects the activity and selectivity of the catalysts. It was found that the catalysts modified with Zr and P are most selective for light olefins. The influence of the addition of water to feedstock on the yields of the desired products was demonstrated; the results are similar to the data obtained by the Lurgi company.
TL;DR: In this article, a modified alumino-nickel-molybdenum catalyst for the hydrotreating (hydrofining) of oil fractions is proposed, and the high activity of the catalyst in the reactions of the hydrodesulfurization and hydrogenation of aromatic hydrocarbons and resins in the test process is demonstrated.
Abstract: The change of the chemical-group composition of oil fractions of naphtheno-aromatic crude during hydrofining was studied. A modified alumino-nickel-molybdenum catalyst for the hydrotreating (hydrofining) of oil fractions is proposed. The high activity of the catalyst in the reactions of the hydrodesulfurization and hydrogenation of aromatic hydrocarbons and resins in the test process is demonstrated. Deep hydrogenation of polycyclic aromatic compounds and resins results in a considerable increase in the viscosity index of the oil fractions. The conditions of the hydrofining of wide fractions were chosen, and appropriate amounts of the samples for the subsequent hydrogenation in the presence of the catalyst based on noble metals were produced. The hydrofining of oil fractions at the first stage makes it possible to run the second stage of the process (hydrogenation) on a catalyst that is sensitive to the poisonous effect of sulfur.
TL;DR: In this article, a combined process for enhanced oil recovery developed on the basis of inorganic gelforming and oil-displacing compositions were performed in the Las-Eganskoe oil field, Western Siberia.
Abstract: Pilot tests of a combined process for enhanced oil recovery developed on the basis of inorganic gelforming and oil-displacing compositions were performed in the Las-Eganskoe oil field, Western Siberia. The components of the surfactant-based oil-displacing composition were nitrogen compounds that serve in dilute solutions as a nutrient substrate stimulating the growth and oxygenase activity of reservoir biocenosis. Metabolic products that increase the oil-washing efficiency of the composition accumulate during the oxidation of petroleum hydrocarbons. The complex technology suggests the enhancement of oil recovery via an increase in the reservoir sweep efficiency by flooding with the gel-forming composition and in the oil displacement efficiency by the detergent composition and the microbiological component. Field tests of the method were performed on three test areas of the Jurassic horizon of the Las-Eganskoe oil field.
TL;DR: In this paper, the authors studied the kinetics of autoxidation and initiated oxidation of PAO-2 and decene oligomer fractions at 140°C after a hydrogenation process and found that hydrogenation improved all of the kinetic characteristics and increased the oxidation resistance of oligomers.
Abstract: 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.