Petroleum Chemistry (v.57, #1)

Based on the analysis of scientific and patent literature published over the period from June, 2010 to February, 2016, data on catalytic metal complex systems on the basis of chromium with various degrees of oxidation in the reaction of selective tri- and/or tetramerization of ethylene have been systematized and described. Key information about catalytic systems exhibiting high selectivity for higher alpha-olefins (1-hexene and 1-octene) or their mixtures is surveyed.
Keywords: ethylene oligomerization; trimerization; tetramerization; 1-hexene; 1-octene; chromium complexes

Composition and structure of resinous components of heavy oil from the Usa oilfield by T. V. Cheshkova; E. Yu. Kovalenko; N. N. Gerasimova; T. A. Sagachenko; R. S. Min (31-38).
Resinous components of heavy oil from the Usa oilfield have been studied using a set of instrumental methods. The properties of average molecules of resins and their high- and low-molecular weight nitrogen bases have been presented. It has been found that the structure of the resinous components have moieties linked by ester/ether and sulfide bridges. They are represented by normal and branched alkanes, alkylcyclopentanes, alkylcyclohexanes, mono- and polycyclic aromatic hydrocarbons, benzo- and dibenzothiophenes and their homologs, and aliphatic alcohols and acids. It has been demonstrated that the nitrogen bases are structural units of the resin molecules, rather than their peripheral moieties.
Keywords: resins; nitrogen bases; moieties linked by sulfide and ester/ether bridges; structural-group and individual composition

Transformations of resins and asphaltenes of chemically different heavy oils during primary distillation have been studied using oils form the Usa (Komi Republic, Russia) and Zuunbayan (Mongolia) oil-fields as an example. The structural-group parameters of resins and asphaltene molecules of the crude oils and oil residues (fuel oils) obtained via atmospheric distillation involving the withdrawal of IBP–350°C fractions have been determined using elemental analysis, molecular weight, and NMR data. Changes in the average structures of molecules in the primary distillation process of crude oils have been revealed, and it has been found that these changes depend on the chemical composition of the original oils.
Keywords: heavy oils; primary distillation process; resins; asphaltenes; structural-group characteristics

Aggregation of asphaltenes in the presence of dispersant S5A by E. V. Maltseva; A. M. Gorshkov; N. V. Yudina; Yu. V. Loskutova; L. V. Chekantseva; L. V. Shishmina (48-53).
Aggregation of asphaltenes over time in the presence of dispersant S5A has been studied using photon correlation spectroscopy. The addition of the dispersant to toluene solutions of asphaltenes decreases the size of the aggregates, stabilizes their growth, and reduces the rate of aggregation for a considerably long time. The growth stabilization is achieved at the asphaltenes to dispersant ratio of 0.2–4.
Keywords: high-viscosity oil; aggregation; asphaltenes; toluene; dispersant; dispersion; photon correlation spectroscopy

Aryl isoprenoids in crude oils of the Nyurol’ka depression (southeast of Western Siberia) by D. Yu. Chirkova; N. A. Krasnoyarova; O. V. Serebrennikova; Ya. V. Olenev (54-59).
Composition of crude oils from the Nyurol’ka depression has been studied with the aim to reveal the specifics of the composition and its change along the section. It has been found that the main distinctive feature of oils from the Nyurol’ka depression in the southeast of Western Siberia is the presence in most of them of aryl isoprenoids (trimethylalkylbenzenes bearing an isoprenoid alkyl substituent), which never have been detected in crudes from other oil regions of Western Siberia. It has been shown that aryl isoprenoid-containing oils occur over the entire section of the Nyurol’ka depression from the Paleozoic to the Upper Jurassic. The maximal concentration of these compounds has been found in Paleozoic and Lower Jurassic oils occurring in the east and south of the depression. Their amount is 2.4–3.3 times that of alkylbenzenes. Paleozoic oils that do not contain aryl isoprenoids differ from the other oils by the presence of retene and a lower amount of the tri- and tetramethyl derivatives among naphthalenes.
Keywords: Nyurol’ka depression; oil composition; biomarkers; aryl isoprenoids

New resid FCC catalyst for maximizing gasoline yield by Lijun He; Shuqin Zheng; Shao Ren; Hong-Xia Yu; Jian-ce Zhang (60-65).
After surface acidity and pore modifications, the acid strength and pore distribution of composite were improved effectively. FTIR analysis showed that the acid distribution of the modified composite was more concentrated on the range of intermediate and strong acidity. This kind of modification can direct more hydrocarbons to enter into the pores to be converted and remarkably increases the possibility of gasoline forming through a cracking reaction. N2 adsorption–desorption analysis showed that the composite had more meso- and macro-pores with a trimodal distribution. This kind of modification can effectively reduce the mass-transfer resistance in the reaction process and accelerate the diffusion of the product molecules. A FCC catalyst for maximizing gasoline yield was prepared based on the composite. The evaluated results indicated the catalyst can decrease the excessive cracking of mediate distillate and improved the gasoline yield effectively. The gasoline yield had been increased by 2.89%, while the coke yield has been decreased by 0.71%.
Keywords: FCC; catalyst; gasoline; composite; modification

A method for synthesizing unsupported nickel–tungsten sulfide hydrodearomatization catalysts by breaking SPAN-80 surfactant-stabilized nonaqueous emulsions of solutions of different precursors in dimethyl sulfoxide (DMSO) in situ in a hydrocarbon medium has been first studied using ammonium thiotungstate (NH4)2WS4 and 1-butyl-1-methylpiperidinium nickel thiotungstate [BMPip]2Ni[WS4]2 as precursors and nickel nitrate hexahydrate as a nickel source. The synthesized nickel–tungsten catalysts have been characterized by TEM and XPS. The catalytic activity of the in situ synthesized Ni–W particles in naphthalene hydrogenation has been studied at temperatures of 350–400°C and a hydrogen pressure of 5.0 MPa.
Keywords: nickel–tungsten sulfide catalysts; hydrodearomatization; in situ synthesis of catalysts; nonaqueous emulsions; DMSO

An experimental and simulated investigation on pyrolysis of blended cyclohexane and benzene under supercritical pressure by Hao Zhou; Xinke Gao; Penghao Liu; Quan Zhu; Jianli Wang; Xiangyuan Li (71-78).
The pyrolysis characteristics of blended cyclohexane and benzene mixture are investigated under supercritical pressure. The experimental results show that cyclohexane pyrolysis is greatly easier than thermal cracking of benzene, and the addition of cyclohexane can significantly promote the benzene pyrolysis, while the thermal cracking of cyclohexane itself is weakened by the addition of benzene. A simulation of the blended fuel is carried out by using Chemkin program, indicating that the chemical heat sink of cyclohexane pyrolysis can account for nearly 50% of its total heat absorption capacity, while benzene is inactive in thermal cracking process.
Keywords: cyclohexane; benzene; pyrolysis; kinetic modeling simulation; heat sink

Effect of CO2 on the oxidation of cyclohexene by H2O2 using Co1.5PW12O40 catalyst by R. Radman; A. Aouissi; A. Al Kahtani; W. Mekhamer (79-84).
Oxidation of cyclohexene by cheap and environmentally friendly oxidants, namely H2O2 and CO2 has been catalyzed by Co1.5PW12O40. It has been found that the main products of the oxidation are 2-cyclohexen-l-one (enone), 2-cyclohexen-l-ol (enol) and 1, 2-cyclohexanediol (diol) with the enone as the major product. Oxidation by CO2 along with H2O2 remarkably increased the conversion compared to that by CO2 and H2O2 separately. This might be due to the fact that CO2 increases the percarbonate species (HCO4 ) responsible of the oxidation by oxygen transfer, which indicated that the CO2/H2O2 mixture is a useful reagent system. The decrease of both the selectivity of the enone and epoxide in favor of that of diol at higher conversions indicated that the diol was formed from the epoxide by consecutive reaction and/or directly from cyclohexene.
Keywords: cyclohexene oxidation; carbon dioxide; hydrogen peroxide; Polyoxometalates

Deactivation features of gallium-containing zeolites in the propane aromatization process by L. N. Vosmerikova; V. I. Zaikovskii; A. N. Volynkina; A. V. Vosmerikov (85-92).
Conversion of propane to aromatic hydrocarbons on Ga-containing zeolite catalysts prepared by various methods has been examined, and their comparative stability against deactivation has been analyzed. It has been shown that the Ga-containing zeolite catalysts exhibit high activity and stability in propane conversion to aromatic hydrocarbons. Specific features of the formation of carbon deposits on the surface of Ga-containing zeolites in the propane aromatization reaction have been revealed using the techniques of temperature-programmed desorption of ammonia, low-temperature adsorption of nitrogen, differential thermal analysis, high-resolution transmission electron microscopy, and characteristic X-ray spectroscopy radiation. It has been found that the coke deposited on the catalyst has an almost homogeneous structure and is characterized by relatively low degree of polycondensation.
Keywords: propane; aromatic hydrocarbons; zeolite; conversion; activity; selectivity; coke; carbon deposits

Effect of the support nature on the catalytic properties of iron in benzene benzylation by O. I. Vernaya; I. N. Krotova; Yu. V. Maksimov; T. N. Rostovshchikova (93-99).
The effect of the support nature on the dispersion, structure, and catalytic activity of iron oxides supported on ZrO2, TiO2, ZnO, Al2O3, and silicas of different structures has been analyzed using the example of benzene benzylation. The structure and electronic properties of the catalysts prepared from iron acetylacetonate have been studied by Mössbauer spectroscopy. It has been shown that the use of SiO2, ZrO2, and ZnO supports characterized by weak oxide–oxide interaction leads to the formation of small iron oxide clusters of a 2–10 nm size, which exhibit the highest activity in catalysis.
Keywords: iron oxide; alkylation; catalysis; nanoparticles; oxide supports; Mössbauer spectroscopy

Synthesis of a novel efficient antioxidant for use in lubes and biodiesel by Raj K. Singh; Aruna Kukrety; Om P. Sharma; Mukesh K. Poddar; Neeraj Atray; Siddharth S. Ray (100-105).
A novel phenolic ester Bz-3-tBz was synthesized by reaction between 1,3,5-benzenetricarboxylic acid chloride and 3,5-di-tert-butyl-4-hydroxybenyl alcohol using N,N’-dimethylacetamide solvent and N,N’-dimethylaminopyridine as catalyst. The additive Bz-3-tBz was characterized by CHN, FT-IR, NMR and TG. The Bz-3-tBz was then evaluated as antioxidant additive in polyol by the rotatory bomb oxidation test (RBOT) as per ASTM D2272. The RBOT time for the blank sample containing only polyol base was observed to be 6 min 43 sec. It was observed that Bz-3-tBz in 3000 ppm concentration enhanced the RBOT time to the 15 min 46 sec. It was a significant increase of 2.35 times. The oxidation stability of biodiesel was also found to be increased when Bz-3-tBz was added in to it. The value of induction time determined by the Rancimat test for the biodiesel at 130°C was 0.60 h which was increased to 3.14 h at 2000 ppm Bz-3-tBz concentration.
Keywords: phenolic-ester; antioxidant; RBOT; Rancimat; polyol; biodiesel

The role of sulfur in modification of active sites of reforming catalysts by V. Yu. Tregubenko; A. G. Proskura; A. S. Belyi (106-113).
The features of the interaction of hydrogen sulfide with the surface of supports (alumina and silica) and catalysts (Pt/SiO2, Pt/Al2O3, Re/Al2O3, and Pt–Re/Al2O3) have been studied. It has been found that the adsorption of sulfur on the supports is completely reversible. The amount of irreversibly adsorbed sulfur (Sirrev) and Sirrev/metal ratios in the catalysts after treatment in a hydrogen atmosphere at 500°C have been determined. Sulfurization reduces the dispersion of platinum to 5% and increases the amount of ionic platinum on the catalyst surface. Regarding the dehydrocyclization reaction of n-heptane, the optimal amount of sulfur required for sulfurization of the catalyst with the composition 0.25% Pt 0.3% Re/γ-Al2O3 (0.3% Zr) is 0.072 wt %.
Keywords: reforming catalysts; active sites; sulfurization; sulfur; sulfur adsorption; dehydrocyclization of n-heptane

Multisensory stripping voltammetry as a method for identifying jet kerosenes by V. P. Lukovtsev; A. N. Doronin; V. A. Semenova; N. V. Lukovtseva; K. V. Shatalov; I. M. Nikitin (114-116).
The possibility of using multisensory stripping voltammetry to identify jet fuels has been explored. It has been shown that this method allows differentiation between kerosene fractions obtained using different refining processes.
Keywords: jet fuel; kerosene fraction; straight distillation of crude oil; oil hydrotreating; multisensory inversion voltammetry