Petroleum Chemistry (v.55, #7)

Kinetic models of methanol and dimethyl ether conversion to olefins over zeolite catalysts (Review) by S. N. Khadzhiev; M. V. Magomedova; E. G. Peresypkina (503-521).
The review summarizes various approaches to the description of the olefins synthesis kinetics from methanol/dimethyl ether for two types of zeolite catalyst, ZSM-5 and SAPO-34. It has been shown that along with phenomenological models, microkinetic models derived with taking account of the detailed reaction mechanism and quantum-chemical calculations based on the single-event concept of the reaction rate and the transition state theory are being widely used now. Both power laws and the Hougen—Watson equations are proposed to describe the rates of elementary steps.
Keywords: kinetics of ethylene and propylene synthesis; simulation/modelling; methanol; dimethyl ether; MTO process; ZSM-5 and SAPO-34 zeolite catalysts

The carbon isotope composition of individual n-alkanes in samples of crude oil from the Late Devonian play of the Timan—Pechora basin and rock bitumen that reached the main stage of oil generation has been studied. The carbon isotope composition of individual alkanes of thermal bitumen obtained by autoclaving low-maturity Domanik rocks has been also determined. The carbon isotope composition of individual alkanes of the rock bitumen has been shown to correspond to that of the oil samples, a feature that indicates the syngenetic nature of deposits of these Late Devonian oils. The correlation between the oil and bitumen compositions is also confirmed by matching the composition of acyclic hydrocarbons and polycyclic biomarkers of the test oils and bitumens. For the Domanik organic matter, the carbon isotope composition of n-alkanes has been revealed to depend on the temperature of artificial maturation of the rock organic matter, a finding that potentially increases the reliability of the correlation between the oil and source rock organic matter by the isotope data.
Keywords: carbon isotope composition of n-alkanes; biomarkers; catagenesis; crude oil; bitumen; Timan—Pechora basin

Coal tar phenols as a promising intermediate for producing high-performance polymerization inhibitors in petrochemical industry by A. F. Gogotov; A. A. Levchuk; Do Chiem Tai; L. V. Kanitskaya; V. K. Stankevich (530-536).
Variants of the single-step processing of unfractionated crude phenols by phenol—formaldehyde or oxidative oligomerization and/or complexation with organic substrates have been proposed. These treatments result in a significant increase in the inhibitory activity of the phenols and elimination of processing drawbacks of these substrates, such as unpleasant organoleptic properties and high solubility in water, and foremost make it possible to engage coal tar phenols back in petrochemical processes as polymerization inhibitors.
Keywords: coal tar phenols; fractionation; polymerization inhibitor; pyrolysis condensate; phenol—formaldehyde polycondensation; oxidative coupling; “inhibitory systems”

Influence of dispersion medium composition on Fischer—Tropsch synthesis in three-phase system in the presence of iron-containing catalysts by M. V. Kulikova; A. Kh. Al Khazradji; O. S. Dement’eva; M. I. Ivantsov; V. R. Flid; S. N. Khadzhiev (537-541).
The Fischer—Tropsch synthesis over iron-containing catalysts in a three-phase system with synthetic polymers of different compositions introduced into the dispersion medium has been studied. It has been found that these catalysts exhibit activity in the synthesis of liquid hydrocarbons from CO and H2. It has been revealed that the addition of synthetic polymers into the catalyst samples leads to the formation of smaller particles, the size of which depends on the employed polymer, and to an increase in the selectivity for the target product of the synthesis in the entire studied temperature range.
Keywords: Fischer—Tropsch synthesis; ultrafine iron catalysts; three-phase slurry reactors

Selective hydrogenation of diene hydrocarbons over palladium catalysts synthesized by modified electric field-assisted laser ablation by F. N. Putilin; A. N. Shatokhin; F. F. Guliev; I. A. Aksenov; S. V. Kardashev; A. L. Maksimov; E. A. Karakhanov (542-548).
Palladium catalysts have been synthesized by electric field-assisted laser ablation at varying orifice voltage. The catalysts have been characterized by XPS and TEM and tested in the hydrogenation of isoprene and 2,5-dimethylhexadiene-2,4. High catalytic activity has been shown (TOFs = 397 and 158 s−1 for isoprene and 2,5-dimethylhexadiene-2.4, respectively).
Keywords: electric field-assisted laser ablation; heterogeneous catalysis; eggshell catalysts; ultra-low active component content; palladium

Stereochemical features of 1,7-octadiene metathesis on the MoCl5/SiO2–Me4Sn catalytic system by V. I. Bykov; O. B. Chernova; B. A. Belyaev; T. A. Butenko; E. Sh. Finkelshtein (549-551).
It has been established that the metathesis reaction of 1,7-octadiene (OD) proceeds smoothly by two pathways in the direction of the formation of the product of the chain growth, 1,7,13-tetradecatriene, and intramolecular cyclization into cyclohexene. It has been shown that, at the low (9%) conversion of OD, the content of cyclohexene is 72%, while that of 1,7,13-tetradecatriene is 28%. As the reaction proceeds, the content of cyclohexene increases and becomes 97% at the conversion of 99%, i.e., almost all 1,7,13-tetradecatriene formed cyclizes into cyclohexene. At relatively low conversions of OD (9–55%), the stereo-composition of 1,7,13-tetradecatriene does not differ from the stereo-composition of the products of the homometathesis and cometathesis of the linear structures (Z/E=(25–18)/(75–82)). The content of 1,Z-7,13-tetradecatriene decreases sharply from 8.0 to 0.9% with the increase in the conversion. This is explained by a higher proneness of the Z-stereoisomer to the cyclization.
Keywords: olefin metathesis; heterogeneous catalysis; stereochemistry; 1,7-octadiene

Synthesis of ultrafine and binder-free granular zeolite Y from kaolin by M. L. Pavlov; O. S. Travkina; A. N. Khazipova; R. A. Basimova; N. N. Shavaleeva; B. I. Kutepov (552-556).
The laws governing the crystallization of metakaolin to ultrafine zeolite Y in a sodium silicate solution have been studied. Using the resulting zeolite, kaolin, and the additive polyvinyl alcohol, procedures for synthesizing binder-free granular zeolites Y with different silica ratios and properties superior to the known counterparts have been developed.
Keywords: zeolite Y; crystallization; silica ratio; metakaolin; granules

Manufacturing of low-pour-point fuels using high-silica zeolite catalysts by T. P. Kiseleva; M. I. Tselyutina; R. R. Aliev; S. A. Skornikova (557-562).
The results of research and development study on a dewaxing catalyst: improvement in the technology of synthesis of the zeolite component, selection of promotion conditions, and the development of technology for production and use of the catalyst, are presented. It has been found that the hydrothermal treatment of silica gel for 12–24 h at a temperature of 100–120°C leads to the formation of pores of a 100–200 Å radius. Use of the treated silica gel and temperature elevation from 130 to 170°C leads to reduction of the crystallization time from 120 to 48 h and the formation of high-silica zeolite with a particle size of 1–6 µm3. The zeolite promoted with zinc by ion exchange exhibits a higher dewaxing activity than its zinc-promoted samples prepared by impregnating or batch mixing. Furthermore, the introduction of a second promoter (phosphorus compound) into the catalyst reduces the dewaxing temperature by 45°C relative to the initial sample. On the basis of these data, the catalyst production technology as applied to the equipment of the Angarsk plant has been worked out. The designed catalyst DEP-1 in combined use with the hydrotreating catalyst AGKD-400 provides the manufacture of diesel fuel base stock with a cloud point of −38°C, a cold filter plugging point of −41°C (for class 3 diesel), type III according to GOST R 52368-2005 (EN 590: 2009).
Keywords: hydrothermal treatment; high-silica zeolite; promotion; dewaxing catalyst; low-pour-point diesel fuel; pour point; cloud point; cold filter plugging point

On the mechanism and main features of hydroconversion of the organic matter of oil sludge in the presence of nanosized catalysts by Kh. M. Kadiev; N. V. Oknina; A. M. Gyul’maliev; S. G. Gagarin; M. Kh. Kadieva; A. E. Batov; S. N. Khadzhiev (563-570).
The features of hydroconversion of the organic matter of oil sludge have been analyzed by means of chemical thermodynamics and quantum chemistry using as an example the conversion of model organic compounds (aromatic structures, their alkylated and hydrogenated derivatives) in different media. The kinetic characteristics of hydrogenation and hydrogenolysis of the oil sludge have been analyzed in the fractionated feedstock model presented as four pseudocomponents. A scheme of sequential transformations of each of the pseudocomponents with effective rate constants is proposed, in which the rate constant values have been determined from the results of hydroconversion of oil products in a pilot flow reactor unit.
Keywords: wastes; heavy residues; oil sludge; hydroconversion; ultrafine catalyst

Oxidative desulfurization of hydrocarbon fuel with high olefin content by A. V. Akopyan; E. V. Ivanov; P. D. Polikarpova; A. V. Tarakanova; E. V. Rakhmanov; O. V. Polyakova; A. V. Anisimov; V. A. Vinokurov; E. A. Karakhanov (571-574).
The influence of olefins on the oxidative desulfurization of model mixtures and catalytically cracked gasoline has been studied. It has been established using model mixtures and a wide-cut fraction of catalytically cracked gasoline that the presence of olefins in fuel suppresses the oxidative desulfurization process as a result of occurrence of side oxidation reactions of unsaturated compounds. It has been shown that under the given conditions, it is preferable to use neutral catalysts based on transition metal salts for the oxidative desulfurization, rather than catalysts of acidic nature.
Keywords: desulfurization; hydrogen peroxide; fuel; catalytic cracking; peroxo complexes; transition metals

A number of pour-point depressants of the ester and polyaminoaldehyde types have been synthesized. Their physicochemical and dielectric properties have been examined; by comparing these properties, additional information has been obtained to confirm the previously proposed mechanism of action of these additives and compositions thereof on solid petroleum hydrocarbons and the relation of the performance to the dielectric properties of the polyaminoaldehyde additives has been revealed, findings that can facilitate their selection in the development of inhibitors of asphaltene—resin—wax deposition in crude oil.
Keywords: asphaltene—resin—wax deposits; pour-point depressants; modifiers; depressants; inhibitors; oil production; oilfield chemicals; dielectric spectroscopy

Hydrogenolysis of dibenzothiophene on zinc-modified NiMoW/Al2O3 hydrotreating catalysts by N. N. Tomina; S. A. Antonov; N. M. Maksimov; M. V. Samsonov; A. A. Pimerzin (578-584).
The effect of the introduction of ZnO into the NiMoW/Al2O3 hydrotreating catalyst on its activity in dibenzothiophene (DBT) hydrogenolysis has been studied. To select the optimal method for introducing the modifier, a series of samples has been prepared with ZnO added at different stages of the catalyst synthesis. Before the test, the catalysts were sulfided. The catalysts have been tested in the dibenzothiophene hydrogenolysis reaction was under hydrogen pressure using a continuous-flow microreactor. The interrelation of the active phase morphology, as well as the route of addition and amount of the added modifier with the catalytic activity of the samples has been revealed. Modification of the support by adding ZnO in an amount of 0.5 wt % increases the activity of the catalyst in DBT hydrogenolysis.
Keywords: hydrogenolysis; hydrotreating; modification; dibenzothiophene