Vol 57, No 12 (2017)

The hydrogenation of petroleum resins (PRs) and the possibilities of using light hydrogenated PRs as components of hot-melt adhesives and pressure-sensitive adhesives have been surveyed. The theoretical aspects of hydrogenation of high molecular weight compounds and the influence of the main factors, such as average molecular mass, structure of hydrogenated moieties, catalyst support morphology, and solvent nature, on the extents of the hydrogenation and chain degradation reactions and their competition have been analyzed. Catalysts and processes for PR hydrogenation have been considered, and the appropriateness of using unsupported nanosized catalysts that mediate the process without diffusion limitations has been substantiated. The possibilities of using hydrogenated PRs in adhesive compositions with regard for compatibility with polymers and rheological and adhesion properties are described. Promising fields of research in hydrogenation of polymeric materials have been identified, including hydrogen-donor hydrogenation, in situ synthesis of sulfides in polymer solutions, particle size optimization of the active phase for hydrogenation of polymers with different average molecular masses, and highly selective hydrogenation of polymers.

In this research article, spectrophotometric method for the determination of iron with 1,10-phenanthroline (phen) in two different crude oil samples from different oil fields in the Suez-Gulf region of Egypt has been proposed. The method is efficient, reliable and inexpensive where a cost-effective technique, along with commercially available spectrophotometric reagent, was utilized in this work. The method was based on decomposition of the organic matrix by combustion in a heating muffle furnace at 550°C. The inorganic residue was then dissolved in diluted nitric acid and the iron was reduced to the divalent state. The color was developed by the addition of 1,10-phenanthroline as chelating agent after adjusting the pH of the solution, then the absorbance of the solution was measured at approximately 510 nm after a short reaction period. The limit of detection (LOD) and limit of quantification (LOQ) obtained were found to be 0.017 and 0.051 μg/mL, respectively. The effect of interferences was studied and the accuracy of the method was evaluated by recovery experiment, analysis of oil reference material and by comparison of results with those obtained using flame atomic absorption spectrometer (FAAS) after dilution in an organic solvent for sample preparation.

Four catalyst precursors were prepared to assess the performance on the upgrading process of heavy oil. It has been showed that viscosity of Lukeqin heavy oil was decreased significantly, which revealed a viscosity reduction ratio of up to 99.28% with a catalyst precursor concentration of 0.12 wt %, reaction temperature of 365°С and reaction time of 40 min. Analysis of the oil after upgrading showed an obviously change in the composition of hydrocarbon components. The increase of light fractions after reaction improved the properties of heavy oil which is benefit to the pipeline transportation and downstream refining. Meanwhile, the mechanism of upgrading was also investigated. This work proved that heavy oil can be effectively upgraded with the catalyst precursor of petroleum acid iron.

The process of partial catalytic oxidation of a propane–butane mixture with atmospheric oxygen in a pilot unit has been accomplished. Comparative tests with α-Al₂O₃-supported nickel catalysts and a pressed metal wire catalyst (PMC) made from 12Kh18N10Т steel wire of a 0.2 mm diameter have been conducted. In both cases, byproducts (СН₄, СО₂, and coke) are formed along with the target products (Н₂, СО). It has been shown that the compositions of the resulting synthesis gas are close; however, the Н₂/CO molar ratio is closer to 2 in the case of PMC catalyst, which meets the requirements of the subsequent Fischer–Tropsch synthesis. Problems associated with coking and complete degradation of the structure of the α-Al₂O₃-based catalysts have been revealed and explained in terms of the low efficiency of heat removal from the surface and the formation of carbon in micropores followed by its expansion. These phenomena are characteristic of 12Kh18N10T PMC to a substantially lesser extent and have a local character, suggesting that this catalyst holds promise for its further investigation.

Systematic studies of olefin synthesis from dimethyl ether (DME) in the presence of a hydrothermally treated HZSM-5 zeolite catalyst modified with magnesium have been conducted. Dependences of DME conversion, product yield and selectivity, and lower olefin ratio on space time in the temperature range of 320–360°C have been analyzed. The type of the resulting products has been determined, and assumptions about the reaction chemistry have been made to reveal the role of methylation and hydrogen-transfer reactions in the products formation.

Mono- and bimetallic Mo(W)S₂ catalysts supported on γ-Al₂O₃ and SBA-15 have been prepared using the Keggin heteropoly acids (HPAs) H₄SiMo₁₂O₄₀ and H₄SiW₁₂O₄₀. The catalyst samples have been analyzed by temperature-programmed reduction with hydrogen, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy. Catalytic properties have been examined in the joint hydrotreating of dibenzothiophene and naphthalene on a flow-through unit. It has been shown that the use of mesoporous silica SBA-15 as a support can reduce the average length of Mo(W)S₂ particles from 4.9 to 3.7 nm and increase the average number of layers and the particle size of the active phase, changes that lead to an increase in catalytic activity by a factor of ~3 relative to the alumina-supported counterparts. The use of a mixture of SiMo₁₂HPA and SiW₁₂HPA for preparing MoW catalysts leads to a significant enhancement of catalytic activity, which is apparently due to the formation of mixed active sites.

Hydrogenolysis of glycerol to 1,2-propylene glycol at 200°C in the presence of Cu/Al₂O₃ catalysts prepared by coprecipitation from copper nitrate and aluminum nitrate using NaOH and NH₄OH has been studied. The kinetics of the reaction is described by the first-order rate law. It has been found that the selectivity for the target product for all catalyst samples is 98% and the activity of the catalysts depends on their synthesis conditions. By using X-ray diffraction analysis, transmission electron microscopy, energy dispersive X-ray analysis, and X-ray photoelectron spectroscopy, it has been revealed that the active phase of Cu/Al₂O₃ samples is made of particles with an average size of 20 to 140 nm, whose surface consisted of CuO and Cu₂O. The catalysts with different particle sizes the active phase but close chemical composition exhibits comparable activity (67.5 ± 5 h^–1mol^—1). This finding indicates that the hydrogenolysis reaction run in the presence of Cu/Al₂O₃ is not structure-responsive. A decrease in concentration of the Cu₂O phase of the catalyst leads to a decrease in the hydrogenolysis rate, thereby this indicating a higher activity of the Cu₂O phase in comparison with the CuO phase.

A series of triesters of 3,5-bis(carboxymethyl)-1-adamantanecarboxylic acid have been synthesized and their physicochemical and thermo-oxidative properties have been studied. The properties of the obtained triesters have been compared to those of trioctyl trimellitate, which is used as a plasticizer and a component of various lubricating materials.

A novel method of catalytic thermometric titration has been developed for the determination of the acidity of oils using titration with KOH in isopropanol as titrant. The amounts of oil, concentration and delivery rate of titrant, volumes and types of thermometric end-point indicator were investigated. The results show that mixture of acetone and chloroform used as indicator exhibits strongly exothermic effects to reflect end point obviously. The results obtained from the thermometric titration have good agreement with standard potentiometric and visual titration methods. The procedure is fast, easy to use, accurate, and highly reproducible to measure lower acidity in coloured oils. It is very suitable for the routine process and quality control of many types of oils.

Experimental data have been obtained to evaluate the catalytic activity of copper chelate Cu(NO•)₂ with the paramagnetic ligand in the degradation reactions of hydroperoxide and diacyl peroxide in the aprotic solvent chlorobenzene or in ethyl alcohol, which is capable of forming intermolecular hydrogen bonds. The presence of paramagnetic centers in the ligand have an insignificant effect on the catalytic activity of the copper chelate in the reaction with tetralyl hydroperoxide and benzoyl peroxide in chlorobenzene as compared to another compound CuL₂, which have no paramagnetic centers in the ligand. The catalytic activity of Cu(NO^•)₂ has been found to increase during the reaction with benzoyl peroxide in chlorobenzene, in contrast to CuL₂, which is completely deactivated in this reaction. The EPR spectra of the chelate Cu(NO^•)₂ exhibit a signal due to the nitroxide radical alone. The signal of the central Cu atom is not observed; i.e., there is the case of EPR-undetectable copper in this coordination compound.

The oxidative desulfurization of crude petroleum from the Maiorskoe field (Orenburg oblast, Russia) with hydrogen peroxide in the presence of organic and inorganic acids has been studied. A procedure for the recovery of oxidized sulfur-containing compounds from the petroleum by extracting the oxidation products with polar solvents (N,N-dimethylformamide, acetone, methyl ethyl ketone, or methanol) or thermal decomposition of oxidized sulfur compounds has been selected. As a result of the oxidative desulfurization, up to 80% total sulfur is recovered from the petroleum, with the change in the physicochemical characteristics of the petroleum being insignificant.

On the basis of published reference data on crude oils recovered from more than 300 Russian oilfields, the effect of the concentrations of paraffin waxes, resins, and asphaltenes on oil properties has been analyzed. There are correlations between the oil density, viscosity and the resin content, whereas the amount of asphaltenes (along with resins) has a greater effect on the oil quality characteristics, such as sulfur content, coke and petroleum diesel yields. Crystallizable paraffins do not have a significant effect on the properties of the oils, the pour point of which does not depend explicitly on the composition.

Zeolite MCM-22 (MWW framework type) refers to a class of promising molecular-sieve catalysts that have unique morphology, microporous structure, and physicochemical properties. Studies on the synthesis of these materials have been surveyed. The influence of structural features on the physicochemical and catalytic properties has been assessed. The results of examination of their catalytic activity and selectivity in the petrochemical processes have been discussed.

A dual-bed catalytic system including MoS₂/Al₂O₃ and Co–MoS₂/Al₂O₃ catalysts is proposed for the process of production of diesel fuel with the sulfur content of less than 10 ppm from a straight-run diesel fraction containing 10–45 wt % rapeseed oil. The conversion of rapeseed oil to alkanes proceeds in the MoS₂/Al₂O₃ catalyst bed via the route of “direct” hydrodeoxygenation without the formation of carbon oxides, and the hydrodesulfurization of the diesel fraction occurs in the bed of the Co–MoS₂/Al₂O₃ hydrotreating catalyst. Using this system provides an increase in the yield of diesel fuel and a decrease in the formation of greenhouse gases in comparison with conventional Co(Ni)–MoS₂/Al₂O₃ catalysts.

The influence of various characteristics of NiMo/Al₂O₃ guard-bed catalysts on their activity in the removal of silicon from the diesel fraction has been studied. It has been shown that an increase in the Ni and Mo content leads to a decrease in the amount of trapped silicon in the samples, thereby enhancing the activity of the catalysts in hydrodesulfurization. It has been found that catalysts with an average pore diameter above 130 Å have the highest silicon-trapping activity.

Cobalt- and iron-containing dispersions that can be used as active catalysts for Fischer–Tropsch (FT) synthesis in slurry reactors and a new modification of this process based on the use of nanoheterogeneous catalysis approaches have been discussed. Synthesis procedures for the catalytic dispersions and specific features of occurrence of FT synthesis in the presence of these catalysts have been described.

A comparative study of the trends in ion exchange of NaX zeolite (molar ratio Si/Al = 1.34) pelletized without binder has been performed using successive treatment with calcium, lanthanum, and ammonium nitrate solutions at 80°C with intermediate calcination after each ion exchange stage or by ion exchange in an autoclave at 180°C with calcium nitrate and lanthanum and ammonium nitrate solutions without intermediate calcinations. It has been found that for the complete replacement of sodium cations in the zeolite framework (less than 1 wt % residual sodium oxide), a fourfold ion exchange at 80°C with vigorous stirring and intermediate calcinations or a twofold ion exchange at 180°C in an autoclave without intermediate calcinations is required. Comparison of the physicochemical and catalytic properties of the obtained catalyst samples with almost identical chemical composition has shown a significant advantage of ion exchange in the autoclave, since the zeolite retains its initial structural characteristics.

The substitution of silica gel for γ-Al₂O₃ to be used as a support for a nickel sulfide catalyst for stearic acid decarbonylation leads to a significant increase in the catalyst activity and a slight improvement of the heptadecene selectivity. Comparison with the γ-Al₂O₃-supported catalyst has been made in terms of the kinetic model based on experimental data. An increase in the catalyst activity is attributed to a decrease in the strength of the active site–reactant adsorption complexes on the basis of the Sabatier–Balandin principle. Relationships between the features of the reaction mechanism, the acidity of the support, and the nanoparticle size of the active substance have been discussed.