Том 9, № 2 (2017)

Alumina desiccants obtained by extrusion molding of plastic pastes based on pseudoboehmite or bayerite-containing hydroxides including those modified by sodium and potassium ions were studied. The hydroxides were synthesized by hydration of the product of centrifugal thermal activation of gibbsite under mild conditions. The physicochemical and structural-mechanical properties of the desiccants (fresh and after nine adsorption–regeneration cycles) were studied. The dynamic capacity was determined at a pressure of 3MPa under conditions designed to model the industrial conditions. The sample obtained from bayeritecontaining hydroxide had a higher dynamic capacity than the sample obtained from pseudoboehmite-containing hydroxide at close texture and strength characteristics of adsorbents. Modification of the samples obtained from pseudoboehmite-containing hydroxide with potassium and sodium ions leads to decreased granule stability and increased volume, average pore size, and dynamic capacity. The potassium-modified sample of the desiccant had dynamic capacity as high as that of the sample obtained from bayerite-containing hydroxide at low load. After the cyclic tests, the phase composition, alkaline impurity contents, specific surface area, and crushing strength of the samples did not change within the error of determination. It was found that the prepared desiccants were highly stable in many adsorption–desorption cycles and the minimum dew point of –80°C could be reached during the drying.

Monometallic copper and bimetallic palladium-copper catalysts supported on ZnO–Al₂O₃ and ZrO₂–Al₂O₃ were prepared by conventional impregnation method and tested in methanol synthesis reaction under elevated pressure (3.5 MPa) in gradientless reactor at 220°C. The physicochemical properties of prepared catalytic systems were studied using BET, X-ray, TPR-H₂, TPD-NH₃ techniques. The promotion effect of palladium on catalytic activity and selectivity of copper supported catalyst in methanol synthesis reaction was proven. The highest activity of this system is explained by the Pd–Cu alloy formation.

Over the last 20 years, carbon-containing catalysts prepared using carbonized aluminum oxide and various carbon-based materials as carriers, along with metal carbides as active components, have been widely studied in the hydroprocessing of oil fractions. In this work, the properties of different groups of carbon-containing catalysts are discussed. The difficulties of using carbon-based carriers caused by their need for chemical pretreatment (oxidation and leaching), and the application of water–organic infiltrating solutions to form active catalyst components in finely dispersed form, is shown.

A GIP-14 diesel fuel isodewaxing catalyst based on a mixture of zeolites with different pore structures and entrance sizes and transition metals Ni and Mo as hydrogenating components is developed. Its stability during operation is studied. It is shown that the cold filter plugging point (CFPP) of the diesel fuel reaches values below–38°C at its yield of 92–93 wt %, temperatures of 305–310°C, and a feedstock hourly space velocity (FHSV) of 3 h⁻¹. A pilot diesel fuel sample is tested according to GOST (Russian State Standard) R 55475–2013. Comparative tests of domestic and foreign catalysts show that the developed GIP-14 catalyst conforms to international standards and allows the production of diesel fuel with required cold flow properties under milder conditions (300°C against 320–325°C for the foreign catalyst) at a higher FHSV (3 h⁻¹ against 2 h⁻¹). The production of GIP-14 catalyst is planned to be launched in 2017.

Со(Ni)–PMo(W)/Al₂O₃ catalysts are prepared using Keggin heteropoly acids H₃PMo(W)₁₂O₄₀ and cobalt (nickel) citrate. The physicochemical properties of the catalysts are studied via low-temperature nitrogen adsorption, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy. Their catalytic properties are determined in the hydrotreatment of a model raw material containing dibenzothiophene, naphthalene, and different amounts of quinoline (up to 1000 ppm of nitrogen), and in the hydrotreatment of a straight-run diesel fraction and vacuum gas oil. The composition of Со(Ni)–PMo(W)/Al₂O₃ catalysts plays an important role in the hydrotreatment of a complex hydrocarbon raw material. Ni–PW/Al₂O₃ catalyst is more resistant to organonitrogen inhibitors than Ni(Co)–PMo/Al₂O₃ samples with more reactive active sites. Ni–PW/Al₂O₃ catalyst provides the greatest depth of conversion for sulfur- and nitrogen-containing compounds and polycyclic aromatic hydrocarbons in the hydrotreatment of vacuum gas oil.

The catalytic properties of complex perovskite-type gadolinium and strontium oxides in carbon dioxide reforming of methane and the production of gaseous olefins by carbon monoxide hydrogenation have been studied. Samples of Gd₂SrFe₂O₇ and Gd_2–xSr_1+xFe₂O₇ (х = 0.1; 0.2; 0.3; and 0.4) have been obtained by the sol–gel method and ceramic technology, and have been characterized by means of X-ray diffraction, scanning electron microscopy, photon correlation spectroscopy, Mössbauer spectroscopy, and N₂ adsorption–desorption analysis. It has been shown that the sol–gel method allows us to produce samples with better catalytic characteristics than ceramic systems. The nonisovalent substitution of Gd³⁺ for Sr²⁺ distorts the structure of complex oxide, resulting in the emergence of the heterovalent state of iron atoms (Fe³⁺ and Fe⁴⁺) reflected in the values of reactant conversion and selectivity for the target products. A sample of Gd_2–xSr_1+xFe₂O₇ with х = 0.3 displays the highest catalytic activity in dry reforming of methane reforming, along with the highest selectivity for unsaturated hydrocarbons (ethylene and propylene) in hydrogenation of carbon monoxide.

Existing and emerging technologies for the chemical processing of wood are mainly aimed at transforming its cellulose component into target products. In these processes, lignin is produced on a large scale as a waste product, but there are no advanced ways of processing it. This work investigates the effect NiCuМо/SiO₂ catalysts have on the thermal transformation of acetone lignin in supercritical butanol at temperatures of 280, 300, and 350°C. The resulting liquid products are studied via gas–liquid chromatography mass spectrometry, and 13С NMR spectroscopy. It is found that butanol undergoes almost no thermochemical conversions at temperatures below 300°C. Catalysts raise its level of conversion to 36–40 wt %. Under the effect of NiCuМо/SiO₂ catalysts, the yield of hexane-soluble products of acetone lignin thermal conversion at 300°C increases by a factor of 2.4, while the yield of solid residue falls by approximately a factor of 3.3. Catalysts reduce the relative content of methoxyphenols in hexane-soluble products: the content of syringol in particular falls by a factor of 14. According to ¹³С NMR spectroscopy, the catalytic transformation of acetone lignin to liquid acetone-soluble products is accompanied by the breaking of β–О–4 chemical bonds between the structural fragments of lignin and a reduction in the content of methoxyl groups, primarily in the syringyl structural units of the resulting products.