Vol 11, No 4 (2019)

Works on existing ways of producing Altax (2,2'-dibenzothiazolyl disulfide), an important accelerator of rubber vulcanization, are analyzed. It is shown that the main means of its production is the oxidation of 2-mercaptobenzothiazole (Captax) by different oxidizers (e.g., oxygen in the presence of catalysts, hydrogen peroxide) and electrochemical oxidation. Based on the analysis of the literature data, a small-scale Altax production technology is developed at the Boreskov Institute of Catalysis and tested at a pilot plant designed at the institute’s Volgograd Branch.

The effect of the type of the cobalt-containing component (Со-Al₂O₃/SiO₂, Co-Re/Al₂O₃, and Co-Re/TiO₂) of a composite catalyst on the combined synthesis and hydroconversion of hydrocarbons by the Fischer–Tropsch process are investigated. The catalytic properties of catalyst samples are studied in a flow reactor with a fixed catalyst layer at 2 MPa and GHSV of 1000 h^–1 within a the temperature range of 240–280°С for 40–90 h of continuous operation. The highest values of output and selectivity to C₅₊ hydrocarbons are obtained for composite catalyst Со-Al₂O₃/SiO₂(35%)/ZSM-5(30%)/Al₂O₃(30%) at a temperature of 240°C and are 106 kg/(\({\text{m}}_{{{\text{cat}}}}^{3}\) h) and 67.1%, respectively. It is shown that using Co-Re/Al₂O₃ instead of Со-Al₂O₃/SiO₂ catalyst produces comparable values of catalytic activity, but considerably fewer unsaturated hydrocarbons are found in the products of synthesis. Using Co-Re/TiO₂ catalyst and raising the temperature (to 280°С) shifts the molecular weight distribution of the products of synthesis toward the formation of a gasoline fraction. It is found that the rate of catalyst deactivation grows in the order Со-Al₂O₃/SiO₂ > Co-Re/Al₂O₃ > Co-Re/TiO₂.

The problem of optimizing the textural characteristics and chemical composition of the alumina support of a vacuum gasoil hydrotreating catalyst is considered. The catalyst is synthesized using the state-of-the-art environmentally friendly technology of flash calcination of gibbsite. Ways of increasing its specific surface area by introducing inorganic additives containing boron or sulfur at the stage of synthesizing boehmite with needle-shaped particles are developed. It is established that introducing such modifiers raises S_BET by 50–100 m²/g, relative to the maximum values that can be attained by varying the standard parameters of hydrothermal treatment. It is shown that introducing boron at the stage of boehmite synthesis improves the catalytic activity of CoNiMoP catalyst in the hydrodesulfurization and hydrodenitrogenation of vacuum gasoil by two or more times, relative to a similar catalyst doped with boron from an impregnating solution.

The morphological and structural properties of Pd–CeO₂/Al₂O₃ catalytic compositions annealed at 100, 500, and 1000°С are studied, along with thereof coatings deposited on metallic foil via cold gas dynamic spraying. The influence of the preparation technique of the initial catalytic composition and introducing active component into a coating on their phase states, particle sizes, and activitites is elucidated. It is shown that introducing active components via impregnation into preliminarily sprayed alumina layer ensures the uniform distribution of Pd and Ce in the support profile, the formation of nanosized PdO particles, and the phase of interaction between the components of the catalyst and support. The impregnated catalyst shows the highest activity in the reaction of methane oxidation. The technique for preparing coatings has no limitations when scaled up and can find application in manufacturing full-size catalysts on metallic foil for different types of power engineering devices.

The catalytic combustion of peat, anthracite, and their mixture in a ratio of 40 : 60 wt % was studied. The addition of peat with a high yield of volatiles to anthracite increased the degree of burnout of the mixture. When the commercial aluminum-copper-chromium oxide catalyst IK-12-70 was used (bed height 1 m, process temperature 700–750°C, particle size of solid fuel less than 1.25 mm), the degree of burnout was 98.2% (peat), 50.9% (anthracite), and 74.2% (peat–anthracite mixture). For large particles of a shaped peat–anthracite mixture with an equivalent diameter of 11.6–18.6 mm, burnout in the upper part of the fluidized bed of the catalyst was 80.5%. The degree of burnout of large particles fed into the lower part of the fluidized bed was evaluated taking into account the degree of burnout of small particles that passed the bed. When large particles of the shaped peat–anthracite mixture were fed, burnout reached at least 95% at a temperature of 700–750°C and a catalyst bed height of 1 m. To avoid accumulation of ash particles in the fluidized bed, the particle size of peat and anthracite in the shaped fuel should not exceed 1–1.5 mm when using a catalyst with a particle size of 2 mm.

The review covers the modern trends in the field of biodiesel production from microalgal biomass. It represents the data on the most promising strains of microalgae as the lipid producers. The influence of various medium components, temperature, pH and illumination intensity on microalgae biomass composition, lipid accumulation and their metabolism is observed. Among the substrates used for the cultivation of microalgae, wastewater is the most promising one. Approaches to obtaining biodiesel from microalgae lipids using biocatalytic transesterification with various lipases are considered.