Catalysis in Industry最新文献

Bifunctional catalysts based on NiMo(W) sulfides and ZSM-23-Al₂O₃ composite supports were synthesized, and their properties in the conversion of diesel fractions with different contents of nitrogen (<1; 10 and 20 ppm) were studied. The possibility of using the synthesized catalysts to obtain hydrogenates with a cold filter plugging point of ≤ −38°C that meets the requirements of GOST R 55475-2013 in terms of the content of the gasoline fraction, aromatic compounds, and the derived cetane number is shown. The properties of the developed catalysts based on NiMo and NiW sulfides and the characteristics of hydrogenates obtained are compared. In addition, the properties of the developed samples are compared to those of a commercial imported isodewaxing platinum based catalyst. The developed catalysts were found to be less selective than the reference sample, but have better resistance to N-containing compounds in the feedstock.

Systems for the production, storage, and accumulation of hydrogen are an important line in the development of fundamental and applied aspects of alternative energy. Liquid organic hydrogen carriers (LOHCs), polycyclic forms of the corresponding aromatic compounds, are an effective way of hydrogen storage and release with contents of up to 7.3% by mass. The authors compare LOHCs as potential substrates for hydrogen storage and release systems based on catalytic hydrogenation and dehydrogenation reactions, inclusively, with cyclohexane, methylcyclohexane, decalin, perhydroterphenyl, bicyclohexyl, perhydrodibenzyltoluene, and perhydroethylcarbazole. Some data on the activity and selectivity of Pt-containing dehydrogenation catalysts are presented for each of the perhydrogenated substrates.

An investigation was carried out to study the feasibility of using synthesized acid-bearing carbonaceous catalyst (SO₃H–C and PO₄H₂–C) derived from cassava peel for biodiesel production from waste cooking oil (WCO). The catalyst activity was tested using an autoclave type reactor and three different oil to alcohol ratios (1 : 3, 1 : 5 and 1 : 7) at four different temperatures (50–80°C) for 4 h. Two types of alcohol (i.e. methanol (CH₃OH) and ethanol (C₂H₅OH) were used to understand the efficiency of using alcohol in the process. The study indicates that reaction using high ratio of alcohol (1 : 7) generally produced high yield of the biodiesel compared to other ratios. The yield of the biodiesel also increased with increasing temperature over all the reaction systems. The carbon modified with sulphuric acid catalyst showed the highest yield of ~ 90%, which was obtained at 80°C using a 1 : 7 ratio of WCO : alcohol. It was also observed that reaction with methanol produced better yields compared to ethanol reactions where significant differences were observed across both temperature and ratio. The catalysts were characterized using Fourier transform infrared spectroscopy, X-ray powder diffraction, surface area and pore volume analyses. The catalyst is of interest because it is green, non-toxic and synthesized using cassava peel waste.

The trend of modelling native enzymes is increasing day by day with the motive of mechanistic elucidation of enzyme-catalyzed reactions and the efficiency of catalysts. Most of the metalloenzymes are capable to activate molecular oxygen due to the presence of metal ions. Among these, copper-based metalloenzyme catechol oxidase has an attractive feature of its oxidizing ability to generate ortho-quinones from catechol. Moreover, the conversion of catechol to ortho-quinones is an important tool for the determination of hormonally active catecholamines such as adrenaline, noradrenaline, and dopa. Nevertheless, the use of native enzymes is highly expensive and the employment of biomimetic models can be the best alternative. This review summarizes some of the widely used modelling methods and their successful applications. Additionally, we also briefly elucidated the structure–activity relationship, kinetic studies of the catalytic oxidation of the substrate, and different external factors influencing the catalytic cycle such as pH, temperature, etc.

A review of modern approaches to the development of cobalt catalyst technology used in most known ways of synthesizing hydrocarbons from CO and H₂ using the Fischer–Tropsch is presented. The development of efficient catalysts solves the problem of replacing fossil fuels with ultra-clean alternative fuels and reduces their negative impact on the environment. An analysis of results from scientific and technological research, including ones obtained recently by the authors, shows current lines in developing the technology of high-performance catalysts for the Fischer–Tropsch synthesis of hydrocarbons using classical and integrated GTL technology, including the creation of new types of polyfunctional systems. The review mainly describes the catalytic characteristics of supported cobalt catalysts synthesized via impregnation and polyfunctional hybrid catalysts obtained on their basis for the selective synthesis of fuel fraction hydrocarbons. Problems of controlling selectivity, productivity, and changes in the activity and physicochemical properties of catalysts during long-term operation are considered.

One of a widely used broad-spectrum industrial bactericidal and mildew prevention agents is 1,2-benzoisothiazolin-3-one (BIT). In present study, it was demonstrated that aerobic oxidative cyclization of 2‑mercaptobenzamide (MBA) and 2,2'-disulfanediyldibenzamide (DSBA) in the presence of Mn(OAc)₂ as catalyst allowed to obtain BIT. The mechanism reaction was suggested. It was found that DSBA and MBA can be converted to the BITwith 99% yield at 1.0 mol % Mn(OAc)₂ under 0.3 MPa of oxygen and 100°C for 8 h. Experimental data point that this protocol is both economical and environmentally friendly.

A comparative analysis of industrial zeolite-containing cobalt catalysts for Fischer-Tropsch synthesis with a number of physicochemical parameters is performed. Catalysts containing a heat-conducting additive (aluminum flakes or exfoliated graphite) were tested in an industrial size single-tube reactor (length—6000 mm, inner diameter—12 mm). The testing results of a sample without heat-conducting additive are presented for comparison. It is shown that a catalyst based on support, containing exfoliated graphite is preferable for industrial application at high gas hour space velocities of the syngas due to its higher thermal stability and liquid hydrocarbon productivity.

A review of literature on current results from work in the field of obtaining microalgae biomass and processing it into high-value products (biofuel, ethanol, butanol, hydrogen and other products) by chemical and biotechnological means is performed. The review consists of three parts: Biomass Production Methods, Biofuel Production from Microalgae, and Obtaining High-Value Products via Biotechnology. The first part considers promising strains of microalgae that produce lipids and are used to obtain biofuels that meet standards ASTM D6751 and EN 14214. Information is also given on factors affecting the accumulation and composition of lipids in microalgae (composition, illumination, temperature, and salinity of the nutrient medium). Data are presented on ways of producing microalgae biomass that include the use of flue gases and wastewater.

This review considers and systematizes the results of studying the deactivation of hydrotreatment catalysts currently available in the scientific and technical literature. The effect the composition of the feedstock and the conditions of hydrotreatment have on the coking of catalysts is shown. The reasons for the morphological changes of the active component and the possibility of reducing this type of catalyst deactivation during commercial operation are considered. The effect of a pressure drop on the run time, the action of catalyst poisons, and the ways, in which they enters the hydrotreatment distillates is shown. This information could be useful and interesting to chemical engineers studying catalytic systems, and to workers of oil refining industry.

A study on the efficiency of glass fiber catalysts (GFCs) in the oxidation of hydrogen in a carbon dioxide medium at elevated pressure is performed. Catalyst samples were synthesized from platinum, palladium (as active metals), and heat-resistant high-silica glass fibers, both unmodified and modified with Zr. Catalysts are prepared via surface thermal synthesis and leaching with impregnation. All three tested samples show approximately the same activity, but Pt-based STS is preferred because it uses a much cheaper and widely available glass fibers instead of rare and expensive Zr-modified materials. More than 200 h of life tests for this catalyst show its high stability. The rate of hydrogen oxidation on this catalyst can be described by a kinetic equation corresponding to the law of mass action with a linear dependence on the pressure in the reaction system. The studied GFC can be made in the form of structured cartridges with a small drop in pressure and high intensity of heat and mass transfer under the conditions of the industrial technological process, so its future practical application seems promising.