Theoretical and Experimental Chemistry最新文献

New catalytic methods of hydrodehalogenation reaction of haloarenes for the disposal of toxic production waste and persistent organic pollutants, fine organic synthesis, and solution of green chemistry issues are discussed. Methods presented in the review are based on electron transfer reactions involving photo- and electrocatalytic processes, including those with the participation of metal nanoparticles. Reactions of deuterodehalogenation of haloarenes and several aspects of biological methods of the process are analyzed.

According to molecular docking results (in silico calculations), main protease M^pro of SARS-CoV-2 coronavirus can be blocked by 2-formyl-8-methyl-3-carbethoxy quinoline. The calculations as well as estimation of ADME profile (absorption, distribution, metabolism, and excretion) of this compound provide grounds to consider it as active ingredient against COVID-19 coronavirus, its efficiency is comparable with known inhibitors of SARS-CoV-2. The structure of 2-formyl-8-methyl-3-carbethoxy quinoline is determined by X-ray structure analysis.

According to the quasi-equilibrium NH₃ and CO₂ thermal desorption data, the effect of chromium in the composition of zinc-containing BEA zeolites with different Si/Al ratios on their acid–base characteristics and catalytic properties in the process of dehydrogenation of propane to propene with or without CO₂ has been determined. A positive effect on the propane conversion and the propene selectivity is found for a catalyst based on the initial Cr/ZnAlBEA zeolite (Si/Al = 17). Higher propane conversion is achieved in the process of propane dehydrogenation with the participation of CO₂ in the presence of Cr/Zn-BEA catalysts, but with lower propene selectivity when compared to the propane dehydrogenation process without CO₂.

The promising application of mechanochemical (MC) and sonochemical (SC) synthesis methods for the obtaining of nano-dispersed oxide materials with a perovskite structure (BaTiO₃, CaTiO₃, and LiNbO₃) and higher specific surface value as compared to samples obtained by traditional methods is shown. Synthesized samples exhibit high photocatalytic activity in the oxidative degradation of metronidazole and chloramphenicol drugs, as well as a promethrin herbicide in an aqueous medium exceeding known analogs. The possibilities of MC and SC in the synthesis of zinc and bismuth molybdates with the obtaining of their nanostructures with different morphologies, in particular bars, needles, rods, and spheres, are shown. It is established that prepared samples demonstrate high activity in the processes of ethanol oxidation to acetaldehyde (β-ZnMoO₄) or acetic acid (α-ZnMoO₄), oxidative dehydrogenation of hydrocarbons of the industrial fraction of oil processing with the obtaining of 1,3-butadiene (Bi₂Mo₃O₁₂).

Results of the study of CO₂ methanation on Co-containing catalysts based on Siral aluminosilicates with different SiO₂/Al₂O₃ ratios (1, 10, and 40) are presented. It is shown that methane is the main product at temperatures up to 573 K, its yield varies depending on the SiO₂/Al₂O₃ ratio of aluminosilicate. Carbon monoxide is formed along with methane at temperatures above 573 K. Maximum methane yields of 55% and 41% (at 573 K) are achieved on Co/Siral-1 and Co/Siral-10 catalysts. It is shown that catalysts reduced in a hydrogen flow are characterized by the presence of superpara/ferromagnetic particles and magnetic resonance parameters of their EMR spectra significantly depends on the SiO₂/Al₂O₃ ratio of the aluminosilicate. It is assumed that the superpara/ferromagnetic particles formed during high-temperature hydrogen treatment of Co-containing aluminosilicates are catalytically active particles in the methanation of carbon dioxide.

New carbene complex catalysts based on palladium chloride, including PEPPSI-complexes (PEPPSI = Pyridine-Enhanced Precatalyst Preparation Stabilization and Initiation), have been synthesized. These catalysts show high efficiency in Buchwald–Hartwig C–N cross-coupling between aryl chlorides/bromides and amines, including sterically shielded reagents, and high efficiency in the Suzuki–Miyaura C–C cross-coupling reaction, where their use results in the formation of several tetra-ortho-substituted biaryls at very low amounts of catalyst under mild conditions. Modification of the catalyst structure to the PEPPSI complex leads to an unexpected decrease in activity in the Buchwald–Hartwig amination, in contrast to the Suzuki–Miyaura reaction, in which the PEPPSI complex showed greater activity in some cases.

The catalytic effect of alkali metal carbonates, in situ generated carbene, and anionite in the transesterification reaction of alkyl benzoates with methanol, ethanol, benzyl alcohol, and cyclohexanol, as well as vegetable oils with methanol and ethanol was studied. Catalytic reactions with methanol occur at room temperature with yields close to quantitative. The reactions of the vegetable oils in the presence of potassium carbonate with small amounts of methanol or ethanol (3.2 eq) at room temperature lead to high yields of biodiesel fuel and are suitable for industrial use.

The influence of sulfur on the morphology, spectral, and photocatalytic properties of bulk (S-g-C₃N₄) and crystalline carbon nitride (S-CGCN), obtained by the pyrolysis of melamine–S₈ mixtures and additional thermal treatment of S-g-C₃N₄ in the eutectic melt of KCl and LiCl salts, has been investigated. It is shown that crystalline carbon nitride obtained in the presence of 5 wt.% of S₈ (5S-CGCN) demonstrate the highest photocatalytic activity in the hydrogen evolution process from water–ethanol solutions under the effect of visible light. The effective quantum yield of H₂ formation with the participation of 5S-CGCN and metal co-catalysts (palladium and gold) is Φ ≈ 100% at λ = 405 nm, which is almost twice as much as with the participation of unmodified CGCN. The high activity of 5S-CGCN can be associated with more intensive absorption of light, better separation of photogenerated charges, and suppression of their recombination.

The kinetics of the reaction of glycerol with acetic acid in the presence of natural aluminosilicates treated with nitric acid has been investigated. The influence of a molar ratio of the reagents, the reaction temperature and the catalyst mass fraction on glycerol conversion, as well as a rate of the accumulation of the products and their selectivities has been studied. It is established that in presence of clinoptilolite and trepel, monoacetin is the main product. In the case of bentonite, with the increase in the molar fraction of acetic acid and the catalyst mass fraction, the selectivity of monoacetin decreases due to a diacetin accumulation.