Alexander L. Kustov

Lanthanum cobaltite perovskite supported onto mesoporous zirconium dioxide: Nature of active sites of VOC oxidation

Novel catalytic nano-sized materials based on LaCoO(x) perovskite nanoparticles incapsulated in the mesoporous matrix of zirconia were prepared, characterized by physicochemical methods and tested in complete methanol oxidation. LaCoO(x) nanoparticles were prepared inside the mesopores of ZrO(2) by decomposition of bimetallic La-Co glycine precursor complexes. The catalysts have been studied by diffuse-reflectance FTIR-spectroscopy using such probe molecules as CO, CD(3)CN and CDCl(3) to test low-coordinated metal ions. At low temperatures of decomposition of complexes (up to 400°C), low-coordinated Co(3+) ions predominate in the LaCoO(x) nanoparticles, whereas basically Co(2+) ions are found upon increasing the decomposition temperature to 600°C. The novel nano-sized perovskite catalysts exhibit a very high catalytic activity in the abatement of volatile organic compounds present in air, like methanol and light hydrocarbons.

Oxidation of Carbon Monoxide over MLaOx Perovskites Supported on Mesoporous Zirconia

The oxidation of CO was studied on a series of MLaO3 perovskites (M=Co, Fe, Ni) supported on mesoporous zirconia that are synthesized by using a glycine‐mediated method and characterized by using X‐ray photoelectron spectroscopy, X‐ray absorption spectroscopy, and diffuse reflectance infrared Fourier transform spectroscopy. The activity of the catalysts in the CO oxidation reaction follows the order Co>Ni>Fe.

Further Steps of Zeolites Toward Industrial Applications: A Short-Range Outlook

This review of zeolite applications in various processes of commercial interest is focused on very recent achievements and takes into account a great pool of new zeolite-like and similar new materials, including organic-inorganic hybrid systems and hierarchical materials. Diverse types of reactions are summarized including hydrocarbon processing, hydrogenation, partial oxidation and other processes where zeolite materials can find application.Abstract This review of zeolite applications in various processes of commercial interest is focused on very recent achievements and takes into account a great pool of new zeolite-like and similar new materials, including organic-inorganic hybrid systems and hierarchical materials. Diverse types of reactions are summarized including hydrocarbon processing, hydrogenation, partial oxidation and other processes where zeolite materials can find application.

Partial oxidation of toluene with nitrous oxide under supercritical conditions

The partial oxidation of toluene with nitrous oxide over the H-ZSM-5 catalyst under supercritical conditions at temperatures of 370–420°C and pressures of 70–160 atm has been investigated for the first time. The maximum cresol selectivity under these conditions is 32%. The amounts of the resulting cresol isomers form the following decreasing sequence: m-cresol > o-cresol > p-cresol. The partial oxidation of toluene is accompanied by disproportionation and biphenyl formation.

The use of a fiber-optic densitometer for monitoring the density of the reaction medium during catalytic reactions conducted under supercritical conditions

The possibility of using a fiber-optic densitometer to monitor the density of the reaction medium during heterogeneous catalytic reactions has been shown using the example of the alkylation of isobutane with butenes conducted under supercritical conditions at 150°C and 80 atm. The density has been measured at two points—before and after a fixed bed of an H-USY catalyst. The dependences of the density and refraction of the isobutane-butene mixture on temperature and pressure have been plotted.

Catalytic oxidative coupling of dimethyl ether under supercritical conditions

Catalytic oxidative coupling of dimethyl ether (DME) is studied for the first time under supercritical conditions. The oxidation of DME with molecular oxygen of air in the presence of the CaO-SnO2 catalyst is carried out in a substrate (DME) medium and in its mixtures with CO2 under the supercritical conditions (100 atm, 250–300°C). At 255°C, the maximum conversion of DME (≈40% at the ratio of the yields of monoglim and diglim about 2: 1) is achieved at a 20-fold (by volume) dilution of DME with supercritical CO2.

Transformation of alkylbenzenes in an oxidizing medium on H-ZSM-5 catalyst under supercritical conditions

Reactions of the substituted benzenes toluene, p-xylene, fluorobenzene, phenol, cumene and styrene with nitrous oxide as an oxidant on H-ZSM-5 catalyst under supercritical conditions at 345–420°C and 70–150 atm were studied. It is shown that the products of disproportionation, isomerization and condensation that do not contain oxygen form predominantly. Only in the oxidation of toluene does the selectivity to the oxidation product (cresols) reach 35%. The yield of corresponding phenols in the oxidation of alkyl-, hydroxy- and fluorobenzenes is negligible. The double bond conjugated with the π-system of benzene rings (styrene), as well as the presence of branched alkyl substituents (in cumene) and hydroxyl-group (in phenol) hinder the formation of benzene ring oxidation products.