G. F. Tereshchenko

Development and synthesis of bulk and membrane catalysts based on framework phosphates and molybdates

The scientific principles were formulated that underlie an integrated approach to development and synthesis of bulk and membrane catalysts for methanol transformation to dimethyl ether and hydrogen which are environmentally friendly fuels. The results were summarized for studies into relationships in formation of phosphates MZr2(PO4)3 (M = Na, K, Rb, Cs, Mg0.5, Ca0.5, Sr0.5, Ba0.5, Zr0.25), Cu0.5(1+y)FeyZr2−y(Po4)3, molybdate phosphates Na1−yZr2(Moo4)y(Po4)3−y, and molybdate Ni0.3Cr0.4Fe1.4(Moo4)3 with the desired structure and properties controllable by variation of their chemical composition and synthesis parameters. The surface characteristics and catalytic properties of the resulting systems and the yields of the target product formed from methanol transformations in inert and oxidizing atmospheres were analyzed in relation to the catalyst synthesis condition.

Catalytic properties of zirconium phosphate and double phosphates of zirconium and alkali metals with a NaZr2(PO4)3 structure

Zirconium orthophosphate Zr3(PO4)4 and double phosphates of zirconium and alkali metals AZr2(PO4)3 (A = Na, K, Rb, Cs) with a NaZr2(PO4)3 structure were synthesized and characterized by X-ray diffraction and electron microprobe analyses and capillary condensation of nitrogen. The catalytic properties of the phosphates in the dehydration of methanol were studied.

Structure of nanoporous carbon produced from titanium carbide and carbonitride

Scanning electron microscopy, X-ray diffraction and adsorption structural analyses, and helium pycnometry were used to study the structure of nanoporous carbon produced by chlorination of powdered titanium carbide and carbonitride and of titanium carbide synthesized by chemical-vapor deposition. The results obtained were used to make suggestions about the type of organization of the nanoporous structure of these materials. The evolution of the structure of nanoporous carbon was analyzed in relation to the chlorination temperature. The effect of the chlorination temperature on the structure of the nanoporous carbon obtained and on its pore volume was examined.

Optimization of Properties of Inorganic Catalytic Membranes Using Molecular Layering Nanotechnology

This survey is devoted to studying the process of modifying the surface of a porous matrix using the molecular layering method and the prospects of its application for controlling the structural, physical, and chemical characteristics of inorganic membranes. Experimental data on the application of molecular layering for the creation of membrane catalytic reactors with its given gas permeability, selectivity, and catalytic activity are discussed. It is demonstrated that such systems can be obtained by applying layers of certain thicknesses, structures, and chemical compositions on the inner surface of membrane pores in one technological cycle.

Dechlorination of persistent organic pollutants polychlorobiphenyls by catalytic carbonylation

A new approach to dechlorination of “dioxin-like” ecotoxicants, polychlorinated biphenyls, based on carbonylation, was suggested. The weakly reactive aryl halides are activated by effective catalytic systems based on epoxide-modified cobalt carbonyl in alcoholic alkali solutions.

Nanostructured catalytic membrane reactors of the new generation

Studied in this work were the industrially important processes (partial oxidation of methane, oxidation of methanol to formaldehyde, reduction of oxygen in aqueous media, oxidation of CO to CO2) involving the use of nanostructured catalytic membrane reactors of the new generation. The membrane reactors were prepared according to various methods: sol-gel, molecular layering, magnetron sputtering, chemical deposition, etc. Subject to study were also the structure of the catalytic membranes and the kinetics of the reactions occurring in the gaseous and liquid phases. It was demonstrated that the deposition of a nanostructured catalytic layer to nonselective porous membranes could give rise to, or enhance, the selectivity of both their gas permeability and catalytic activity. In the case of the application of hybrid membranes, an “asymmetry effect” was discovered and explained. Some of the membranes studied can be considered as specific nanoreactors.

Catalytic properties of sodium zirconium molybdate phosphates in methanol transformations

Molybdate phosphates Na1−yZr2(MoO4)y(PO4)3 − y (y = 0, 0.25, 0.5) having the NaZr2(PO4)3 structure were prepared by the sol-gel method. The catalytic properties of the molybdate phosphates in dehydration and dehydrogenation of methanol in inert and oxidizing atmospheres were studied.

Phosphates M 0.5(1 + x) 2+ Cr x Ti2 − x (PO4)3: Synthesis, structure, and catalytic properties

Complex phosphates of titanium, chromium, and metals(2+) of the general formula M0.5(1 + x)CrxTi2 − x(PO4)3 (M = Mg, Ca, Mn, Ni, Sr, Ba, and Pb) were synthesized. Their phase formation was studied by means of X-ray powder diffraction, electron probe microanalysis, differential thermal analysis, and IR spectroscopy. Individual phases and solid solutions crystallizing in kosnarite and langbeinite structure types were identified; their crystallographic parameters were calculated. The catalytic properties of phosphates Ca0.5(1 + x)CrxTi2 − x(PO4)3 in methanol conversion were studied.

Structural, chemical, and dynamic characteristics of ceramic membranes modified with self-organized supramolecular silicon oxide systems

The changes in structural characteristics, chemical composition, and gas permeability of the modified ceramic asymmetric tubular membranes were studied. The membranes were tested in permeability and selectivity of two gaseous mixtures (H/He and H/Ar). The structure of the modified coating was examined by X-ray powder diffraction and by transmission and scanning electron microscopies.

Electrochemical synthesis of perfluoropolyethers by the Kolbe method

Electrochemical dimerization of hexafluoropropylene oxide dimer and trimer acids on SU-2000 glassy carbon, bulk platinum, and SU-2000 electrodes modified with platinum-group metals in acetonitrile in the presence of water was studied at various concentrations of the starting substance and different degrees of neutralization of the starting acid. Also, the possibility was examined of obtaining some perfluoropolyethers in a single process by cross-condensation of several starting perfluorocarboxylic acids, followed by separation of the products by physicochemical methods.