Alexander A. Greish

Electrodeposition of rare earth metals Y, Gd, Yb in ionic liquids

The possibility of yttrium, gadolinium, and ytterbium electrodeposition from solutions of their triflates in different ionic liquids at 100°C was investigated. It was shown that these metals could be deposited on the cathode from electrolytes based on ionic liquids with quaternary ammonium cations, and these metals do not deposit from 1-butyl-2,3-dimethylimidazolium triflate. It was established that, in the case of butyltrimethylamonium triflate usage, metal deposition occurs on a copper electrode, and it does not occur on a platinum electrode, and in 1-butyl-1-methylpirrolidinium triflate, the reduction process is possible on both electrodes. Yb3+ reduction occurs step by step via Yb2+ formation. It was shown that the limiting stage of the cathode process is adsorption of a metal cation on the electrode.

Metathesis of hex-1-ene in ionic liquids catalyzed by WCl6

Metathesis of hex-1-ene in ionic liquids catalyzed by WCl6 was studied. The metathesis is preceded by isomerization of hex-1-ene to hex-2-ene, from which the main reaction product, viz., oct-4-ene, is derived. The WCl6-1-butyl-3-methylimidazolium tetrafluoroborate (BMIM·BF4) system efficiently catalyzes metathesis of linear olefin, the ionic liquid serving as the reaction medium by forming a stable homogeneous catalytic system with WCl6. The yields of the metathesis products increase with increasing reaction temperature. The addition of tin-containing promoters leads to a substantial increase in the reaction rate. In the WCl6-BMIM·BF4-SnBu4 system, the selectivity of the formation of oct-4-ene is significantly enhanced.

Spectral studies of catalysts of oxidative dehydrogenation of dimethyl ether to dimethoxyethane

Spectral methods (diffuse reflectance infrared Fourier transform spectroscopy, EPR) are used to study the adsorption of dimethyl ether and oxygen on a catalyst of oxidative dehydrogenation of dimethyl ether to dimethoxyethane. The formation of O2− superoxide paramagnetic species is revealed. A mechanism of the formation of dimethoxyethane is proposed.

Effective Purification of Water from Iron Ions and Potentially Pathogenic Microorganisms Using a Montmorillonite Composite Sorbent

The use of the developed composite sorbent based on the plant wastes (sunflower seed husks) and montmorillonite clay was shown to be highly effective for water purification from iron ions and potentially pathogenic microorganisms. It was shown experimentally that the developed composite sorbent at concentrations of up to 50 mg/L is capable of purifying water from iron ions under static and dynamic conditions. When a suspension of Escherichia coli was filtered at a rate of 10 mL/min, 1 g of the composite sorbent adsorbed 556 million E. coli colony-forming units (CFUs), showing that the sorbent is 1.7 times more effective than the complex sorbent of the replaceable Barrier-4 filter cartridge.

Deep oxidation of methane on granulated and monolith copper—manganese oxide catalysts

Deep oxidation of methane on the granulated Cu—Mn-mixed oxide catalyst and metallic monolith catalysts coated with the same oxide was studied. The experimental kinetic curves for both monolith and granulated catalysts are satisfactorily described by the first-order rate law. The values of activation energies, reaction rate constants, and feed flow rates for the specified conversion almost coincide for both types of the catalysts. The data obtained confirm the possibility of a quantitative comparison of the activities of the granulated and monolith catalysts. The activity of the monoliths is proportional to the concentration of the active component.