A. A. Ennan

Carbon-fibrous-material-supported base catalysts of ozone decomposition

It has been found that a carbon fibrous material characterized by the developed porous structure and predominance of basic surface groups, being a catalyst of low-temperature ozone decomposition, is also a suitable support for liquid-phase base (X−) catalysts (X−=OH−, Br− and I−). The data obtained in the reaction kinetics study at an initial ozone concentration ranging from 3.1×10−8 to 3.1×10−7 mol/l show that the support raises considerably the activity of the base catalysts. The catalytic activity decreases in the following series: I−>Br−>OH−.

Stabilization of silicon tetrafluoride by crown ether complexation. Crystal and molecular structure of the host:guest complex 1:1:2 between trans-tetrafluoro-bis(aqua) silicon, 18-crown-6 and water

Abstract The product of the interaction of silicon tetrafluoride with a solution of 18-crown-6 in hexane has been obtained. The composition and structure of the compound [(trans-SiF4.2H2O).18C6.2H2O] (complex I) have been determined by X-ray methods. The compound (I) is monoclinic, space group P21/a, a = 15.484(5), b = 9.651(3), c = 7.795(2) A, γ = 121.45(3)°, Z = 2 for the composition C12H32F4O10Si. In the crystal of (I) the polymer-like structure is realized where water and [trans-SiF4.2H2O] moieties are connected with the host and between each other by the system of O-H … O hydrogen bonds. O(H) … O distances are in the limits 2.60(1)–2.91(1) A. It was proved that in the process of crown ether complexation the hydratation of SiF4 occurred with the formation of a trans-octahedral [SiF4.2H2O] moiety, Si-F and Si-O distances are equal to 1.658(7) and 1.853(9) A, respectively. Between the individual chains there are only van der Waals interactions.

Phase Composition and Catalytic Activity of Nanostructured Materials Based on Solid Component of Welding Aerosol

The comparison of the phase compositions and catalytic properties of the solid components of welding aerosol (SCWAs) obtained as a result of metal welding by two types of electrodes, ANO-4 and TsL‑11 was made. Their phase compositions were investigated by X-ray diffraction phase analysis, IR spectroscopy, and pH-metry. The catalytic properties of SCWAs were studied in the low-temperature reaction of ozone decomposition. Both SCWA samples were found to purify the ozone-air mixtures (OAM) from ozone at its concentration of 1 mg/m3 to the levels below the maximum permissible concentration (MPCO3) however the protective time of SCWA-ANO-4 (50 h) was higher than that of SCWA-TsL-11 (3 h) because of the differences in their compositions

Schiff bases containing metal complexes anchored on aerosil as catalysts of low-temperature ozone decomposition

As found on the base of the data on kinetics of ozone decomposition by A-300 aerosil anchored metal complex compounds, ML2 (L—a Schiff base, namely azomethine of salicylic aldehyde and amine), the activity of the latter altered depending on a nature of metal as follows: Mn2+>Cu2+>Fe2+≊Zn2+. IR spectra and EDRS have proved the destruction of the ligand, L, by ozone. This was accompanied by formation of complexes inactive in the reaction.

Inclusion Complexes of Siliconhydrofluoric Acid Transformation Products with the Crown Ethers

Recently we have shown [1,2] that crown ethers and their aza-analogs are able to extract the distinctive species from the aqueous solution of siliconhydrofluoric acid which exists as an equilibrium mixture of the neutral and negatively charged compounds: [SiF42H2O], [SiF5H2O]- and SiF6 2-. The macrocycles below have been used for recognition of these entities in solution.

Nanostructured materials based on the solid component of welding aerosol as catalysts for low-temperature ozone decomposition

Samples of the solid component of welding aerosol (SCWA) obtained as a result of metal welding by two types of electrodes, ANO-4 and TsL-11, were characterized by elemental analysis, X-ray diffraction phase analysis, IR spectroscopy, and pH-metry. Both SCWA-ANO-4 and SCWA-TsL-11 samples purified the ozone-air mixture (OAM) with ozone concentration of 1.0 mg/m3 to the concentration values below 0.1 mg/m3 (maximum permissible ozone concentration, MPCO3).

Water vapor adsorption by nanostructured polyphase compositions based on the solid component of welding aerosol

The samples of the solid component of welding aerosols (SCWAs) formed in the electric arc plasma in the process of steel welding by electrodes of Ukrainian manufacture (ANO-4, ANO-21, UONI 13/55, and TsL-11,) differed in their chemical composition. The samples were characterized by X-ray phase analysis, IR spectroscopy, and water vapor ad/desorption. The results obtained allow suggesting the influence of a phase composition on the structural-adsorption properties of SCWAs.

СТАН І ПЕРСПЕКТИВИ РОЗРОБКИ НИЗЬКОТЕМПЕРАТУРНИХ КАТАЛІЗАТОРІВ ОКИСНЕННЯ МОНООКСИДУ ВУГЛЕЦЮ РЕСПІРАТОРНОГО ПРИЗНАЧЕННЯ. ІІІ. НАНЕСЕНІМЕТАЛОКОМПЛЕКСНІ КАТАЛІЗАТОРИ

Проаналізовані оригінальні, опубліковані в 2006-2012 роках роботи в області, розробки каталізаторів низькотемпературного (не вище 100 °С) окиснення монооксиду вуглецю. Серія статей містить у собі інформацію про металеві, оксидні і оксидно-металеві, а також нанесені металокомплексні (дана стаття) каталізатори. Проведене порівняння кращих закордонних і вітчизняних каталізаторів окиснення монооксиду вуглецю.

NMR Spectra of Guest–Host Complexes of Boron and Silicon Fluorides with Crown Ethers in Nonaqueous Solutions

Abstract19F, 11B, and 29Si NMR spectroscopy was used to examine the behavior of the guest–host complexes (BF3· H2O)2· 18-crown-6 · 2H2O, (BF3· H2O)2· DCH-6B, and (DCH-6A · H3O)SiF5in acetone (DCH-6B and DCH-6A are the cis-anti-cis- and cis-syn-cis-isomers of dicyclohexano-18-crown-6, respectively). It was shown that molecular boron fluoride complexes undergo partial solvolysis in acetone to yield BF3· acetone as the main product; the ionic pentafluorosilicate complex does not experience significant solvolysis transformations.