Synthesis and Properties of 2,2-Dichlorovinyl Trifluoromethyl Ketone

Highly reactive 2,2-dichlorovinyl trifluoromethyl ketone was synthesized. Its reactions with N,N-and N,S-nucleophiles gave 1,3-thiazine, pyrazole, and imidazole derivatives containing a trifluoromethyl substituent.     

Water effect on the physicochemical properties of oligomeric polysaccharide inulin

For oligomeric polysaccharide inulin from chicory roots, the heat capacity in the range of 80–330 K is measured, and values of standard enthalpy of combustion and formation were determined. Water concentration in inulin in the solution saturated at water melting temperature was determined by means of a calorimetric method from the melting enthalpy of water excess over its solubility in the oligosaccharide. Using the technique of differential thermal analysis, a temperature of relaxation transitions in inulin and an effect of water on these transitions are determined.     

New organosilicon derivatives of some analytical reagents: sorbents and metallochromic agents

A synthesis of organosilicon monomeric and polymeric derivatives of 1,4-phenylenediamine, 4-aminoantipyrine, and aniline, which are analytical agents possessing sorption properties, was accomplished. The synthesized organosilicon polymers were studied as sorbents of heavy metals Fe^III, Hg^II and noble metals Ag^I, Au^III, Rh^III, Pd^II, Pt^IV. Poly[(3-N-silsesquioxanylpropyl-4aminoantipyrine)] exhibited high sorption activity with respect to platinum group metals in comparison with poly[N,N´-bis(3-silsesquioxanylpropyl)-1,4-phenylenediamine]. The reaction of poly[(3-N-silsesquioxanylpropyl-4-aminoantipyrine)] practically with all the elements under study was accompanied by coloring. The starting monomer exhibited similar metallochromic properties.     

Evaporation from a surface and vapor flow through a plane channel into a vacuum

Two-dimensional steady rarefied-gas channel flow between two parallel walls, from an evaporating face to a perfectly absorbing plane end face, is studied. The vapor is considered to be a monatomic gas. The corresponding problem for the kinetic equation with collision integral in BGK form is formulated and solved numerically by two different finite-difference methods. Attention is focused on the calculation of the total gas flow rate through the channel cross-section. The structure of the gas channel flow as a function of the flow rarefaction, the channel length, and the ratio of the evaporation temperature to the wall temperature is studied.Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 150–158, January–February, 1996.     

Alkylation of 4,5-dihydro-1<Emphasis Type="Italic">H</Emphasis>-imidazole-2-thiol with iodomethylsilanes and -siloxanes

The alkylation of 4,5-dihydro-1H-imidazole-2-thiol with 1-iodomethyl(dimethyl)phenylsilane, 1-(iodomethyl)-1,1,3,3,3-pentamethyldisiloxane, and 1,3-bis(iodomethyl)-1,1,3,3-tetramethyldisiloxane involved iodine-catalyzed cleavage of the Si–C_sp ² and Si–O bonds with liberated (in situ) hydrogen iodide to afford 2-({[(4,5-dihydro-1H-imidazolium-2-ylsulfanyl)methyl]-1,1,3,3-tetramethyldisiloxanylmethyl}sulfanyl)-4,5-dihydro-1H-imidazolium di- and tetraiodides. Replacement of iodide ion in the products by triiodide gives new organosilicon ionic liquids with several charged fragments.     

Influence of heat treatment conditions on the physicochemical and catalytic properties of a chromium-containing catalyst for tetrachloroethylene hydrofluorination to pentafluoroethane

The physicochemical properties of coprecipitated 95% Cr₂O₃-5% Al₂O₃ oxide systems obtained by heat treatment of the precursor in nitrogen and air between 110 and 600°C and their influence on the catalytic activity in tetrachloroethylene hydrofluorination were studied by thermal and X-ray diffraction analyses, diffuse reflectance spectroscopy, and specific surface are measurements. The CrO_1.9 compounds are more active than CrO_1.5, but their preparation in the finely divided state is difficult because of the high exothermicity of the oxidation stage, which results in the decomposition of the oxides CrO_1.9 and CrO_1.5 followed by the crystallization and sintering of the decomposition products. Fine-powder and highly active chromium-containing oxides with CrO_1.9 stoichiometry can be obtained by two-stage heating of hydroxides first in nitrogen and then in air at comparatively low temperatures.     

Regularities of Lewis site formation upon the microwave irradiation of gibbsite-γ-Al(OH)3

Spatially separated Lewis acidic and basic sites can be formed upon the microwave irradiation of gibbsite. This is demonstrated by IR spectroscopy and indicates the possibility of the selective activation of chemical bonds of different nature within the initial crystals of Al³⁺ hydroxide. A scheme for the formation of spatially separated Lewis acidic and basic sites is proposed. It is shown that water as a product of the micro-wave activation of gibbsite is adsorbed on these Lewis acidic sites in molecular form (without subsequent dissociation) and is desorbed at calcination temperatures no higher than 100–110°C. During standard (contact) thermal treatment of Al³⁺ hydroxides and oxides, dehydroxylation and water removal take place at 350–550°C to form the acid-base pair-Al^δ+-O^δ?-. The microwave activation of gibbsite results in the formation of an amorphous component believed to consist of small -Al-O- complexes closely packed in the solid phase. It is established that the fraction of Al³⁺ atoms accessible for the low-temperature adsorption of CO in microwave-activated (for 10 min) gibbsite is 4.5 at % of the total number of Al³⁺ atoms present in the amorphous component of this material.     

Organylthiochloroacetylenes: IV. Reaction with Thiourea

Alkylthiochloroacetylenes react with thiourea in acetone to form S-(alkylthioethynyl)isothiuronium chlorides and N-[1-(alkylthio)ethylidene]thioureas; phenylthiochloroacetylene reacts with thiourea to give 4-(phenylthio)-2-imino-1,3(3H)-thiazole hydrochloride.