Chemical modification of polyvinyl chloride with thiourea

Russian Chemical Bulletin - The quasi-homogeneous (“synthesis in gel”) conditions for functionalization of polyvinyl chloride (PVC) with thiourea were experimentally selected. It was...     

The Peculiarities of Extraction of Vanadium(V) by Aminophenols from Sulfuric Acid Solutions

Journal of Solution Chemistry - The effects on the extraction of Vanadium(V) by N-(2-hydroxy-5-nonylbenzyl)-β,β-dihydroxyethylamine of different factors, including pH of the medium,...     

Modeling of 1,2,4,5-tetrazine complexes with organic amines

Tetrazine complexes with organic ligands have been modeled. The composition and structure of the model complexes agree with experimental data. The structure and nature of the complexes affect a number of chemical reactions of 1,2,4,5-tetrazines with organic amines. It is shown that the possibility and route of nucleophilic substitution in the 3 and 6 positions of the tetrazine ring are provided by amine localization in the tetrazine complex and also by the orbital characteristics of the reagents. The route and possibility of cycloaddition reactions for tetrazines are dictated by the ability of the latter to form π-complexes with reagents and by the orbital characteristics of the complexes. The route of the cycloaddition reaction is also affected by the solvent.     

High-performance liquid chromatography coupled to mass spectrometry for studying new pharmaceutical entities

The review covers the aspects of the use of high-performance liquid chromatography coupled to mass spectrometry for studying new pharmaceutical entities. Attention is paid mainly to pharmacokinetic investigations. Different methods of sample preparation and approaches to minimize the duration of the analysis are discussed.     

Reduction of Carbonyl Compounds with Polyethylsiloxane in the Presence of Titanium Compounds

Reduction of carbonyl compounds with polyethylsiloxane in the presence of titanium alkoxides gives the corresponding alcohols in high yields.     

Chemical properties of N-2-Sulfoethylchitosan with a medium degree of substitution

A method was developed for the preparation of N-2-sulfoethylchitosan (SECH) via synthesis in a gel with the use of the reaction of chitosan and sodium 2-bromoethanesulfonate. This method makes it possible to conduct a polymer-like transformation without any acid or base. The structures of the obtained polymers were confirmed via IR and ¹H NMR spectroscopy. The study of the sorption of Ag⁺, Cu²⁺, Zn²⁺, Ni²⁺, Co²⁺, Cd²⁺, Pb²⁺, Mn²⁺, Mg²⁺, Ca²⁺, Sr²⁺, and Ba²⁺ ions that were crosslinked by SECH during their joint presence in an ammonia-acetate buffer solution showed high values of selectivity in relation to those of silver(I) and copper(II). The selectivity of the sorption of silver(I) ions with respect to copper(II) ions increased with an increase in the degree of substitution of SECH.     

A new approach to preparation of granulated materials based on chitosan and its imidazole derivative

A new approach to preparation of granulated materials based on chitosan and N-(5-methyl-4-imidazolyl)- methyl chitosan was developed. The procedure is simple and efficient and involves the use of glutaraldehyde as cross-linking agent without using precipitants. The composition and structural features of the materials obtained were determined by elemental analysis and Fourier IR spectroscopy. The dependence of the degree of material swelling on the degree of functionalization with glutaraldehyde was determined. The polymer granules were used as support for Pd0-containing catalysts for reduction of organic compounds.     

Determination of Interproton Distances in Water Molecules of Crystalline Hydrates by IRS Data

The knowledge of interproton distances R_H-H in water molecules is necessary in determining the positions of hydrogen atoms, and in establishing the geometry of hydrogen bonds in crystalline hydrates (v., for instance^I), R_H-H is usually found from the data yielded by the methods of neutrography and proton magnetic resonance. An attempt has been made in the present work to employ the IRS technique to estimate the values of R_H-H.     

A carbon-silica composite material based on powdered cellulose: Synthesis and properties

A procedure was developed for preparing a carbon-silica composite by thermolysis of powdered cellulose in the presence of tetraethoxysilane. The resulting composite was studied in model processes of trimethylhydroquinone oxidation and hydrogen peroxide decomposition.