I. M. Borisov

Kinetics of oxidation of an arabinogalactan from larch (Larix sibirica L.) in an aqueous medium in the presence of hydrogen peroxide

The oxidation of an arabinogalactan in an aqueous medium under the action of hydrogen peroxide and dioxygen is accompanied by accumulation of carbonyl and carboxy groups in the oxidized polysaccharide macromolecules and derived oligomers. The addition of iron sulfate accelerates the radical oxidation of the biopolymer, while the addition of phenol inhibits the oxidation. The influence of the temperature and the initial H2O2 and arabinogalactan concentrations on the kinetics of the initial oxidation stage of the natural polysaccharide was studied.

Radical mechanism of pectin oxidation in aqueous solution

The kinetic features of functionalization of natural polysacharide, pectin, by liquid-phase oxidation were studied.

SYNTHESIS AND PHARMACOLOGICAL ACTIVITY OF THE OXIDIZED FRACTIONS OF ARABINOGALACTAN FROM SIBERIAN LARCH (Larix sibirica L.)

Aqueous solutions of arabinogalactan from Siberian larch (Larix sibirica L.) were subjected to oxidative destruction by a hydrogen peroxide – molecular oxygen system. The obtained high- and low-molecular-weight fractions of oxidation products were characterized by chemical and spectral methods and tested for pharmacological activity. The results of experiments on animals showed evidence for significant antiulcer and antiinflammatory properties of the preparations studied.

Arabinogalactan Poly- and Oligosaccharides Modified with 5-Aminosalicylic Acid

Arabinogalactan poly- and oligosaccharides from Siberian larch (Larix sibirica L.) were modified with 5-aminosalicylic acid. The chemical composition and certain physicochemical properties were studied. The optimal conditions for preparing the modified compounds were found. These compounds were demonstrated to possess anti-ulcer and anti-inflammatory activity in tests on experimental animals.

Chemiluminescence in the reaction of ozone with 1,3-dioxans in aqueous solutions

Chemiluminescence in the visible part of spectrum is found to assist the oxidation of substituted 1,3-dioxans by ozone in aqueous media. The kinetics of the chemiluminescence decay was studied in the temperature interval 323-353 K, and the activation parameters of this process were determined. A kinetic scheme is proposed to explain the results.

Enthalpies of addition of radicals to aldehydes, ketones, acids and esters

Enthalpies of the addition of radicals HO•, HO2•, CH3•, CH3O•, CH3O2• to the C=0 bond of model aldehydes, ketones, acids and esters have been calculated by thermodynamic and quantum chemical methods. It has been shown that the exothermic effect of these reactions decreases in the row HO•>CH3O•>CH3•>HOO•>CH3OO•.

Autocatalysis in oxidation of diesel fuel sulfides by hydrogen peroxide in the presence of molybdenum(VI) oxide

Oxidation of diesel fuel sulfides in the presence of molybdenum(VI) oxide was studied.

The interaction of poly- and oligosaccharides based on arabinogalactan with 5-aminosalicylic acid

The interaction of high-and low-molecular-weight arabinogalactans with 5-aminosalicylic acid was studied by spectral methods. It was found that the reaction of biopolymers with 5-aminosalicylic acid gave polymeric complex compounds of a 1 : 1 composition. The spectrophotometric data were used to calculate the stability constants of polysaccharide-pharmacon complexes. The influence of the structure of the reagents on their complex formation ability in aqueous solution is analyzed.

Enthalpies of elementary chain propagation steps in the oxidation of organic compounds

A calculation of the enthalpies of elementary steps of the intra- and intermolecular chain propagation for model oxidation reactions of ethers, esters, ketones and hydrocarbons has been carried out. The heats of the intermolecular and intramolecular transfer of free valence with participation of peroxy radicals and C−H bond of the oxygen-containing compounds are shown to be comparable.