Home – Home – Jornals – Chemistry for Sustainable Development 2011 number 5

Preparative methods of the synthesis of organylsulphanyl(sulphonyl)acetic acids and their 2-hydroxyethylammonium salts developed by the authors are presented in this review. The latter salts represent a new class of pharmacologically active substances possessing antiaggregant, membrane-stabilizing, antioxidant, cytostatic, cardiotropic and hypocholesterolemic activity. Compounds with combined immunotropic and antitumour activity promising for the development of up-to-date remedies for treating immunodeficient, autoimmune, oncological and other diseases were found.

Denaturation of cellulosolytic enzymes produced by microorganisms Trichoderma viride in the presence of water was studied. Effective kinetic constants characterizing denaturation process were determined. It was shown that the enzymes in solution possess a narrow zone of stability, are stable at a temperature below 55 °С and rapidly gets denaturated when heated above 65 °С. In the dry state, the enzymes possess higher stability and get noticeably denaturated only at temperatures above 80 °С. The effective rate constant of denaturation is exponentially dependent on the concentration of water in the enzymatic preparation.

The interaction of amorphous silicon oxide (aerosil) with organic acids during mechanical activation in high-energy ball mill was studied by means of IR spectroscopy. It was demonstrated that monomer molecules of mono-, polyhydric and aromatic acids get bound with aerosil through the molecules of adsorbed water: aerosil–adsorbed water–acid. Water molecules form rather strong hydrogen bonds with the basic surface centres in aerosil and with hydroxyls of carboxylic groups in monomer molecules of acids. Both basic and acidic surface centres of the carrier take part in the mechanochemical interaction with aerosil.

UDC 541.18.053+543.42

Activated carbon was for the first time used as catalytic substrate in dechlorination process and a significant dechlorination (79 %) of most persistent 2,4,5–trichlorobiphenyl was achieved at 110 ºC in water/isopropanol solvent by applying reducing media. It was observed that carbon particles played a catalytic role to enhance the dechlorination process through substitution reactions and by suppressing further chlorination in reaction mixture. Dechlorination at the ortho position of biphenyl was clearly preceded through substitution reaction by hydroxyl and thiol ions. Moreover, in the absence of activated carbon, dechlorination was decreased and substituted products did not observed.

UDC 547

On the basis of the experimental data, a set of problems connected with the features of the crystallization of wavellite in the presence of additives is considered. It is established with the help of X-ray phase analysis that the precipitates formed under the conditions studied are presented by calcium oxalate monohydrate. The presence of magnesium ions, hydrophosphate, phosphate and sulphate ions in solution has an inhibiting action on the crystallization of calcium oxalate monohydrate. The hindering effect of the additive increases proportionally to an increase in the concentration of the additive. It was proved experimentally that amino acids have diverse effects on nucleation: some of them (glutamic acid, glycine, lysine etc.) inhibit the process, whereas the others (proline, alanine, valine etc.) act as catalysts; a number of amino acids (serine, phenylalanine) exhibit an insignificant effect on nucleation.

UDC 577.118.543.422

Alkaline hydrolyzates obtained from rice shuck processing were investigated. Results of the purification of alkaline hydrolyzates by means of coagulation, neutralization with the release of silicic acid, and sorption are presented. It is demonstrated that the purification methods used do not provide the requirements for preliminarily purified and fresh water for use in manufacturing unbleached cellulose with respect to the main hydrochemical parameters (coloration, mineralization, pH). It is established that alkaline hydrolyzates can be utilized with the formation of amorphous silicon dioxide which has a broad range of applications.

UDC 542.06:628.386:633.258

Data on the concentrations of hydrocarbons in the water phase and bottom settlings of sludge pits for the sludge pit technology of oil and gas well drilling are presented. Ionic and ultimate composition of the aqueous phase and bottom settlings were determined, as well as the concentration of radioactive elements. It was established that the high toxicity of sump hole content is mainly associated with the presence of high molecular fractions of hydrocarbons and the ions of sodium, potassium and chlorine. A substantial part of the sludge pit content is weakly toxic or non-toxic, it is confirmed by biotesting analysis. It is proposed to use the differentiated approach to the utilization of these wastes, in order to decrease material and energy expenses and increase the labour productivity.

UDC 504.064.47+504.054:622.816

Possibility of the low-temperature synthesis of zirconium dioxide nanopowder stabilized with yttrium (8 mol. %) from a mixture of hydrated zirconium oxynitride and yttrium carbonate mechanically activated in a continuous-type mill. It was shown that the powder formed even at 600 °С is easily moulded by dry pressing after disaggregation; its density after sintering is close to the theoretical value.

UDC 514.182+541.053

The composition of the soluble products of wheat straw delignification in the medium acetic acid–hydrogen peroxide–water–sulphuric acid catalyst was studied by means of elemental and chemical analysis, IR spectroscopy and gas chromatography-mass spectrometry. It was established that the vat residue formed in the regeneration of spent alkali liquor contains the products of polysaccharide degradation (4.7 rel. %), esters (19.9 rel. %) and sterols (37.2 rel. %). The acetic lignin precipitated from the alkali liquor contains a substantial amount of oxygen-containing functional groups. A promising character was demonstrated experimentally for the presently unclaimed bio-renewable resource such as wheat straw as a chemical raw material for obtaining sorbents and binders in the production of wood-based panels.

UDC 547.474:543.8:676.164

Selective sorption and desorption of the complex compounds of palladium from nitric solutions of silver on the ionites of different kinds was studied. Anionite VP-1P is recommended for the purification of electrolyte solutions from palladium in silver refining.

UDC 661.183: 669.23

Results of the investigation of reasons causing the destruction of molybdenum containers used for sintering the pellets of fuel uranium dioxide are reported. An effect of niobium ion implantation changing the microstructure and mechanical properties of molybdenum was investigated. It was demonstrated that niobium prevents the formation of carbide, nitride and oxide phases on the boundaries of molybdenum grains, causes the rate of metal grain growth in the course of recrystallization to decrease and stabilizes mechanical properties thus increasing the operational reliability by 30–60 %.

UDC 669.28:54

A new efficient broad spectrum agent comparable in efficiency with chemical fungicides was developed on the basis of the aqueous solution of the salts of fir extract with bisamine, with the addition of the salt of 2,4-dichlorophenoxyacetic acid with bisamine and the Usnea lichen extract. The agent suppresses the development of fungal diseases and increases the yield of spring wheat and potato.

UDC 547.99+632.934.1

A method is proposed for the sulfation of microcrystalline cellulose in the system N,N-dimethylformamide/chlorosulphonic acid with preliminary treatment of cellulose with ultrasound in an organic solvent. It is demonstrated that the treatment with ultrasound results in an increase in the reactivity of cellulose in the sulfation reaction as well as in occurring the sulfation in homogeneous medium. The action of ultrasound on microcrystalline cellulose is accompanied by a decrease in the polymerization level of the cellulose material and does not affect its crystallinity index. Water-soluble cellulose sulphates with the substitution level up to 1.5 were obtained using the method proposed.

UDC 541.64

The surface of oxides Mn₃O₄, Mn₂O₃ and MnO₂ subjected to mechanical activation with the help of high-intensity grinding was studied by means of X-ray photoelectron spectroscopy. It was discovered that the surface layers of all the three oxides were transformed during mechanical activation into Mn₂O₃ possessing increased chemical stability against environmental action. The results are due to the thermal effect and the catalytic action of extrinsic iron in the surface layer of Mn_mO_n particles.

UDC 546.713'712–31'713–31'714–31:544.3.032.2:543.428.4

The possibility of single-stage synthesis of isoprene from 1,3,5-trioxane and trimethylcarbinol in the presence of heterogeneous catalyst – strongly acidic macroporous cation-exchange resin – was established. The composition of the reaction mixture was determined by means of gas-liquid chromatography. Along with isoprene, unreacted trimethylcarbinol was detected, as well as by-products: unsaturated isoamylenic alcohols and 4,4-dimethyldioxane-1,3 – precursors of isoprene; the formation of an additional amount of isoprene during the decomposition of these compounds is possible. Optimal process conditions were chosen, providing the degree of trioxane conversion up to 99 %, selectivity of the process with respect to isoprene 65 %, and the yield of isoprene per transformed trioxane 64 %. In comparison with the existing two-stage methods of isoprene synthesis from the aqueous solution of formaldehyde and isobutylene, the proposed method allows one to decrease energy consumption and diminish the amount of waste water due to the “soft” technological conditions of the process.

UDC 54.05:542:547.315.2:504.064.043:620.9

Sorption of platinum chloro complexes from solutions with the help of oxidized carbon sorbents was studied. An effect of the oxygenated surface functional groups of oxidized carbon sorbents on their sorption capacity was studied using IR spectroscopy, pH-metry, titrimetry. Sorption isotherms for H₂PtCl₆ and Н₂PtCl₄ were obtained. It was established that the capacity of the sorbent with respect to H₂PtCl₆ increased by a factor of 2.4.

UDC 544.723: 546.26: 546.92