Home – Home – Jornals – Chemistry for Sustainable Development 2010 number 5

p-Thyrozole is characterized as a prophylactic and medicinal agent for veterinary and medicine. Natural sources and methods of obtaining synthetic p-thyrozole are considered. Data on its toxicity, pharmacological activity and physicochemical properties are reported.

Regeneration of cadmium deposited by electrolysis on carbon fibrous electrodes during processing ammine rinsing solutions from cadmium plating due to the performance of the short-circuited electrochemical system or anodic dissolution is investigated. Changes of the properties of carbon fibrous electrodes during their cyclic use in the processes of cadmium electrodeposition-dissolution and the possibility of their repeated use were examined.

Results of the investigation of composition and content of the flavonol complex in Aconogonon alpinum (All.) Schur which is widespread in the Altay are reported. The above-ground part of the plants contains glycosides: astragalin, quercetrin, avicularin, hyperoside, quercetin-3,7-diglucoside, rutin, myricitrin, and aglycones: kaempferol, quercetin and myricetin. The concentration and qualitative composition of flavonols in the plants collected in the phase of mass blooming in the Ust-Kan District of the Republic of Altay (meadow steppe, 293 km along the road to Tuekta village) were investigated by means of HPLC. Due to the high content of flavonols (up to 10.35 %) and the rich qualitative composition, A. alpinum can be used as a source of these very valuable compounds with high biological activity and low toxicity.

Regio- and diastereoselectivity of 1,3-dipolar cycloaddition of 4-methoxybenzonitriloxide to α,β-unsaturated esters of α-D-xylo-pentadialdo-1,4-furanose depending on the geometry of the double bond and the method of generation of nitriloxide is studied.

Physicochemical and biological properties of the composite calcium phosphate chitosan coating are investigated. It is shown that the introduction of chitosan increases the concentration of the amorphous phase composed of nanosized particles; an increase in its concentration leads to changes of the thickness and roughness of the coating. It was revealed that during obtaining the composite coating by means of electrochemical deposition, chitosan and Са-Р get deposited onto the surface of titanium substrate interchanging chaotically and mutually supplementing each other, with the formation of a net structure. The СаР/Ch composites modulate in vitro and in vivo the functional activity and differentiation of stromal stem cells in the osteogenic direction, due to which they are promising in the aspect of developing new class of implants for orthopaedics and traumatology.

Complex processing of the oil-containing flotation leucoxene concentrate accompanied by recoating the organic fraction was investigated. In order to obtain the pigment titanium dioxide concentrate from the leucoxene concentrate, reducing roasting with petroleum coke was used, at the temperature of 1100-1150 °C.

Results are presented concerning the studies on the physicochemical properties of a bacterial cellulose film, obtained by culturing the symbiotic acetic-acid bacteria Acetobacter xylinum and the yeast of genus Brettanomyces, Zygosaccharomyces, Saccharomyces. A block diagram is presented for the production and purification of the cellulose from impurities. High consumer properties of bacterial cellulose are demonstrated. Sorption properties were determined with respect to ε-aminocaproic acid and sea buckthorn oil. Prospects were estimated concerning the application of bacterial cellulose gel films in order to create transdermal therapeutic systems.

As the result of the aerodynamic separation of non-magnetic cenosphere fraction, we obtained and characterized narrow homogeneous fractions differing in chemical composition, bulk density (0.195-0.396 g/cm³), average diameter (133-153 μm), thickness (3.1-7.6 μm) and the porosity of globule shell. Regularities in the relationship between the composition and morphology of the globules were established. After processing the product of aerodynamic separation by a reagent based on hydrofluoric acid we obtained a microspherical carrier with available internal volume and pore size ranging within 1-5 μm. Basing on this, we obtained a microspherical adsorbent with an active component triisobutyl phosphine sulphide for selective palladium extraction within a wide range of concentrations (3.6-360 mg/L) from corrosive media.

Role of mineral suspended particles and the intensity of plankton reproduction in the sedimentation processes of the removal of Cu, Pb and Cd from water in a polluted water reservoir were studied by means of mesomodelling. Under the action of metals, the structure of the natural phytoplankton community gets rearranged, which leads to gradual increase in the total number of organisms and an increase in their fraction in settling sediments. This is accompanied by an increase in the concentrations of metals in sediments, likely due to the higher biosorption in comparison with metal sorption on mineral suspended particles.

A systematic study was performed concerning decomposition kinetics for 3-nitrophenol, 4-nitrophenol, 2,4-dinitrophenol, 2,6-dinitrophenol effected by hydrogen peroxide in the presence of iron (II) and (III). Relative reactivity was established for the mentioned dinitrophenols during oxidative degradation.

Complete chemical composition of surface water, drainage solutions and the substance carried off in the aureole of scattering at the Urskoye tailing dump was investigated. The regularities of the migration of heavy metals were revealed in connection with the increasing distance from the pollution source. It was established that storing high-sulphide waste material in non-fixed piles resulted in dissemination of the material and therefore caused the formation of the aureole of scattering. It was discovered that the water of a natural brook draining the waste material get mineralized and acidified. In the lower part of the dump, the acid water of the brook contacts the peat material of a marsh-field. At the site where the brook flows into the Ur River (a tributary of the Inya River), the acidic Fe-Al sulphate water of the brook get mixed with the fresh Са-Mg hydrocarbonate water of the river. As a consequence, the metal content of the river water increases sharply, while the recovery of water composition in the Ur River down to the background level occurs at a distance of 5 km from the mouth of the drainage brook. It was established that as a result of the gravitation differentiation the substance near the dump is enriched with larger and heavier fractions, while light-weighed finer particles are carried off along the ravine. The maximal Fe and Cu content in the carried-off waste material is confined with the sulphide material. Uliginous substance interstratified with organic residues and is characterized by increased Zn and Pb content. It was discovered that the element content of buried peat is comparable with their concentrations in the waste material overlapping the peat.

Highly efficient catalysts based on intermetallic compound Ni3Al obtained by self-propagating high temperature synthesis were investigated. Catalytic tests in the course of carbon dioxide based methane reforming were carried out at atmospheric pressure within the temperature range of 600-950 °C. It was established that the activity of intermetallic compounds increases with increasing the nickel content in the system. The methods of SEM, EDX, HRTEM, EDAX, XRD, and DSC proved that exposing high temperature values and severe redox medium in the course of the reaction results in an insignificant destruction of catalysts' initial structure with the formation of carbon deposits with ordered structure and fibrous morphology, which does not prevent the methane-to-synthesis-gas conversion reaction to occur.

Formaldehyde electrocatalytic oxidation of was studied on a copper-containing catalyst placed in an electrochemical cell. The effect of catalyst on the  formaldehyde oxidation when changing parameters such as solution flow rate through the reactor, wherein the catalyst was placed, power density supplied and interelectrode spacing.

Results are presented concerning the cause of destructing the molybdenum containers those are used in sintering the pellets of fuel uranium dioxide. An effect of niobium ion implantation on changing the microstructure and mechanical properties of molybdenum was studied. It was demonstrated that niobium prevents the formation of carbide, nitride and oxide phases near molybdenum grain boundaries, thereby causing an increase in the operational reliability.

Mechanochemical treatment of pyrocatechin and natural gallocatechins with amorphous silicon dioxide leads to an increase in the rate of silicon dioxide dissolution as a result of the formation of chelate complexes. On the basis of model systems, we propose a mechanism of the interaction of polyphenols with silicon dioxide including the interaction of hydroxyl groups on the surface of silica with polyphenols and the formation of surface complexes. Starting from the proposed mechanism, we developed a procedure for the directed hydroxylation of the surface. Its application causes an increase in the process efficiency.