Home – Home – Jornals – Chemistry for Sustainable Development 2009 number 5

Features of the physicochemical properties of uranium oxide are considered in the review. Chemical processes that involve the catalysts containing the compounds of depleted uranium are considered. The data published within the years 1964 to 2009 are included in the review.

Thermooxidative destruction and combustion in the flare of fine coal obtained by mechanochemical treatment in high-energy activator mills of different types are studied. Activation in mills leads to a decrease in particle size, enhancement of the reactivity of fine coal, and accelerates coal combustion in flare. The effect of combustion acceleration is essentially dependent on the type of mechanical treatment. In the case of the close particle size distribution, activation under the free shock conditions is more efficient: the flare turns out to be close to the flare of gas fuel. In comparison with coal obtained under the conditions of restricted shock, fine coal obtained under free shock conditions burnt immediately after preparation is characterized by higher (by 20 %) rate of oxidation under non-isothermal conditions, while the maximal process temperature changes from 560 to 780 ^оC. The effect has a reversible character; it remains essential for the interaction of coal particles with oxygen of the air under non-isothermal conditions for 2 h.

Changes of the supramolecular structure of the yeast cell wall under the action of mechanical activation are studied. It is established that the reactivity of the polysaccharides of cell wall towards the subsequent enzymatic hydrolysis increases substantially. A new method to obtain biologically active mannanooligosaccharides is proposed; this method is based on the mechanical activation of enzymatic hydrolysis of the components comprising the supramolecular structure of cell wall, followed by extraction of the target components.

The substance of stored wastes from sulphide ore dressing (dumps of clinker from the Belovo zinc plant, tailings of the Komsomolskoye gold extracting plant and Salagaevo ravine of the Salair Ore Mining and Processing Plant) and recrements planned for storing during processing the ore bodies of the Vedugino gold deposit were investigated. Field experiments on draining the matter of the objects with natural neutral water were carried out. The amount of sulphate ions and metal ions passing into solution was estimated. A connection between the experimental data of physicochemical analyses (pH of the paste of the substance, acid-producing and acid-neutralizing potentials) and chemical composition (total concentration of the ions of major technogenic elements: iron, zinc, copper, cadmium, lead) in drainage flow is demonstrated.

Rickardine С (1), natural 18-membered macrocyclic bisbibenzyl and inhibitor of NO synthase, was extracted by us from Primula macrocalyx Bge. A series of modifications of compound 1 by interaction with various halogenides and anhydrides of acids in the presence of bases, resulting in the formation of ethers and esters of rickardine C, was obtained (4-15). The structure of the latter compounds was established using spectral methods and mass spectrometry.

Seasonal dynamics of the accumulation of the major component of Primula macrocalyx Bge. - bisbibenzyl rickardine C (1), inhibitor of inducible NO synthase, was investigated. Seven introduced populations of this species were studied. A wild-growing population of P. macrocalyx served as a reference. It is demonstrated that it is reasonable to pick the plant raw material for the purpose of extraction of bisbibenzyl (1) after blooming, at the bearing phase. In addition, during the investigation, 3′,4′,5′-trimethoxyflavone (2) and perrhottetine E (3) were isolated from the acetone extract of P. macrocalyx.

Data on the mechanochemical synthesis of single-phase hydroxyapatite (HA) with the substitutiosn of phosphate for silicate ion, having the composition Ca₁₀(PO₄)_4.28(SiO₄)_1.72(OH)_0.28 for use as the target material for hgih0-frequency magnetron sputtering are presented. The elemental composition of the coating deposited on titanium substrates of the Ti6Al4V type used as medical implants is similar tot he element composition of the target. According to the data of IR spectroscopy, the ions are built into the lattice of the coating which has the HA structure according to the XPA data. The
Si-HA coating has probably the amorphous and crystalline structure.

Structural and chemical changes in the minerals during fine grinding are investigated. It is established that mechanochemical treatment causes leveling of surface properties and worsening of the separation of mineral substances using the floatation method. The problem of decreasing defect formation and structure amorphization during fine grinding of geomaterials is formulated. For tinstone and copper-nickel ores as examples, the effect of surfactants on structural and chemical properties of the minerals was investigated; the possibility to slow down defect generation and amorphization decrease is demonstrated.

Reaction of the catalytic hydrodeoxygenation of biodiesel - a mixture of methyl esters of fatty acids - is investigated for the purpose of obtaining linear alkanes. Precious metals (Ru, Rh, Pd, Ir, Pt) deposited on the binary oxide system CeO₂-ZrO₂ were used as catalysts. It is shown that these catalysts allow one to carry out efficient deoxygenation of methyl esters of fatty acids under hydrogen pressure 0.5 MPa within a broad temperature range (300-380 ^оC) resulting mainly in heptadecane (С₁₇Н₃₆). However, only in the presence of Rh and Ru catalysts the yield of alkanes is quantitative. The process of obtaining linear alkanes of the С₁₄-С₁₈ series using this method is positioned as a stage of production of high-quality kerosene fuel of plant origin.

Oxidation of iron in the underground low mineralized underground cold water of the Tyumen North by ecologically safe oxidizing agent - hydrogen peroxide - is investigated. The dependences of the residual iron content on the concentration and specific dose of the oxidizer for the process performed in a closed volume and with the sand filter loaded are obtained. The results of the investigation were used in designing and building the station of underground water conditioning with a productivity of 50 thousand m³/day in Novy Urengoy.

Antimycotic activity of monoterpenoids of menthane series and their thio derivatives obtained via the reaction of the corresponding monoterpenoids with thiols in the presence of Lewis acids was investigated. On the basis of (+)-1,2-oxide of limonene and methyl ester of mercaptoacetic acid in the presence of sodium methylate, an active antimycotic of the broad range of action was synthesized. The data on the toxicity of some monoterpenoids are reported.