Home – Home – Jornals – Chemistry for Sustainable Development 2003 number 2

Halogenated non-terpenic C₁₅-acetogenins of sea organisms make up a large group of natural compounds. Structures of more than 130 compounds are considered and data on their biological activity are presented.

The review is dedicated to a group of natural compounds of a new type

The organochlorine pesticides (OCPs) content in bottom sediments of main tributaries of the Lake Baikal was studied. Experimental data on the presence of hexachlorobenzene, DDT and its metabolites and hexachlorocyclohexane (HCH) isomers in sediments allowed estimating pathways of OCPs input to the Baikal basin.

A two-stage method of converting aromatic nitro compounds into luminophors is proposed. It includes catalytic reduction of the nitro aromatic compound by molecular hydrogen followed by the interaction of the formed aromatic amine with a fluorogenic reagent (fluorescamine, ortho-phthalaldehyde). Efficient reduction is provided by using palladium catalysts on supports with developed surface, such as barium sulphate, C₆₀ fullerene, and microcapillary glass plates. Luminescence of the final products is observed in the regions l = 490

The reaction of 2,6-di-tert-butylphenol with allyl alcohol resulting in the formation of 4-(3-hydroxypropyl)-2,6-di-tert-butylphenol is implemented on industrial scale. Condensation of the product with phthalic anhydride leads to the formation of the corresponding diphthalate, which is the final commercial product. The stability of operation at all technological stages was achieved in course of industrial practice.

The structure transformations of the wood under mechanochemical treatment in vibratory centrifugal, planetary, and ball mills are investigated by means of electron microscopy, X-ray diffraction, thermomechanical spectroscopy. Specific surface of the samples is estimated. Features of the changes in wood properties under grinding in these types of mills are established. Under wood treatment in vibratory centrifugal and planetary mills, no complete amorphization of the structure of wood matrix occurs; quite contrary, some ordering is observed.

The synthesis of bismuth (III) oxohydroxostearate through the interaction of stearic acid with bismuth-containing perchlorate or nitrate solutions is investigated by means of X-ray phase analysis, thermogravimetry, electron microscopy, IR spectroscopy and chemical analysis. The conditions for the formation of bismuth stearate of Bi₆O₄(OH)₄R₆ composition (where R is stearate anion) are determined. Reasonability of obtaining highly pure bismuth stearate from metal bismuth is demonstrated; the latter is preliminarily oxidized with oxygen of the air, the resulting Bi₂O₃ is dissolved in nitric acid (1 : 1); bismuth is purified from extrinsic metals by its precipitation in the form of oxohydroxostearate, which is formed on adding bismuth nitrate solution to sodium stearate solution at the temperature of (80

Reactions of CdX (X = Br, I) with MBH₄ (M = Li, Na, K) under mechanical activation (MA) of the mixtures of crystalline compounds in vacuum vibratory mill are investigated. It is discovered that the reactions are accompanied by the formation of B₂H₆; its yield depends on the nature of CdX₂, MBH₄and correlates with the calculated values. It is shown that the mechanochemical synthesis of B₂H₆ depends on temperature within the range 50_120

The possibility to apply time-resolved fluorescence spectroscopy to the analysis of mixtures of aromatic amines or nitro compounds after their preliminary reduction to amines is demonstrated.

A comparative analysis of biogenous and synthetic carbonate hydroxylapatite of various degree of crystallinity has been carried out. The analysis of chemical composition of enamel and dentine was carried out on an X-ray microanalyzer, that of the synthetic product on an X-ray fluorescence spectrometer. Crystallochemical characteristics were studied by X-ray diffractometry and molecular spectroscopy. Identity of structural characteristics and of the chemical composition of the specimens studied was demonstrated. Toxicological, mutagenic properties and histocompatibility of the synthetic apatite were studied. The material obtained was used for treatment of patients with defects of bone tissue.

The processes involved in treatment and processing of copper and nickel ores with the use of phosphoric acid solutions are investigated, as well as processes of precipitation of platinum metals with thiocarbamide and sorption of nickel and cobalt from phosphoric solutions. A technology is proposed for co-processing of copper and nickel ores from Noril'sk deposits and the apatites from Maymecha-Kotuy province. Advantages of this technology are: isolation of all valuable components from raw material in the form of high-quality primary concentrates, decrease in the amount of recycling products due to simplification of the technology, high coefficient of multipurpose utilization of raw material, which provides manufacture of additional products, absence of the necessity for expenses to build tailing and cake dumps, sulphur utilization in Clause process, which provides a decrease in environmental hazard, simplicity of instrumentation, simultaneous production of phosphoric fertilizers for the needs of agriculture in Siberia.

Results of experiments on low-temperature pyrolysis of sapropelite coals that can be used to develop scientific foundations of technology for processing of sapropelite fossil fuels in order to transform them into synthetic fuel and raw materials for chemical industry are described and discussed. Pyrolysis products have been obtained from sapropelite coals of various deposits with different degree of catagenetic maturity of the organic matter. The yield of liquid products for some coal samples was as high as 60 % (by mass). Liquid pyrolysis products have been studied ¹H and ¹³C NMR spectroscopy and separated into fractions column chromatography and distillation. According to chromato-mass spectrometry the obtained fractions are complex mixture of hundreds of compounds. The bulk of pyrogenetic products of the samples consists of alkanes and alkenes of normal structure. The high yield of liquid pyrolysis products obtained from sapropelite coals permits considering them as a promising raw material for obtaining artificial liquid fuels. Similarly to the traditional use of petroleum, processing of these products with a wide use of fractionation and hydrogenization is necessary.

The operation of gas diffusion hydrophobized electrodes (HPE) made of black mixtures (hydrophobic soot A437-E and hydrophilic ones P702 and P805-E) during the electrosynthesis of hydrogen peroxide from oxygen is investigated. Changes in the characteristic length of electrode in the process under investigation depending on the highly develop three-phase boundary electrolyte

The effect of components ratio in the mixture composed of atactic polypropylene and hydrolytic lignin on the yield of products and composition of the light (b.p. < 180

The investigation of gypsum (calcium sulphate dihydrate), obtained in course of serpentinite processing, is performed. It is shown that the product is characterized by high ecological purity and meets the demands of the All-Union State Standard (GOST) to the 1st-rate gypsum. The gypsum binder made of the gypsum obtained from serpentinite corresponds to rapidly and normally hardening grades G-2