Home – Home – Jornals – Chemistry for Sustainable Development 2008 number 5

Alternative methods of the synthesis of pyrimidine-containing diamines are considered. These compounds are initial monomers for obtaining thermally stable high-module polymers (polyimides) which are used to develop promising materials for new technics. In accordance with the structure of diamines, the methods of their synthesis are systematized, their reactivity is evaluated. The problems concerning technological reasonableness, availability of the initial raw material and the possibility of scaling at separate stages of synthesis are assessed. The data on the thermal stability and deformation strength characteristics of pyrimidine-containing polyimides which are promising for the development of materials functioning within a broad range of extremal thermal conditions in a number of the areas of modern technologies are reported.

Thermal co-processing of hydrolytic lignin and heavy black oil within temperature range 350-415 °С at atmospheric pressure is investigated. The major products are represented by the liquid distillate products released from the reactor, and by the cracking residue in the reactor. Addition of lignin causes a substantial acceleration of the reactions of liquid-phase thermal cracking of black oil and increases the yield of distillate products. The ways of practical application of these products are proposed on the basis of the obtained data on the composition of the products of thermal co-processing of lignin and black oil.

Synthesis of microspheric zeolite sorbents based on the vitrocrystalline cenospheres of power engineering ashes was carried out for the first time, without any crystallization nuclei or structure-forming components. As a result of hydrothermal processing, the aluminosilicate material of cenosphere wall is transformed into low-module zeolites with the conservation of the morphology of initial particles. The final products are hollow spheres with a size of 80-200 m; their walls are composed fully or partially of the crystals of NaA, NaX and NaP1 zeolites.

Aerodynamic method followed by sieve analysis of the resulting fractions was applied to separate the concentrates of cenospheres of volatile ash from the combustion of coal of the Kuznetsk Basin at the Moscow Heat and Electric Power Plant (HEPP) No. 22, Belovo Hydroelectric Regional Power Plant, and some fractions of the concentrate of cenospheres obtained at the Novosibirsk Heat and Electric Power Plant No. 5. From the concentrate of the Moscow HEPP, 90 fractions with different particle sizes (70-250 m) and apparent (0.16-0.52 g/cm³) were separated. Independently of particle size, the apparent density of the fractions with the maximal yield is 0.33-0.35 g/cm³, while the ratio of the apparent wall thickness to the particle diameter is 0.042-0.043. The process of the aerodynamic separation of cenospheres of the concentrates from different sources is satisfactorily described by the theoretical dependencies for the escape of spherical particles; the deviations are first of all due to the non-spherical shape of cenospheres.

Under laboratory conditions, we determined the geochemical characteristics of the frozen soil of Yakutia, the activity of soil enzymes, physiological and biochemical characteristics of hornwort dandelion and relative stability of the genome of plant cells to the action of oil toxicants after the introduction of oil (0.07-1.95 vol. %) into soil samples. It is shown that the permissible level of pollution with oil for which soil is able to get recovered is ~1 g/kg of soil.

Results of the examination of the seeds of legumes growing under the conditions of moderate latitudes for the presence of reserve water-soluble polysaccharides galactomannanes are presented. A quantitative estimation of galactomannane content in the seeds of 45 species of 13 genera 7 tribes of the legume family is presented. For 23 species, a chemical characteristic was determined which shows the ratio of mannose to galactose monomers in galactomannane molecule. The results obtained in the investigation can be used for the search of home sources of plant hydrocolloids which would be of interest for various areas of science and technology.

It is shown that the main hindrance for the use of phosphohemihydrate, obtained during sulphuric treatment of the Khibiny apatite concentrate, in the production of construction materials is an increased content of phosphorus admixture in water-insoluble form. According to the previously developed technology of sulphuric extraction of the concentrate of lanthanoids from phosphohemihydrate, one achieves efficient leaching of water-insoluble phosphorus which gets accumulated in leaching solutions during their repeated use. It is proposed to remove phosphorus from sulphuric solutions in the form of hydrated titanylphosphate by means of precipitation with titanyl sulphate. The possibility to recover titanyl sulphate with the help of the alkaline treatment of hydrated titanylphosphate is demonstrated; the resulting product is a component of detergent Na₃PO₄ · 12H₂O. The versions of the sulphuric technology of phosphohemihydrate treatment excluding the formation of liquid wastes that require utilization are considered.

Synthesis of the hydrophilic derivatives of Осуществлен синтез гидрофильных производных 3-(4-hydroxyaryl)propyl series with sulphur-containing ionogenic fragments was carried out. The regularities of the changes of toxic effect of the synthesized compounds depending on their structure were investigated with respect to laboratory animals (mice) and bacterial cultures (Photobacterium phosphoreum).

For wastewater of the Angarst Electrolysis Chemical Plant as an example, the galvanochemical purification of the liquid radioactive wastes from the sulphuric scheme of uranium refining is investigated; its main regularities and features are determined.

We optimised the method of obtaining the monoammonium salt of glycyrrhizic acid (glycyram) from the roots of the Ural licorice ( Fisher) of Siberian populations. The method includes the following stages: extraction of the roots with a 0.5 % solution of NH₄OH, precipitation of the sum of acids with the help of concentrated H₂SO₄, subsequent re-extraction with a 1 % solution of H₂SO₄ in acetone, salting out the triammonium salt of glyccyrrhizic acid using a 25 % NH₄OH solution, transformation of this salt into the monoammonium salt (glycyram) by crystallization from glacial NH₄OH. Using this method, one may obtain the samples of glycyram with a purity of 85.2-87.5 % (according to the HPLC data). The glycyrrhizic acid content in the investigated samples of licorice roots is 2-4 %.

A resource-saving and ecologically safe technology of the purification of waste water of galvanic works from heavy metal ions is developed on the basis of the results of the experimental investigation of the equilibrium, kinetics and dynamics of adsorption, and mathematical modelling. A schematic diagram of the set-up for the purification of the wastewater from the galvanic works is proposed.

Using model solutions, we determined the conditions for the purification of wastewater containing fluorine in the concentration of 10 mg/in the form of complex anions AlF and/or FeF. Purification is performed with the help of cerium compounds. For real waste water of the plants situated in the Kola region (Apatit JSC, Lovozero GOK JSC), optimal modes of purification from fluorine impurity, using titanium compounds, down to the standard values of fluorine and sulphate ion concentrates established for drinking water were developed.

The effect of the preliminary chemical treatment on the process of mechanical powdering of the raw material is investigated. It is shown that the treatment of sawdust with the solutions of an acid, an alkaline or with enzymatic preparations results in the chemical modification of one of the components of the lignocarbohydrate matrix of sawdust (cellulose, hemicelluloses or lignins) and in the changes of the structure of wood. The effect of enzymatic hydrolysis on conversion degree and efficiency of powdering is investigated. It is shown that even a small degree of carbohydrate conversion (1-2 %) is sufficient for a decrease in the strength of wood structure by means of the enzymatic destruction of carbohydrates. The fraction of particles with a size within the range 19-25 Ојm increases approximately by a factor of 10 with the help of the method of preliminary chemical treatment of sawdust.

For the analysis of the samples of biological tissues (human myocardium and blood vessels) obtained by biopsy, the necessity arises to study the effect of the radiator density variations on the determination of chemical elements, since sample thickness varies depending on the type of tissue under investigation and sample mass (during sample preparation). Because of this, with the Bovine liver NIST 1577 standard sample, we studied the effect of the surface density of radiating device on the coefficients of relative sensitivity. The experiments were carried out at the station of elemental X-ray fluorescence analysis on the basis of the Siberian Centre for Synchrotron Radiation (Institute of Nuclear Physics, SB RAS, Novosibirsk). It was established that a change of the density of reference tablet density (at the excitation energy of 17 keV) during normalization of peak areas of the elements under determination to the area of Compton's peak has almost no effect on the results of analysis for the elements from Mn to Zn. For K, Ca, Fe and Rb, substantial differences of the coefficients of relative sensitivity (R_ist) are observed while the radiator density varies from 14.9 to 45.8 mg/cm².

Flavonoid content in the samples of plants of 15 species of Myosotis genus is examined. It is established that it is mainly 1.0-4.0 % in the plants of the investigated species; it is characterized by high variability for the samples collected in different regions. The variability of flavonoid content within the limits of one coenopopulation is low or medium. The species of Alpestres the section Myosotis of genus, especially M. asiatica , contain a large amount of flavonoids (up to 7.4 %) and are of interest for further investigation. The plants collected during the flowering period may be used as the sources of flavonoids.

In order to realize the strategy of the world community in the area of education for sustainable development, the D. I. Mendeleev Russian Chemical and Technological University and non-profit organization Love Russia  (Great Britain) for school pupils. In 2004-2007, practical ecological monitoring involved the pupils of more than 50 schools, boarding schools and social rehabilitation centres for juveniles; they carried out monitoring of water in the Kasimovo, Shilovo, Spassk Districts of the Ryazan Region and examined more than 150 objects along the passage 200 km wide along the Oka river. The results obtained in the investigation were considered as a part of ecological audit and discussed from the viewpoint of a practical example of the social responsibility of human beings for the processes that take part in the biosphere. A positive experience of the studies aimed at research of the problems of sustainable development and at carrying out ecological monitoring of wild nature allow us to propose these courses as a compulsory regional component of the school teaching process.