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Sources of organochlorine waste (OCW) generation in the production of vinyl chloride, their toxicity and impact on the environment were analyzed. A comparative analysis of methods of waste disposal was performed. It was established that the method of thermal decontamination has gained the widest application. Methods of identification of organochlorine compounds and methods of separation and concentration of substances were considered. It was determined that one of the effective methods of their extraction is liquid extraction using oxalic and hydrochloric acids as extractants. As a result of the analysis of the composition of insoluble compounds in the cubic residues of the vinyl chloride rectification stage before submitting them to incineration, the presence of two following compounds was established: Fe2O3 and Fe3O4 with a predominant content of the Fe3O4 phase. The rational conditions for the extraction of iron compounds from OCW have been established: the type of extractant (chloric acid), the ratio of OCW:extractant; number of extraction cycles, and temperature. The rational concentration of hydrochloric acid as an extractant is 1%. Reduction of the content of iron compounds in OCW will contribute to increasing the operational life of the incineration plant from 20 days to three or more months. [ABSTRACT FROM AUTHOR]

Background. Agriculture is considered not only from the position of providing food products, but also as a promising source of strengthening the export potential of the republic. With the reduction of areas under cotton and grain, mineral fertilizers, stimulants, defoliants and other plant protection products are required. Purpose: substantiation of obtaining drugs with nutritional and physiologically active properties by studying the interaction and rheological properties of the systems of dihydrate oxalic acid and urea Methodology. The solubility was determined using a viscometer VPZh, pH - on a FE 20 METTLER TOLEDO pH meter, light refractive index - on a PAL-BX/RI refractometer. Originality. The interaction of two-water oxalic acid and urea was studied, and on their basis a diagram of the solubility of systems and "composition-properties" was constructed. Findings. Based on two-component systems and internal sections, a polythermal solubility diagram for the systems H2C2O4·2H2O - CО(NH2)2 - H2Owas constructed in the temperature range from -11.2 to 92°C. The limits of crystallization of ice, dihydrate oxalic acid, carbamide and a new phase of carbamide oxalate were determined, and the composition was identified. The crystallization temperatures, viscosity, density and pH were established depending on the ratio of components when urea was added to oxalic acid. [ABSTRACT FROM AUTHOR]

Aliminium toxicity is major limiting factor of crop production in acidic soils. It is known that mechanisms of toxic effects of aluminium are differing in biochemical characters, research of aluminium toxicity complicated by variety of its chemical forms and migration in soil and water ability. The root exudates qualitative composition of common buckwheat was evaluated. Organic complexing agents – oxalic acid and phenolic compounds were revealed. The role of these complexing agents in the buckwheat aluminium resistance under acidic stress, participation in processes of external and internal detoxification was shown. Spectrophometric assay revealed an increase in root secretion of oxalic acid by 2.5 times and decrease in content of phenolic compounds in root exudates solution by 3 times upon aluminium (50 µM) treatment. In the meanwhile the same concentration of the metal had induced phenylalanine ammonia-lyase activity by 2 times.

The are results of tartaric, succinic, acetic, oxalic acids effects on growth processes in plants are shown. The potential to control the growth processes and physiological parameters in plants with different ecomorphotypes types of CO2 metabolism by application of the organic acids in 0.001–0.01 % concentration ware proved.

The nature of chemical dissolution of undoped and doped by the IV-A elements (Ge, Sn, Pb) of cadmium telluride in the (NH4)2Cr2O7-HCl-oxalic etching composition has been investigated. The projections of the equal etching rates of these semiconductors have been constructed, and the concentration regions of the polishing solutions have been determined. It has been shown that the dissolution of these materials is limited by the diffusion stages. Surface state after the etching has been investigated by the metallography and SEM. The composition of the near surface layers has been determined using energy dispersive X-ray spectroscopy. [ABSTRACT FROM AUTHOR]

This paper deals with the experimental research into the effectiveness of utilizing oxalic acid for decomposition of the phosphate component of phosphorites employing the trisubstituted calcium phosphate as a sample. Furthermore, the impact of such parameters as duration, temperature, the stoichiometric ratio of initial reagents is defined in the process of calcium phosphate dissolution. We determine that the calcium phosphate dissolution by the oxalate acid finishes in 30-45 minutes and the temperature at which the maximum expansion of calcium phosphate is 80 °C. The results obtained indicate the prospects of using organochemical leaching of phosphorites by the oxalic acid. [ABSTRACT FROM AUTHOR]