Химия

Application of multivariate regression methods for catalimetry simultaneous determination of iridium (IV) and rhodium (III) based on oxidation of N-methyldiphenylamine-4-sulphonic acid by periodations in weak acid medium was investigated. The data structure of the kinetic measurement was studied with Principal Component Analysis, it was found that the distribution of the samples corresponds to an increase in the total concentration of the catalysts of the PC1 and change the concentration ratio Ir: Rh on PC2.

Structural and energetic parameters of neodymium, europium, terbium and erbium complexes with 2- and 3-methoxybenzoic and 3,4-dimethoxybenzoic acids were studied. Correlation between Ln-O bond energy and temperatures of decomposition of studied compounds was found.

Phase equilibria and critical phenomena in the water-i-butyric acid binary system were studied by the visual polythermal method over the temperature range –10–30°C. The system is characterized by delamination with an upper critical solution temperature (UCST) equal 25.8°C. In the system at –1.8°C, these occurs a nonvariant monotectic equilibrium whose solid phase are ice crystals. The phase diagram of the system is plotted.

Techniques of determination of the main substances in capsules of cephalexin and tablets of cefuroxime axetil have been elaborated. For separation of ancillary compounds, the two modes have been approbated, i.e. filtration and centrifugation. The advantage of the second means has been shown.

The method of capillary electrophoresis to determine the content of caffeine and food additives: ascorbic (E300), sorbic (E200), benzoic (E210) acids; sweeteners – saccharin sodium (E954), acesulfame potassium (E 950) in wines, energy drinks and tea. The comparative characteristic of the caffeine content, and the aforementioned food additives in beverages. A comparison with the corresponding regulations. It is shown that the concentration of benzoic acid in beverages above the maximum allowable concentration in beverages Flesh and MONETO.

The reaction of 1,3-dipolar cycloaddition of conjugated aryl(hetaryl) methylideneacetones, which containing various peripheral substituents, with azomethine ylides was carried out. It was established that the interaction is not chemoselective and proceeds with the participation of two non-equivalent reaction centers of dipolarophile with high diastereoselectivity. The products of cycloaddition were a mixture of structural isomers endo-cycloaddition. Monoenone transform to spyropyrrolidines with high endo-stereoselectivity.

The conditions for the preparative synthesis of spiro-fused hydropyrimidinthiones based on carbonyl substrates and thiobarbituric acid were found. Schemes of condensation carbo- and heterocyclization are presented. Regio- and stereoselectiveness processes was established.

A technology for magnetite nanoparticles surface modification by polyethylenimine was proposed. The sizes of the nanoparticles using transmittance microscopy method were determined. The influence of pH, time of mixing, sorbent and antibiotic concentration on the enrofloxacin sorption was investigated and optimal conditions of extraction were found.

The work is devoted synthesis, investigation and application of composites based on calcium carbonate microspheres, with embedded nanoparticles of magnetite (Fe3O4), coated by silver nanostructured shell. This composite (SERS-substrate) was used for surface-enhanced Raman spectra (SERS) registration of rhodamine 6G and different pharmaceuticals such as ipratropium bromide, chloramphenicol, propranolol, pindolol, tamoxifen, diltiazem.

The state of monoaminooksidasy arginine and ?-amino acids in aqueous media. Built chart the distribution of ionized forms of arginine and valine at varying pH. Pakistan the possibility of Express electoral pH titrations of arginine in mixed solutions monoaminooksidasy ?-amino acids. The interval defined concentrations of 46,3–217,8 mg . Error does not exceed 5.5%.