Химия

Method of low-temperature differential thermal analysis using a differential scanning calorimeter of heat flow was first studied system n-nonadecane – cyclododecane. The studied systems are of the eutectic type. Alloy of eutectic composition contains 37,0 wt % of cyclododecane and melts at a temperature of 20.4 °C.

Potentiometric cefepime sensors based on an organic ion-exchanger such as cefepime with tetraphenylborate are developed. The optimum membrane composition is established. The surface and volume properties of membranes are investigated. The constant of dissociation of the ion-exchanger in a membrane phase is calculated by stationary resistance. Potentiometric determination of cefepime in water and biological environments is present.

The process of cold phosphating (25°C) of the carbon steel St3 in the zinc nitrate-phosphate system was studied using a set of physical, chemical and electrochemical methods. The electrochemical nature of steel phosphating in the given conditions was confirmed. Ways of improving the phosphating process to obtain corrosion-resistant phosphate coatings on steel were identified: modifying the phosphating solution with an inorganic silicon-containing additive and the subsequent processing of phosphate films in an aqueous solution containing silicon compounds.

The aim of this study was consumption is preliminary deoxygenation source of sulfur dioxide from methane-free oxygen and sulfur vapor to the catalystic’s reactor. It has been found that, the use of deoxygenated methane as agent leads to a significant increase in process speed and vaporized sulfur to improve the sulfur yield by increasing the concentration of sulfur dioxide entering in the catalyst of gaz mixture.

The method of derivative spectrophotometry with measurements at zero-crossing wavelenghts is proposed for simultaneous quantitative determination of synthetic food dyes Tartrazine (E102) and «Sunset yellow» (E110). The method was tested on model mixtures and applied to determine the content of dyes in carbonated soft drinks. The error does not exceed 7%.

Manifestation system to effect luminescence complexes of samarium (III) and gadolinium (III) in the presence of thenoyltrifluoroacetone and 1,10-phenanthroline. Increased intensity supersensitivity transition in luminescent ion complexing agent depends on the nature of the ligand and the formation of micro- and nanoparticles in the system. It is found that in the presence of tetracycline derivatives sensitized fluorescence intensity decreases.

The adsorption properties of granular glauconite sorbents and their modified analogues against with respect to Fe2+, Mn2+, Cu2+, Cd2+ cations were studied and compared with natural untreated samples. The process was carried out in a static mode. The maximum adsorption of samples and the calculated adsorption equilibrium constants were determined. It was established that modified sorbents possessed the most activity adsorption against cations in pelleted samples. Modification was carried during sequential heat and acid-salt treatment.

Phase equilibria and critical phenomena in component mixtures of the cut 1 of the quaternary system Potassium Nitrate – Water – Pyridine – Butyric Аcid whose constituent ternary liquid system had a closed binodal curve were studied by means of the visualpolythermal method within 5–60oC. The volumes of two monotectic states in the composition tetrahedron have been found to be in contact via critical tie lines with increasing temperature.

Presented first the results of the research of phase equilibria of threecomponent system azelaic acid – glutaric acid – sebacic acid by used the microcalorimeter heat flow. Identified eutectic composition containing azelaic acid – 33,0 wt %, glutaric acid – 54,0 wt %, sebacic acid – 13,0 wt %. The melting temperature of the alloy eutectic composition in the three-component system is 70,5 °C, the specific enthalpy of melting is 82 ± 10 J./g.

In recent years, much attention is paid to the environmental safety of industrial materials and products widely used in the construction of residential and public buildings. Housing quality is influenced by the choice of «clean» construction materials not containing any chemical substances harmful to human health, namely: mercury, lead, cadmium, chromium, their salts and isotopes, as well as some naturally occurring radionuclides (radium 226, thorium 232, potassium 40, and cesium 137).