Voprosy khimii i khimicheskoi tekhnologii (Issues of Chemistry and Chemical Technology)

12-22

Authors: L. Dubenska, S. Plotycya, M. Pylypets, S. Pysarevska

We have determined that diazonium salts of anaesthesin and novocaine are suitable derivatives for the polarographic determination of these anesthetics. The dependence of the current of the reduction peak of diazonium salts and azo compounds on the concentration of anesthetics is linear with good metrological characteristics. The individual polarographic determination of anaesthesin and novocaine in their mixture in the form of diazo- or azo compounds is not possible because of overlapping the reduction peaks related to individual anesthetics. However, it is possible to determine the total amount of the investigated local anesthetics by summing the heights of the peaks or peak areas of the anaesthesin and novocaine derivatives using the calibration plot as well as the method of additives. The developed methods of polarographic determination of anaesthesin and novocaine in the form of their derivatives were checked by analyzing model solutions and pharmaceuticals (a solution for the injections of novocaine, a combined antiseptic drug "Farysil"). The metrological characteristics of lidocaine determination in the form of 2,6-dimethylaniline diazonium salt are poor, and the method of derivatization is complicated and long-continued.

31-36

Authors: P.О. Nekrasov, О.М. Piven, О.P. Nekrasov, О.M. Gudz, N.О. Kryvonis

The enrichment of fats with omega-3 polyunsaturated acids increases the nutritive value of fats and makes them more health promoting by boosting the immune system and reducing blood coagulability, the level of neutral lipids and the risk of coronary heart disease and atherosclerosis. That is why it is important to develop scientific basis of the synthesis of these lipid systems. There have been created the mathematic model of kinetics of enzymatic glycerolysis of triacylglycerols enriched with omega-3 polyunsaturated fatty acids, enabling quantitative and qualitative assessment of the reaction composition. For the mathematic modelling of the process, a system of nonlinear differential equations has been created which describes the change in the content of the resulting substrates and reaction products through time. To determine acylglycerol composition of the reaction systems, the high temperature gas-liquid chromatography method was used. The simulation was performed using Mathcad 15 environment via the identification of the parameters of the model by means of a random multivariable search algorithm being called a method of complexes, in the course of which the errors between experimental and model data were minimized. The Runge–Kutta method with a variable step of the fourth order of accuracy was used as a numerical procedure for differential equations modelling. As a result of the calculations, the numerical values of the constants of direct and reverse reactions rates and the corresponding equilibrium constants were determined. Based on the received constants of homogeneous substrates mixtures the values of thermodynamic parameters and activation energies of the studied process have been calculated. The conclusions have been drawn about the contribution of each reaction, occurring during biocatalytic glycerolysis of triacylglycerols, to the process under consideration.

46-52

Authors: T. Panchenko, M. Evseeva, А. Ranskiy, Н. Didenko, V. Baumer

The template synthesis of complex compounds has some advantages over other methods, because it allows producing new macrocyclic coordination compounds with valuable practical properties. At the same time, the composition, structure and properties of the final complex compounds depend both on the nature of the metal cation and the presence of reactive centers of the organic ligand. The purpose of this work was to establish the main features of the formation of copper(II) and cadmium(II) complexes with salicylidenesemicarbazone and determine the composition and spatial structure of the synthesized coordination compounds. The paper reports the data on the synthesis of coordination compounds [Cd(Н2L)(H2O)Cl2] (І), [Cu(НL)Cl]2H2O (ІІ), Ba[Cu(L')]2 (ІІІ) and salicylaldazine (ІV) (where Н2L and Н3L' represent salicylic aldehyde semicarbozone and N,N'-bis(salicylidene)semicarbazide, respectively). The synthesis of the investigated coordination compounds was carried out by the interaction of hot ethanol solutions of salicylic aldehyde semicarbazone, МCl2хH2O (M2+=Cd, Cu; х=0; 2) and salicylic aldehyde in a molar ratio of 1:1:1 at the pH value of 9–10 which was adjusted by the addition of Ba(OH)2 dissolved in a water-ethanol mixture (1:1). The composition and structure of the synthesized complex compounds I–III were confirmed by elemental analysis and IR spectroscopy; X-ray diffraction analysis was also used in the case of compounds I, II and IV. The complexation of copper (II) and cadmium (II) salts with salicylidenesemicarbazone under the conditions of template synthesis was investigated. It was shown that the reaction proceeds rapidly with the formation of chloro (salicylidenesemicarbazone) copper(II) dihydrate in the case of copper(II) as a template center; the reaction yields cadmium (II) dichloroaquasalicylidenesemicarbazone complex in the case of cadmium (II). This is due to the template effect of the copper (II) cation, namely, a very significant change in the charge component at potential centers of complexation, which was confirmed by quantum chemical calculations. For salicylaldazine which was separated under the conditions of template synthesis of cadmium (II) complex, the mechanism of its formation with the use of initial salicylidenesemicarbazone and salicylic aldehyde was established.

62-68

Authors: V.S. Farafonov, A.V. Lebed, N.O. Mchedlov-Petrossyan

Properties of the standard solvatochromic Reichardt's dye 4-(2,4,6-triphenylpyridinium-1-yl)-2,6-diphenylphenolate in micelles of n-dodecyltrimethylammonium bromide were investigated by means of molecular dynamics simulations. The characteristics of the location and orientation of the dye molecule as well as the nature of its microenvironment were obtained. These characteristics were compared with those in micelles of cetyltrimethylammonium bromide (CTAB). Deeper immersion of the triphenylpyridium moiety in DTAB micelle was revealed, in accordance with the experimental data. Also, the characteristics of the dye in CTAB micelles of two sizes were compared. They were found slightly different: in bigger micelles, the dye is immersed deeper into the micelle, and is hydrated weaker. The ET(30) polarity parameter of the studied micellar solutions changes in the same order as the hydration of the oxygen atom of dye molecule in corresponding micelles.

76-86

Authors: R.D. Apostolova, Yu.V. Polishchuk

In this article, the results of the research on MnO2 polymorphs as suitable magnesium-inserting cathodic material for the secondary high energy magnesium batteries are critically reviewed. It is shown that MnO2 magnesiation differs from classic type of Li intercalation. Magnesiation of MnO2 can proceed by intercalation or conversion. Conversion with quick loss of the discharge capacity at cycling in "dry" non-aqueous electrolytes is observed in most of MnO2 polymorphs (α-, δ-, closed to γ- phases and OMS-5). Intercalation is more probable in spinel phase. The lack of the electrolyte suitable for effective MnO2 magnesiation is one of the major issues affecting successful realization of high energy Mg battery. Another challenge is slow Mg2+ diffusion in the cathodic host. Water addition to "dry" electrolyte improves MnO2 magnesiation. In this case, magnesiation proceeds through an intercalation-type reaction. However, the water is incompatible with Mg anode. New strategy for increase of the Mg2+ mobility is required. Dual Mg/Li electrolyte and some proposed solutions that could be successful strategies for further development of high energy magnesium batteries are presented.

92-96

Authors: V.I. Goleus, Yu.S. Hordieiev

The lead silicate system underlies many compositions of optical glasses with a high refractive index. Such expensive and rare earth oxides as GeO2, La2O3, Ga2O3, Bi2O3, etc. are also introduced into the composition of these glasses, besides the conventional oxides. The development of new compositions of optical glasses is most frequently carried out by a pilot and experimental method being a labor-intensive process and requiring the considerable material expenses for performing the experimental research. It is possible to appreciably decrease the scope of experiments using the calculation methods of preliminary estimation of the glasses properties. The purpose of this work was to develop the mathematical models of calculation for PbO–B2O3–SiO2–GeO2 based glasses, depending on their composition and optical constants (refractive index nD, mean dispersion (nF–nC) and dispersion coefficient D). In order to establish the interrelation between the optical constants and the composition of multicomponent oxide glasses, the development of mathematical models was carried out using an experimentally statistical method. The developed mathematical models are adequate to the experimental data and allow calculating the optical constants of glasses with the following mean-square deviations: nD=±0.014, (nF–nC)=±11.1•10-4, and D=±0.4. The specified accuracy is sufficient for solution of different practical tasks, which are connected with the selection of compositions of the optical glasses with a preset complex of the optical properties.

102-110

Authors: Ya.A. Kalymon, Z.O. Znak, A.B. Helesh, L.V. Savchuk

The paper presents the results of theoretical and experimental studies on the determination of kinetic characteristics of the absorption process of air oxygen by water in a bubbling mode. As a result of theoretical studies it is shown that the resistance of the mass transfer from the liquid phase exceeds the resistance of the gas phase (2.53...3.42)106 times in a bubbling mode. Therefore, the absorption factor (i.e. mass transfer coefficient) of the oxygen from the gas phase to the liquid phase is equal to the mass transfer coefficient from the liquid phase. With a decrease in the diameter of bubbles from 0.008 m to 0.002 m, the mass transfer rate increases 2.0 times. At low concentrations of oxygen in water (0.1 mol/m3), the rate of absorption increases with increasing the temperature and it decreases at higher concentrations (more than 0.1 mol/m3). It is experimentally determined that the dependences of some kinetic quantities (coefficients of mass output and mass transfer, absorption rates etc.) on the technological parameters correlate with those calculated by criterion equations, but their values are 16…30 times smaller. For slightly acidic waters (pH≤5.5), the rate of the absorption of air oxygen by water in a bubbling mode is higher than the rate of oxidation of Fe2+ ions; therefore, a simple apparatus with a continuous bubbling layer and an average diameter of bubbles of 0.003 m would be effective to remove iron from water. The degree and rate of absorption of oxygen increase in direct proportion to the increase in bubbling height. The findings are of practical importance because they can be used to develop economically feasible methods for the treatment of natural and waste waters, in particular for the removal of iron compounds.

116-124

Authors: A.V. Mishchenko, E.V. Mishchenko, E.A. Venger, D.S. Kachuk

The paper summarizes the results of the study devoted to the use of a new type of film formers, self-dispersing aqueous dispersions of polyurethane ionomers, as binders in pigment compositions for the textile materials printing. A distinctive feature of the polymers of this type is that their macromolecules contain various ionic groups introduced into the main chain of the urethane block-copolymer or the chain extender, in particular, the sulfo- or carboxyl groups. The colloid-chemical properties of aqueous dispersions of polyurethane ionomers of anionic and cationic types were investigated in terms of the physical and mechanical characteristics of polymer films and the quality indicators of printing by pigment compositions in which the dispersions under study were used as binders. It has been shown that polymers from the group of ion-containing polyurethanes having anionic character can be recommended as pigment binding agents. Polymers containing carboxyl groups are more effective as binders among the polyurethanes of the anionic type, because these polymers provide greater resistance to dyes by wet treatments, a milder stamp of printed textiles and stable printing results. A higher intensity of colors was observed which are formed with the use of carboxyl-containing polymers due to the lower polymer ability to microphase separation. This property is manifested in the heat treatment of printed textile material by the clouding of polymer films, which results in a decrease in the intensity of coloration. It has been shown that more intense and stronger colors are formed by using of cationic polymers as compared with the anionic ones (but the latter cannot be used due to their high coagulation ability as binding agents). Cationic polyurethanes can be recommended to be used with special equipment, for example, when printing on fabrics using airbrushes.

131-139

Authors: S.P. Rogalsky, V.V. Davydenko, O.V. Dzhuzha, O.P. Tarasyuk, L.G. Lyoshina, O.V. Bulko, V.I. Parkhomenko, O.A. Aksenovska

In this work, imidazolium ionic liquid was tested as a potential plasticizing and antimicrobial additive to polyvinyl chloride (PVC). The new hydrophobic liquid salt 1,3-dihexylimidazolium dioctyl sulfosuccinate (C6C6IM-DOSS) was synthesized. The composite PVC films containing 20, 30 and 40 wt.% of ionic liquid were prepared. According to thermal gravimetric analysis data, PVC/C6C6IM-DOSS composite is thermally stable to at least 190С that indicates its availability for the processing by conventional methods. It was found by differential scanning calorimetry that the ionic liquid has a noticeable plasticizing effect on PVC, decreasing its glass transition temperature from 83.5С to 44.8С at the content of 20 wt.%. An increase in content of ionic liquid to 30% did not cause further changes of glass transition temperature. Thus, the results of differential scanning calorimetry indicated the availability of the ionic liquid as a secondary plasticizer for PVC. It was revealed that C6C6IM-DOSS possesses excellent migration resistance that was about 1% after 42 days. The results of microbiological study showed high antibacterial activity of PVC films containing 3–4 wt.% of the ionic liquid against Gram-negative (Escherichia coli) and Gram-positive (Bacillus subtilis) bacteria.

149-153

Authors: V.G. Sozontov, B.M. Shukaylo, V.M. Moskalyk, V.V. Kazakov, O.V. Suvorin

This report summarizes the results of the study devoted to the main features and mechanism of the fabrication nitrogen oxides by various methods and their interaction with water solutions of urea (carbamide) and ammonium nitrate. The results of thermodynamic calculations revealed that the interaction of carbamide with ammonium nitrate proceeds with the heat release under certain conditions and the reaction equilibrium is shifted to the right side. The degree of transformation of initial reagents into the final products reached 100%. To create favorable conditions for the beginning of the interaction of urea with ammonium nitrate, the catalysts, nitrogen oxides, should be introduced into the mixture, these oxides being prepared by the reaction of copper with nitrate acid. The equilibrium constants of the decomposition reactions of ammonium nitrate were calculated, their values indicated shifting the equilibriums to the right side; the degree of decomposition of components reached 100% at the temperature of 2703500C. It was theoretically established that the interactions of nitrogen (I), (II) and (IV) oxides with urea occur with the release of a large amount of heat and their chemical equilibriums are completely displaced to the right side.

161-167

Authors: Khlibyshyn Yu.Ya., Pochapska I.Ya., Grynyshyn O.B., Gnativ Z.Ya.

This work reveled the effects of the ratio of acid tar coupled with straight-run petroleum tars, the temperature of the process, the specific delivery rate of acid tar to the reactor, the rate of temperature elevation in the reactor the final heating temperature of the bitumen mass in the reactor and the stirring intensity of the reaction mixture in the reactor on the quality and properties of the bitumen prepared from the acid tar. The experimental findings confirmed that sulfur compounds, particularly sulfonic acids, are reduced to elemental sulfur. However, an intermediate product (i.e. hydrogen sulfide) was found only in small quantity. It was determined that the maintenance of a certain delivery temperature of reagents and a speed of their movement allows avoiding vigorous vapor evolution and excessive growth of the reaction volume, especially due to foaming. It has been shown that the initial temperature in the reactor has a little effect on the main quality factors of bitumen (such as the softening point, ductility, penetration, solubility in benzene, and the content of water-soluble compounds, acids and alkalis in bitumen); however, it significantly influences the process flow.