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

3-11

Authors: A.P. Avdeenko, S.A. Konovalova, I.Yu. Yakymenko, V.M. Baumer, S.V. Shishkina, V.V. Pirozhenko

Hydrazones of 1,4-benzoquinone, which have a wide range of biological activities, can be synthesized in the reactions of 4-{[(arylsulfonyl)oxy]imino}cyclohexa-2,5-diene-1-ones or N-(4-oxocyclohexa-2,5-diene-1-ylidene)arylsulfonamides with N-substituted hydrazines. In this study, the reaction of 2,6-disubstituted 4-{[(tolyl(methane)sulfonyl)oxy]imino}cyclohexa-2,5-diene-1-ones with aroylhydrazides gave N'-(3,5-dialkyl-4-oxocyclohexa-2,5-diene-1-ylidene)aroylhydrazides, which can be obtained by cross-synthesis in the reaction of N-(3,5-dialkyl-4-oxocyclohexa-2,5-dien-1-ylidene)arylsulfonamides with aroylhydrazides. As a result of the reaction of 4-{[(tolyl(methane)sulfonyl)oxy]imino}cyclohexa-2,5-dien-1-ones with phenylhydrazine, stable 4-hydroxyanilinium tolyl(methane)sulfates were isolated. Their structures were confirmed by X-ray diffraction data. We suggested that at the first stage of the reaction between 4-{[(tolyl(methane)sulfonyl)oxy]imino}cyclohexa-2,5-diene-1-ones and hydrazines, the N–O bond of starting 4-(oxyimino)cyclohexa-2,5-diene-1-one was broken forming sulfonic acid and corresponding quinoneimine. The latter either can be reduced to corresponding aminophenol under reaction conditions or can react with an excess of N-substituted hydrazine yielding corresponding hydrazide. The formation of N'-(4-oxocyclohexa-2,5-diene-1-ylidene)arohydrazides is facilitated by a lower basicity of hydrazide and a lower redox potential of quinoneimine.

16-23

Authors: V.V. Halysh, M.I. Skiba

We investigated chemical composition and sorption properties of lignocellulosic complexes of wastes of agroindustrial complex, namely crushed shells of apricot, cherry and peach seeds, and walnut shells. Chemical analysis revealed that walnut shells show the highest content of polysaccharide components. Cherry and peach seed shells are characterized by a higher content of aromatic components (lignin). Based on the results of sorption of benzene vapor, the following sequence of the volumes of adsorption pores was found: walnut shells (0.03 cm3 g–1)=apricot seed shells (0.03 cm3 g–1)>peach seed shells (0.02 cm3 g–1)>cherry seed shells (0.01 cm3 g–1). The sorption capacity of biosorbents towards methylene blue was investigated as a function of pH of an aqueous solution, process duration, and initial dye concentration. It was established that the maximum efficiency of sorption is achieved at pH 6, while the minimum value corresponds to low pH values. Probably, an increase in pH value leads to deprotonation of carboxyl groups of biosorbents followed by changes in their surface charge into negative. This causes a decrease in electrostatic repulsion forces between the positively charged dye cation and the surface of the biosorbents. Therefore, the sorption centers are formed. The data on kinetics of sorption showed that during the first 30 min of contact the absorption of 55–60% of the dye cations occurs on the biosorbents, whereas complete sorption equilibrium is achieved within 120–180 min. The following sequence of the sorption capacity of lignocellulosic materials towards methylene blue was established: apricot seed shells (43.9 mg g–1)>walnut shells (37.8 mg g–1)>peach seed shells (30.1 mg g–1)>cherry seed shells (26.5 mg g–1). The Freundlich isotherm is the most suitable for describing the cationic dye absorption by biosorbents, and the calculated values are in good agreement with the experimental data.

35-44

Authors: O. Kostiv, O. Korkuna, M. Sheredko

We developed two fast, simple and sensitive spectrophotometric methods for the determination of ceftazidime in drugs by using phenolic reagents resorcinol and 2-methylphenol. The methods are based on a previous antibiotic diazotization in the medium of hydrochloric acid (CHCl=12 M) and its following azo coupling with reagents in an alkaline medium with the formation of effective analytical forms that allow determining ceftazidime and have maximum absorbance at 519 nm and 516 nm for resorcinol and 2- methylphenol, respectively. The azo coupling products of diazotized ceftazidime exhibit effective molar absorptivity in the range of (6.31–6.84)103 M–1 cm–1. Stoichiometric ratios of the azo compounds components were established using continuous variations methods and they were the same in both cases (1:1). The developed methods allow determining from 2.75 to 185.5 g mL–1 of ceftazidime with resorcinol (LOQ=2.54 g mL–1) and 0.32191.3 g mL–1 of ceftazidime with 2-methylphenol (LOQ=0.28 g mL–1). The developed methods have been successfully tested in the analyses of one-component preparations (powders for injection solutions).

55-61

Authors: L.K. Patrylak, A.V. Yakovenko

Alkylation of isobutane with butenes is one of few important petrochemical processes that is still implemented using liquid acids. New highly active solid alkylation catalysts are investigated for century. The development of new rapid methods for testing catalysts will contribute to progress in this area. Therefore, the aim of the work was to test the possibility of conducting a bimolecular reaction of alkylation of isobutane with butenes in a microreactor in a pulsed mode of feeding. A zeolite-containing alkylation catalyst was synthesized and characterized by X-ray diffraction analysis, temperature-programmed desorption of ammonia and low-temperature nitrogen adsorption. Catalytic studies were performed in a microreactor built into the gas chromatograph scheme, which provided online analysis of the reaction products. The isobutane /butenes mixture was fed into the helium carrier gas stream via a loop. Testing was performed at 80, 100, 135 and 1850C. It was found that a significant amount of products is not desorbed by the carrier gas and is retained by the catalyst at reaction temperatures, while an increase in desorption temperature to 3800C promotes removing the products from the catalyst surface. The highest yield of products was 27% at 800C. With increasing the reaction temperature, the yield drops to 15%. It was shown that the developed method of testing of alkylation catalysts is promising for further use in the search for efficient solid-phase alkylation catalysts.

71-78

Authors: N.M. Rezanova, Yu.O. Budash, V.P. Plavan, V.I. Bessarabov

The influence of nanoparticles made of ifferent metals oxides (ZnO, Al2O3, TiO2, and ZnO/Al2O3) on the in situ formation of microfibrils by the components of a dispersed phase was studied in a thermodynamically incompatible blend of polypropylene/copolyamide (PP/CPA). The viscosity of the melts was determined by capillary viscometry method. Elastic properties were evaluated by the degree of extrudate swelling. The morphology of the compositions was studied by optical polarization microscopy. The method of image analysis was used to quantify the structural characteristics of the blends. It was established that the introduction of 1.0 wt.% of nanoparticles of the studied oxides made from different metals allows tuning the microstructure of the melt of the PP/CPA blend, which is realized in the course of extrusion. More perfect morphology is formed in nanofilled systems: the average diameter of PP microfibrils decreases and their mass fraction increases. The modifying effect of oxide nanoparticles is manifested due to their influence on interfacial phenomena and rheological properties of nanofilled PP melt. The viscosity of the PP melts increases and their elasticity decreases in the presence of nanoparticles of the studied metal oxides. The values of the ratio of the viscoelastic characteristics of the dispersed phase and the matrix in nanofilled systems depend on the nature of oxide and indirectly correlate with the microstructure of the extrudate. As these ratios approach unity, the diameter of PP microfibrils decreases and their share increases. The efficiency of the studied oxides to improve the microfibrillar structure increases in the following series: ZnO, Al2O3, TiO2, ZnO/Al2O3. The obtained results demonstrate the possibility to create the microfiber textile and filter materials with improved consumer characteristics by adjusting the phase morphology of the blends.

90-100

Authors: L.L. Rudneva, S.I. Bukhkalo, O.V. Lakiza, O.V. Chervakov

We investigated the possibility of a complex use of vegetable waxes as modifiers of surface properties of polymeric composites. The wax samples were extracted from vegetable raw materials and then introduced into the rubber formulations used for the manufacture of the sidewalls of passenger tires and pigmented paints as a dispersant additive. Physical-mechanical properties of the obtained compositions were determined. The introduction of the investigated wax into serial rubber formulations does not impair the technical characteristics of the mixtures. The investigated waxes ensure a good protection of the elastomeric compositions against atmospheric aging. The waxy substances can be effectively used as additives that increase the ability of inorganic pigments to dispersion. The results showed that the introduction of the wax increased the hardness of the film coatings of paint-and-lacquer materials, the gloss of the prepared coatings being not substantially decreased.