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

9-13

Authors: A.O. Kolbasiuk, A.S. Bushuev, G.A. Galstyan

The kinetics of the catalytic oxidation of ethylbenzene by ozone-air mixture in acetic acid is investigated. It is established that the selectivity of ethylbenzene oxidation by ethyl group increases significantly in the presence of manganese(II) acetate, whereas such an increase is low under the conditions of the catalysis by cobalt(II) acetate, and it almost does not change when using palladium, nickel and chromium acetates. The selectivity of the oxidation with side chain reaches 76% in the presence of manganese(II) acetate at a temperature of 283 K. Acetophenone (66%), 1-phenylethanol acetate (10%), and trace amounts of phenylglyoxylic and benzoic acids are found in reaction products; carbon(IV) oxide is detected in gaseous wastes. The main role of ozone catalysis consists in generating an oxidized form of manganese (i.e. Mn(IV)) which initiates the oxidation of ethylbenzene in side chain. We stated that 3.6 moles of ozone are consumed per 1 mole of ethylbenzene which has reacted; this is much higher than its theoretical needs for the formation of acetophenone and 1-phenylethanol acetate. The initial rate of ethylbenzene oxidation depends on the contents of substrate, catalyst and ozone; this is a first order reaction with respect to each of these reactants. A scheme of redox catalysis is considered; according to this scheme ethylbenzene oxidation occurs as an ion-radical non-chain reaction.

19-24

Authors: T.S. Chmilenko, A.Yu. Chernyavska, I.Yu. Chernoivanenko, F.A. Chmilenko

The effect of cationic polyelectrolytes – copolymers of acrylamide with a charge density of 5 to 95% and a molar mass of 4106 to 8106 g mol-1 on the chemical-analytical properties of brompyrogallol red and its complex with molybdenum is studied. It is shown that the dye deprotonation is accelerated and the pH range of the complex existence extends in the presence of the polyelectrolytes. The values of deprotonation constant for brompyrogallol red in the absence and presence of polyelectrolytes are determined. Inorganic salts destroy a dye-polymer associate, whereas a ternary dye-polymer-metal complex is stable under these conditions. The compositions of an associate brompirogallol red–polymer and polymer–metal–dye complex compound are identified. It is established that the charge density of the polymer affects the composition of the associate dye–polymer and does not influence on the composition of the polymer–metal–dye complex. The ternary metal-polymer complex brompyrogallol red–polymer–molybdenum has been used as an analytical system for the determination of polymer in tap water in the concentration range of 0.4 to 8 mg l-1.

32-36

Authors: V.L. Budzinska

The influence of a reactive oligourethane-semicarbazide on the process of the structure formation in organic-inorganic composites based on sodium silicate and polyisocyanate is studied in this work. It is established that the formation of a system with oligomer containing urethane results in obtaining a branched oligomer with flexible polyester block. The change in the structure of the reactive oligomer results in enhanced physical-mechanical properties of the composite synthesized. Using the modifier proposed provides a fourfold increase in the tensile stress and a twofold increase in the elongation at break as compared with the initial composites. It is shown that the introduction of the modifier into the system of segmented oligomer leads to the formation of more homogeneous and denser structure. The presence of the modifier leads to a decrease in the size of silicate particles formed in such systems in situ. As a result of developed interfacial area, the structure of the composites becomes more homogeneous providing improvements in mechanical properties. The presence of reactive modifier in the structure of organic-inorganic composites allows reducing the curing time of the system to minutes instead of several hours.

40-46

Authors: Yu.S. Dzyazko, L.M. Rozhdestvenskaya, Yu.G. Zmievskii, Yu.M. Volfkovich, V.E. Sosenkin, V.V. Zakharov, V.G. Myronchuk, V.N. Belyakov, A.V. Palchik

Organic-inorganic membranes were obtained by the modification of heterogeneous cation and anion exchange polymer substrates with zirconium hydrophosphate and hydrated zirconium dioxide, respectively, the modifier content was 3.5 to 4.3% wt. The inorganic modifiers were found to be mainly in a form of single nanoparticles and their aggregates (up to 500 nm). The effect of the modifiers on the porous structure of the membranes was investigated using the data of standard contact porosimetry. Aggregated nanoparticles are a barrier against additionally sorbed electrolyte improving migration flux of counter-ions through the membranes and minimizing concentration polarization when the current is lower than its limiting value. This allows us to avoid the precipitation of insoluble compounds directly inside membranes. The electrodialytic desalination of milky whey was investigated; both pristine and organic-inorganic membranes were applied. The composites provide preferable removal of hardness and phosphorus-containing ions from whey; moreover, a higher desalination degree is reached. The current efficiency for inorganic ions reaches 89% under the optimal operation conditions which involve particularly a contact of one side of the organic-inorganic membrane with acidic solution.

55-59

Authors: V.V. Kazakov

The influence of the condensed matters structure on some physicochemical properties and performance attributes of a ruthenium-palladium catalyst (named as RPC-1) is investigated; this catalyst being reactivated by the action of acoustic and electromagnetic fields and used in cleaning of carbon(IV) oxide from impurities in the production of urea. A mathematical model is proposed which takes into account the combined influence of acoustic and electromagnetic fields on the process of heat transfer in the system "solid–liquid". The influence of the composition of the condensed matters and acoustic and electromagnetic fields on some physical, chemical and technical characteristics of the waste ruthenium-palladium catalyst RPK-1 is studied. It is shown that the application of electromagnetic and acoustic fields is promising on various stages of catalyst preparation. It is concluded that the heat transfer by a joint action of electromagnetic and acoustic fields may be intensified in the solutions of mineral acids more strongly than in the solution of acetic acid or alkali.

66-73

Authors: O.O. Lipko, M.V. Burmistr, Yu.M. Kobelchuk, O.I. Mikhaylova, L.I. Sula

Polymeric composite material of construction purposes is developed which is based on a new water-soluble diphenylolpropane formaldehyde adhesive and discrete fiber filler with a chaotic design of reinforcing. This material is distinguished by enhanced complex of physical-mechanical and tribotechnical properties. A water-soluble diphenylolpropane formaldehyde resin is used as adhesive; it is received using a two-stage synthesis. In the first stage, the synthesis occurs under the conditions of novolak condensation of diphenylolpropane with formaldehyde in the presence of an acid catalyst and excess of phenolic component; in the second stage, the synthesis proceeds under the conditions of resole condensation in the presence of an alkaline catalyst and excess of formaldehyde. The resin is a light yellow liquid with the dry residual of 43 to 45% wt; the content of free phenol being less than 1% wt. The filler is basaltic fibers of Ukrainian production with different cutting length. The surface tension of adhesive and filler was determined. The matrix was explored by the method of infra-red spectroscopy. The rheological properties of press materials, the temperature dependence of their viscosity, the degrees of filling, and the cutting length of fibers were determined. The optimal technological parameters of the processing of press materials were ascertained. In order to evaluate the adhesive interaction of the developed water-soluble diphenylolpropane formaldehyde adhesive with basaltic filler, some pattern models were made; it was stated that the obtained polymeric matrix is characterized by a higher durability and enhanced adhesive interaction with basaltic fibers compared with a matrix on the basis of previously developed water-soluble diphenylolpropane formaldehyde resin. Some physical-mechanical and tribotechnical properties of the developed materials were determined. The material is characterized by high environmental safety; it is able to work in the high-loaded friction units in corrosive mediums instead of imported textolite.

80-86

Authors: Kostyantyn M. Sukhyy, Elena A. Belyanovskaya, Irina V. Sukha, Elena V. Kolomiyets, Alina V. Gavrilko, Mikhaylo P. Sukhyy

A composite sorbents "silica gel/sodium acetate" synthesized by sol–gel method is investigated in this work. The composite structure is investigated by wide-angle X-ray scattering. The change of the adsorption properties of CH3COONa crystals is revealed to be resulted from their dispersion up to nanoscale. The sorption capacity of the composite "silica gel–sodium acetate" is stated to be 0.42 g/g that exceeds noticeably the linear superposition of the sorption capacity of the silica gel and sodium acetate mechanical mixture. The difference between water sorption kinetics for massive sodium acetate and for "silica gel/sodium acetate" composite is shown. The solar adsorptive chiller design is developed. Its operating characteristics are determined when "silica gel/sodium acetate" composite is used.