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Fine Chemical Technologies

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Vol 11, No 1 (2016)
View or download the full issue PDF (Russian)
https://doi.org/10.32362/2410-6593-2016-11-1

CHEMISTRY AND TECHNOLOGY OF INORGANIC MATERIALS

5-22 175
Abstract
The present review is devoted to consideration and generalization of a number of synthetic methods for lanthanide oxoiodides preparation as well as to consideration of their structural particularities and thermal stability. Phase diagrams with the participation of REE oxoiodides, alkaline metal iodides or silver iodide are given and discussed. All the systems are characterized by the solid solution formation on the basis of the pure compounds, while the systems with the participation of alkaline metal iodides are characterized by the formation of incongruent melting compounds. Structural data concerning oxoiodides of lanthanides with different oxidation states and with the participation of some other elements (carbon, nitrogen, barium, osmium, etc) are present and overviewed. Possible areas of application (catalysis, X-ray detectors, medical diagnostics) including distinct luminescent properties of Ce-, Pr-, Nd-, Sm-doped REE oxoiodides are underlined.
23-28 148
Abstract
Cerium(III) nitrate and urea solution mixture were treated by hydrothermal and microwavehydrothermal methods, as a result cerium(III) carbonate hydroxide nanoparticles (22-37 nm) were obtained. Cerium(III) carbonate hydroxide nanoparticles, encrusted by palladium were obtained using palladium reduction process from cerium(III) carbonate hydroxide solution. It is shown, that palladium occurrence disturbs hard hydrogen bond system, leading to carbonate hydroxide nanoparticles structure disorder and also increases efficiency of catalytic reactivity process.
29-33 167
Abstract
The cation exchange properties of mordenite (a Nakhchivan natural zeolite) were studied. Ion exchange of the original cations - sodium, potassium and calcium - by magnesium, strontium, cadmium, zinc and nickel cations was carried out. It was found that in the case of Zn cations cation exchange occurs readily at a high speed and the maximum value of the degree of exchange. A low value of the degree of cation exchange is observed for Mg. This is due to the large hydration shell of magnesium, which adversely affects the cation exchange. High values of the exchange rate of Na+ cations have already been explained at the first exchange of low content of sodium cations and their location mostly in exchange for positions available. The lesser ability to exchange K+, Na+ cations than contained in the natural zeolite is due to several reasons. With an increasing number of degrees of ionic exchange value exchangeable cations K+ vary to a greater degree than the degree of exchange of the cations Na+. Firstly, the content and size of the K+ cation are greater than those of the Na+ cations. Furthermore, a part of the K+ cations is in exchange for hard cancrinites cells. It has been found that the degree of cation exchange of K+ (αK), contained in the original zeolite, with Mg2+, Ni2+, Sr2+, Zn2+, Cd2+ cations is considerably lower than the values of the degree of cation exchange of Na+ (αNa) at the same cations.
34-39 127
Abstract
Analytic solution of nonlinear Leybenson equation in the theory of filtration is obtained. Analytical solutions of the partial differential equations are presented in the explicit algebraic form. The integral surfaces in three dimensions are presented.
40-44 104
Abstract
The comparison of energy consumption for rectification of binary mixtures in one-column and twocolumn apparatuses was carried out with the use of vapor flow energy from the first column for heating the second column. It is shown that the expected two-fold reduction of the flow of heat energy is impossible due to the decrease of the internal energy-saving.

CHEMISTRY AND TECHNOLOGY OF MEDICINAL COMPOUNDS AND BIOLOGICALLY ACTIVE SUBSTANCES

45-52 181
Abstract
The determination of the title compound in the model microencapsulated insecticidal tools is considered, as well as the ability to conduct analysis in mixtures with other encapsulated means on the basis of a pyrethroid (cypermethrin, deltamethrin, tetramethrin, permethrin, phenothrin, transfluthrin) and phosphorus-containing derived insecticidal substances (chlorpyrifos). The conditions of direct analytical determination and the stage of sample preparation with the previously described methods are adapted. The content of lambda-cyhalothrin together with cypermethrin in microencapsulated compositions is determined by spectrophotometric method taking into account the absorption of trace contaminants - technical substances and building blocks of microcapsules (phospholipids). RP HPLC method shows the possibility of separate determination of lambda-cyhalothrin and several pyrethroids (except for cypermethrin), and chlorpyrifos, in the hypothetical compositions in a joint encapsulating order to obtain a highly active insecticide that enable overcoming the resistance of insects to a number of inactive substances.

SYNTHESIS AND PROCESSING OF POLYMERS AND POLYMERIC COMPOSITES

53-58 125
Abstract
Experimental studies of sodium methacrylate and methacrylamide copolymerization in aqueous solutions with a total monomer content of 34-50% were accomplished. Potassium persulfate was used as the initiator. Three variants of the process operation conditions were investigated: isothermal, quasi-isothermal and adiabatic. The effect of temperature, initial concentration of monomers and initiator on the rate of copolymerization, the extent of monomers conversion, the duration of the process, the reaction mass viscosity were studied under isothermal conditions. The copolymerization takes place at a constant rate at all temperatures in the range of 55-80°C until conversion is less than 70%. This behavior is typical for the polymerization system with initial total concentration of monomers of about 4.4 mol·L-1 and above. It is found that the reaction rate is directly proportional to the initial concentration of the reaction system. Increasing temperature reduces the viscosity of a 1% aqueous solution of the product, thus reducing the average molecular weight of the copolymer. By means of studying the copolymerization under adiabatic conditions the dependences of the monomers conversion degree, the viscosity of a 1% aqueous solution of the product and the reaction mass temperature upon copolymerization time were obtained. In the adiabatic mode the monomers conversion is less than 70%, the viscosity of a 1% solution of the reaction mass is approximately 13·10-6 m2/s, and the temperature rises to ~ 120°C. The product is a polymer gel, water-swellable and soluble in an aqueous alkaline medium. The quasi-isothermal mode of copolymerization with the same duration allows obtaining the degree of conversion of about 94% and a viscosity of the reaction mass of about 400·10-6 m2/s. An important advantage of the copolymer obtained in the quasi-isothermal mode as compared to that obtained in the adiabatic conditions is complete water solubility. Based on experimental results, the recommended conditions for the sodium methacrylate and methacrylamide copolymerization are as follows: the monomers concentration in the reaction mass is 5.55-6.75 mol·L-1; initiator concentration is 2·10-3 - 6·10-3 mol·L-1; copolymerization temperature is 55-65°C.
59-66 104
Abstract
The article describes the results of a research on polycondensation “in situ” in the process of partial hydrolysis of dimethyldimetoxysilane and dimethyldiacetoxysilane as compared with similar data for the dimethyldichlorosilane and homofunctional condensation of dimethylsilandiol. The effect of the molar ratio of components on the composition of products of partial hydrolysis of the functional dimethylsilanes and dependence of the monomer conversion degree (Xm) vs. conversion of functional groups (Xf) are presented. It is shown that as the conversion of functional groups in composition products increases the share of dimethylcyclosiloxanes and reaches more than 99% (when Xf →1). It is found that among the monomers (CH3)2Si(OCH3)2 < (CH3)2Si(OCOCH3)2 ≈ (CH3)2SiCl2 the proportion of unit-to-unit assembling of oligomeric molecules, which are created by heterofunctional condensation of hydrolysis products and the proportion of organocyclosiloxanes are increasing. It is assumed that the heterophase process which is responsible for the lack of hydrolyzing agent due to its slow diffusion is the cause of the unit-to-unit assembling.

MATHEMATICAL METHODS AND INFORMATION SYSTEMS IN CHEMICAL TECHNOLOGY

67-74 130
Abstract
This paper considers the problem of thermal shock in the case of a massive body in different conditions of heating and cooling. The most dangerous mode of heating was identified. The influence of inertial effects on the value of emerging thermal stress was investigated. A new equation of compatibility of stress with the inertial effects, which generalizes the known Beltrami-Mitchell relation for quasi-static cases, was obtained by methods of the tensor algebra. The theory of thermal shock in solids was developed in terms of dynamic problems of thermoelasticity in different forms of heat stress: temperature heating; thermal heating; heating medium. Equations for the calculation the jumps in the front of thermoelastic waves were obtained. The most dangerous mode of thermal shock was identified. The effect of relaxation in thermal problems was described in the context of the investigation of thermal stress state of a massive body. It was shown that an increase in relaxation time, i.e. heating rates of the boundary surface of the body, causes a reduction of thermal stress maxima. Original results of the thermal reaction of a solid to cooling were obtained. It was shown that, in comparison with the heating mode, the cooling mode is more devastating, especially for nearsurface layers of solids. The role of the relaxation temperature in the cooling mode was identified. New functional structures were proposed as analytical solutions to the major dynamic problems of thermomechanics on the basis of the use of the Kar functions, which are relatively new.
75-78 117
Abstract
A substitution of an non-homogeneous term and of a differential operator by the difference of Laplace operators in the direct co-ordinate system and in the turned one in the partial differential equations of first, second and third order is proposed. The numerical solution obtained by solving the substituting equation corresponds to the exact solution of the initial equations.


ISSN 2410-6593 (Print)
ISSN 2686-7575 (Online)