Fine Chemical Technologies

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Vol 10, No 3 (2015)
View or download the full issue PDF (Russian)
5-49 265
Spectra of internal friction for plasticized and non-plasticized poly(methyl methacrylate) (PMMA) are obtained by dynamic methods of external distortion effect within a frequencies range from 10-2 to 103 Hz and within a temperature range from -50 up to +250°С. Areas of local non-elasticity are revealed, and mechanisms of dissipative losses occurring in various temperature areas of the spectra are determined. Calculation of physico-chemical characteristics is made for each of the revealed relaxation processes, and the dependence of these characteristics on molecular mass and various doses of gamma and neutron irradiation is determined. Special temperature points are revealed in the area of structural vitrification, and possible causes of their emergence are discussed considering model representations of the fluctuation theory of density. Methods of analysis and assessment of the microinhomogeneity degree of PMMA structure are considered using the fractional-exponential Kohlrausch function in the Boltzmann-Volterra integral equation as relaxation memory function. Theoretical analysis of “Deborah number” concept application for the description of inelasticity processes of relaxation origin is made using the phenomenological generalized Maxwell model.
50-55 246
The object of the research is a butanol-toluene mixture (BLS), which is a waste product of organosilicon enamels and consists of organic substances. In order to create a basic technological scheme of separation, thermodynamic-topological analysis was applied that takes into account the peculiarities of the rectification process in the poly-azeotrope mixture. The presence of 7 binary and 5 ternary azeotropes in the system was found. Singular points of the pentatope are considered. The distillation and rectification zones are determined. Flow graphs options separation were drawn, which can be the basis for the development of a technological scheme for the separation of the studied mixtures.


56-61 322
Variants of tinosan and triclosan extraction from jellous disinfectants followed by UVdetermination is considered. The best extractant is hexane in a neutral (weakly acidic) solution or under acidification in case of studying alkaline disinfectants. The correct determination of the title compounds is possible in the analysis of their 2-propanol solutions by reversed-phase HPLC, both individually and as mixtures with other phenolic disinfectants. Spectrophotometric determination may be made only for the individual title compounds (extraction with hexane).
62-69 228
The work presents the results of a research on the effect of water extracts of herbal preparations on phosphate concrements of different phase composition taken in vitro from 56 patients. Interrelation between the composition of the extracts and the pH of urine was found. Recommendations on the selection of herbal preparations providing favorable conditions for the litholysis of phosphate concrements were given.


70-76 207
An information-calculating system (ICS) that allows computer simulation of processes of semiconductor technology associated with the formation of single crystals and epitaxial heterostructures based on semiconductor AIIIBV compounds was developed. The ICS database covers 9 of AIIIBV compounds and solid solutions based on semiconductor AIIIBV compounds in 18 ternary and 15 four-component systems. The ICS allows solving problems related to the calculation of heterogeneous equilibria in these systems, stability of the formed solid solutions to decay, kinetics of epitaxial growth of heterostructures and non-equilibrium phenomena accompanying heteroepitaxy. In order to create the ICS, we used object-oriented programming Object Windows application programs compiled in the programming language Borland C++ in the Windows environment. Examples of the use of the database for particular semiconductor systems are presented.The above list of problems could be solved with the use of the ICS. The ICS can be used both in research and in educational practice.
77-84 248
During the study of cyclohexene oxidation by p-benzoquinones into cyclohexanone in water-organic solutions of cationic complexes of palladium(II) it was demonstrated that the initial reaction rate R0 depends complicatedly on water molar fraction for three studied solvents: acetonitrile (AN), dimethylformamide, and dimethylsulfoxide. In order to explain the obtained bimodal dependence for the example of AN-water system, modeling of phase equilibrium in the studied system was performed. The existence of two- and three-phase immiscibility areas as well as a three-component heteroazeotrope was found. By UV spectroscopy it was stated that varying of water molar fraction in the binary solvent substantially changes the state of starting cationic complexes [Pd(АН)x(H2O)4-x]2+. For mathematical description of medium effect on R0 value three models were proposed taking into account different factors, such as: a) physico-chemical properties of binary solvent; b) composition of possible associates AN-water; c) composition of starting [Pd(АН)x(H2O)4-x]2+ complexes. The adequate description of bimodal dependency was obtained in the model considering the changes of [Pd(АН)x(H2O)4-x]2+ complexes composition with simultaneous presence of an associate of (АН)2(H2O) composition.
85-90 224
The thick-film phosphor coating on glass substrates based on nanostructured cerium doped yttrium-aluminum garnet powder and low melting glass was prepared. A new method of obtaining nanostructured powders of yttrium-aluminum garnet doped by cerium ions, based on the combustion method of nitrate salts in the presence of organic fuel is developed. The modes of synthesis, structural and spectral-luminescent characteristics of the nanostructured powders are optimized leading to garnet of chemical composition Y3-хCeхAl5O12 (х = 0.02–0.06) with the particles size of 40–60 nm, spherical form, a specific surface of 50 m2/g. The luminоus composition was prepared by mixing of components with isopropanol, further the slurry was casted on a glass substrate and dried up. The glass substrate with a covering was located in the muffle furnace, gradually heats up to temperature of 650°C and is maintained within 30-60 minutes, then slowly cooled with the furnace. Dependences of spectral-luminescent characteristics of coatings with respect to concentration of phosphor powders, nature and concentration of diffusing components of silica glass powders are revealed. At excitation on λ=440-460 nm phosphor coatings based on cerium doped yttrium-aluminum garnet with silica glass powder as filling agent demonstrate the highest luminescence intensity in the range of 500–700 nm. Model samples of discrete ceramic remote converters in the form of a thick-film covering deposed on smooth and grooved glass substrates, with concentration of the phosphor powders up to 30 mas.% are fabricated. Nanostructured phosphor coatings based on YAG:Ce powders and low-melting glass were used in construction of remote converters of light-emitting-diode lighting devices. The models of white light LED lamps were made using nanostructured phosphor coatings.

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