Fine Chemical Technologies

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Vol 12, No 4 (2017)
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5-35 334
Basic knowledge of mankind so far relates to the description of electrons and atoms in the material in a state of equilibrium, where the behavior changes slowly over time. The electron diffraction with a high temporal and space resolution has opened the possibility of direct observation of the processes occurring in the transient state of the substance (molecular movie). Here it is necessary to provide a temporary resolution of the order of 100 fs, which corresponds to the transition of the system through the energy barrier of the potential surface, which describes the chemical reaction - the process of the breaking and the formation of new bonds between the interacting agents. Thus, the possibility of the investigation of the coherent nuclear dynamics of molecular systems and the condensed matter can be opened. In the past two decades, it has been possible to observe the nuclear motion in the temporal interval corresponding to the period of the nuclear oscillation. The observed coherent changes in the nuclear system at such temporal intervals determine the fundamental shift from the standard kinetics of chemical reactions to the dynamics of the phase trajectory of a single molecule, the molecular quantum state tomography.
36-42 306
Experimental results confirming the mechanism of pyrocarbon formation through the steps of high-molecular pyrolysis products forming in the gas phase are presented. Adsorption of high-molecular pyrolysis products on the active centers of the substrate localized at the boundaries of the contacts of its crystallites and their subsequent carbonization is confirmed. The decreasing in the length of the substrate crystallites contact boundaries leads to the increase in the content of high-molecular compounds in the gas and to the decrease in the hydrogen concentration is shown. The relation between the composition of the exhaust gas and the surface of the sealing material creates the prerequisites for controlling the pyro-consolidation process according the composition of the off-gas. The composition of high-molecular liquid pyrolysis products was identified. The difference in the composition of high-molecular pyrolysis products of the propane-butane fraction and the electric cracking gas was established. The influence of raw materials and pyrolysis conditions on the group composition of high-molecular pyrolysis products formed is shown.


43-49 349
It is theoretically justified that for the scheme of separation of three-component mixtures with the release of the high-boiling component in the first column there is a region of initial compositions for which the heat costs are the least. An expression describing the boundary of the optimality regions of different separation schemes is given. The calculation of the heat costs for both rectification schemes of the three-component mixtures performed using the Aspen Plus software package confirmed the theoretical justification for the existence of optimality regions for each of them. With the help of the concept of internal energy saving, the advantage of one or another scheme of separation of a three-component mixture is explained.


50-57 342
Chlorides of polyorganosiloxanes with 1-methyldiazolylmethylene groups were synthesized using the reaction of quaternization of poly(chloromethyl)organosiloxanes with 1-methylimidazole. The degree of completeness of this reaction was determined, and the products were characterized by the data of elemental analysis, NMR spectroscopy (1H and 29Si), TGA and DTA. The possibility in principle of obtaining statistical polyorganosiloxanes with the [1-(methyl)imidazolyl]methyl substituent in the frame of the siloxane macromolecule by quaternization of the corresponding chloromethyl-substituted organosilicon polymers with 1-methylimidazole is shown. By the method of TGA and DTA, it was found that the destruction of the obtained ionic liquids occurs when heating them in air above 265 °C. The possibility of fixing the formation of an imidazolium salt by the appearance of a chemical shift in the region ~10 ppm in the 1Н-NMR spectrum has been established.


58-64 299
A preparative method for the synthesis of 8-oxo-2'-deoxyguanosine (8-oxo-dG) giving a high yield up to 80% and suitable for laboratory use is suggested. The urgency of the development of this method is associated with the need to obtain large quantities of 8-oxo-dG for the study of biological and pharmaceutical activity. Evidence of this need was obtained in the last decades, when the mechanisms of the interface of DNA repair with intracellular signaling through 8-oxo-dG were discovered and its anti-inflammatory and protective effects were revealed. The suggested method is based on the scheme used to prepare 8-oxo-dG-containing oligonucleotides, but has a number of important modifications. The use of N,N-dimethylformamide as a solvent makes it possible to increase the yield of the nucleophilic substitution reaction and avoid expensive and complicated further purification of silver acetate. Control of the reaction kinetics allows achieving the maximum yield and purity of the product. Alkaline hydrolysis, in contrast to ammonolysis, provides complete and rapid removal of acyl groups, and reversed-phase chromatography on silanized silica gel is an effective and inexpensive method of purification. Such a purification scheme minimizes contamination of the product with residual organic solvents, which is important for biological experiments. From the economic point of view, it is advantageous because of the absence of expensive solvents and the possibility of reusing the carrier. The method makes it possible to obtain pure 8-oxo-dG in preparative amounts and exceeds both its prototype and other existing techniques in the final output. Some intermediate compounds and significant methodological features of the reaction are described.
65-74 276
The use of TRIS derivatives as the kernels of branching fragments is a modern method of preparing carbohydrate-containing dendrimer-like amphiphiles. A scheme of the synthesis of derivatives of trivalent neoglycolipids with terminal residues of D-mannose and a branching component based on 2-amino-2-hydroxymethylpropene-1,3-diol (TRIS) differing in the degree of saturation of the hydrocarbon chains is developed. The preparation of the hydrophilic part of the target molecules was carried out with the use of the reaction of 1,3-dipolar cycloaddition followed by conjugation with the hydrophobic component according to the carbodiimide method with the addition of HOBt as a catalyst. Approaches to the formation of target designs - liposomes based on phosphatidylcholine and synthesized neoglycolipids - and their physical and chemical properties, such as the size of particles and stability are investigated. The activity of the obtained compounds in the composition of liposomes loaded with the antibiotic meropenem with respect to Escherichia coli strain is carried out. An opportunity of changing the profile of the action of a liposome sample containing neoglycolipids by choosing various methods of its preparation that is promising for further research in this direction is revealed.


75-84 305
This paper presents the results of studies of seed copolymerization of glycidyl methacrylate with ethylene glycol poly(glycidyl methacrylate) on seed particles in order to obtain partially crosslinked polymer microspheres with a diameter of about 3.5 microns for use in immunochemical reactions, as carriers of bioligands. The physico-chemical properties of polymeric microspheres obtained under different conditions were studied by the following methods: the diameters of the particles - by electron scanning and light microscopy; the wetting angle - bу the method of "lying droplets"; the sedimentation velocity - by the macromethod in a capillary tube by the movement of the (polymer slurry)/water phase boundary (buffer solution); the zeta-potential - by dynamic light scattering. Having studied the physical-chemical properties of all polymer slurries we concluded that the optimal particles to create on the basis of their diagnostic test systems with high sensitivity working on the principle of latex agglutination reaction are poly(glycidyl methacrylate) particles with equal percentage of glycidyl methacrylate and ethylene glycol dimethacrylate aminated with hexamethylendiamine in the environment of n-propanol, because they have a sufficient number of amino groups and do not lose their sedimentation properties after all stages of the synthesis.
85-90 354
The properties of butadiene-nitrile rubbers obtained by various methods of synthesis and isolation from latex and rubbers based on them were studied in the article. The surface free energy of samples was determined using the Owens, Wendt, Rabel and Kaelble method. It was shown that the surface energy of elastomeric materials is affected 1) by non-rubber components, the content and nature of which are determined by the method of obtaining and isolating rubber from latex and 2) by the number of nitrile groups in the rubber macromolecule. The kinetics of vulcanization of rubber compounds based on the investigated rubbers has been studied. It was shown that rubber compounds based on rubbers containing a residual emulsifier are vulcanized longer. Elastic-strength properties were studied, and it was concluded that rubbers based on butadienenitrile rubbers synthesized by various methods with the same content of bound nitrilacrylic acid have different physico-mechanical properties and cannot be used interchangeably without changing the formulation and technological parameters of their processing.


91-97 260
The matter of thermal conductivity is considered in an approximation, in which the free length of phonons is limited and doesn't depend on temperature, so that the temperature behavior of thermal conductivity coefficient is only determined by thermal capacity. In these conditions the problem of non-stationary thermal conductivity of chain structures at low temperatures (T<<θ, θ for Debye temperature) is solved with the use of the variables separation method. Solutions relating to the areas with both moving and fixed borders are considered. Special choice of border motion law allowed us to bring the initial problem to the problem with fixed borders, but with reformed equation of thermal conductivity. The results obtained can be applied for studying the thermal conductivity of crystal carbon existing in the form of carbine (synthetic polymeric chained structure). The found solutions of the equation of non-stationary thermal conductivity of highly anisotropic crystals can also be used while studying thermal conductivity in melted quartz fibres and highly oriented fibres of polyethylene. Melted quartz fibres have a disordered atomic structure, but with an uninterrupted net of silica-oxygen links. The effective sizes of crystallites in such substance are of the same order as those of separate tetrahedrons of silica dioxide. One may assume that in this case the free length of phonons remains constant, limited only by the size of the crystallites, and the decrease of thermal conductivity coefficient while lowering the temperature is caused only by the decrease of heat capacity. Polyethylene of a higher crystallinity degree has almost the ideal structure of lamellar type. The borders of lamellas scatter phonons, so that the probability of scattering practically doesn't depend on the length of phonon's wave. Thus, in this case the free length of phonons won't remain constant and is determined by the size of lamellas, so that thermal conductivity will be proportional to heat apacity.apacity.
98-105 202
Due to the relevance of the problem of implementation of the Best Available Techniques (BAT) in the chemical industry of the Russian Federation it is necessary to develop a scientifically defensible transition process to BAT for chemical manufactures. For this purpose, the functional modeling methodology was used in the graphical notation IDEF0 standardized in the Russian Federation. The production process for the transition of a chemical manufacture to BAT was described as a hierarchical structure represented as a diagram consisting of functional blocks and arcs that connect them. First, the simulation object was represented as a single block with boundary arrows, which show how the simulated process is related to the environment. Then it was sequentially decomposed into diagrams of a lower level, i.e., stepwise hierarchical decomposition of the top-level context diagram was performed, which resulted in a set of interrelated diagrams that describe the processes and relationships between them and the environment. This allows us to clearly establish the order of actions that are performed at each stage of the transfer of chemical manufacture to BAT.

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