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Fine Chemical Technologies

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Vol 14, No 4 (2019)
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7-23 3528
Abstract

The review article focuses on the current state of synthetic and biological studies of ribavirin analogs. Ribavirin is a broad-spectrum nucleoside antiviral drug with a 50-year long history of research and application, but its mechanism of action still remains unclear. This article examines contemporary views on the antiviral and antitumor effects of ribavirin and its analogs and describes the contradictions and gaps that exist in our knowledge. In recent years, new nucleoside analogs of ribavirin have been synthesized. These ribavirin derivatives modified at the heterocyclic base, have the potential to become the antiviral and antitumor agents of the new generation. Thus, this paper presents a systematic review of antiviral activities, antitumor activities and structure–activity relationship (SAR) correlations of 39 ribavirin analogs created in the past 15 years. Biological targets and possible mechanisms of action of these new compounds are also discussed, as well as the prospects and possible directions for further research.

THEORETICAL BASES OF CHEMICAL TECHNOLOGY

24-32 404
Abstract

In this paper, extractive distillation flowsheets for water–formic acid–acetic acid mixtures were designed. Flowsheets not involving preliminary dehydration were considered, and the relative volatilities of the components in the presence of sulfolane were analyzed. The result of extractive distillation depends on the amount of sulfolane. The structure of the flowsheet is determined by the results of the basic ternary mixture extractive distillation. In three-column flowsheets (schemes I, II), water is isolated in the distillate of the extractive distillation column. In the second column, distillation of the formic acid–acetic acid–sulfolane mixture is carried out, yielding formic acid (90 wt %) and acetic acid (80 wt %). The recycled flow is returned to the first column. Dilution of the formic acid–acetic acid–sulfolane mixture with sulfolane (second column of flowsheet II) allows for acids of higher quality (main substance content equal to or more than 98.5 wt %) to be obtained. Flowsheet III includes four columns and two recycling stages. First, the water–formic acid mixture is isolated in the distillate of the extractive distillation column. Then, water and formic acid are separated in a two-column complex by extractive distillation, also with sulfolane. We were carrying out calculations for column working pressure 101.32 and 13.33 kPa. To prevent thermal decomposition of sulfolane, working pressure for regeneration columns was always 13.33 kPa. The extractive distillation column of the basic three-component mixture is the main factor contributing to the total energy consumption for separation (in all schemes).

CHEMISTRY AND TECHNOLOGY OF MEDICINAL COMPOUNDS AND BIOLOGICALLY ACTIVE SUBSTANCES

33-38 171
Abstract

Aqueous solutions of polyvinyl methyl ether were investigated in order to test whether it is possible to utilize them as bases for embolic agents used to deliberately block blood vessels. This may be necessary in the course of treatment of vascular abnormalities, tumors, as well as during the preparation of patients for surgery. The right branch of the binodal curve for the binary system “polyvinyl methyl ether–water” was drawn using the cloud point method and the lower critical mixing temperature (35.5 °C) was calculated. Furthermore, the exact concentration of polyvinyl methyl ether in aqueous solutions at which phase transition occurs (given the temperature of 35.5 °C) was found to be 30 wt %. The viscosity–velocity curves for the 30% solution of polyvinyl methyl ether, obtained by rheoviscometry in the temperature range of 5 to 36 °C, indicate that this aqueous solution has a low viscosity and behaves like a Newtonian fluid. However, at the temperature of 35 °C and higher, close to the phase transition, a significant deviation from its Newtonian behavior is observed due to precipitation of polyvinyl methyl ether as it forms a solid white mass. Through the use of the Arrhenius–Frenkel–Eyring equation, the activation energy of the viscous flow for polyvinyl methyl ether solutions was found to be 31 kJ/mol. Based on refractometry data, it was demonstrated that phase transition in aqueous solutions of polyvinyl methyl ether is reversible. This feature can facilitate medical equipment cleaning before introducing the embolic agent into a patient’s bloodstream. Finally, the investigation determined some parameters, in which the formation of embolic agents from a 30% polyvinyl methyl ether aqueous solution occurs (in situ in a blood vessel at a temperature of 35.5 °C).

SYNTHESIS AND PROCESSING OF POLYMERS AND POLYMERIC COMPOSITES

39-44 138
Abstract

In the course of this study, compositions and designed structures for the polysulfone (PSF) and short glass fibers systems were calculated. Additionally, disperse-filled polymer composite materials (DFPCM) based on PSF-190 were classified in accordance with their respective structures, and the optimal amount of glass fiber (13.5–18.5 vol %) was determined. This article describes the production of DFPCM using PSF and a short glass fiber with a twin-screw extruder (Labtech Engineering Company LTD, model Scientific FIC 20-40). Furthermore, optimal mixing parameters for the creation of composites wherein the glass fiber length exceeds the critical length (lcr) were established. The critical length was calculated, and the curves for fiber size distribution of polysulfone composites were depicted, and a difference in fiber concentration between the dispenser and the extrusion head (up to ~10–15%) was found when the fiber content was at 18–25 vol %. For the first time, optimal parameters (which pertain to medium-filled dispersions) for the structure of DFPCM based on PSF and short glass fiber are able to be demonstrated.

 

ANALYTICAL METHODS IN CHEMISTRY AND CHEMICAL TECHNOLOGY

45-58 243
Abstract

This work presents the results of a study of the resins of seven Ancient Egyptian mummies from the collection of the Pushkin State Museum of Fine Arts using a complex of analytical methods: gas chromatography, atomic emission and mass spectrometry. Natural bitumen and beeswax were identified in the resins using the gas chromatography–mass spectrometry method. Based on the results of hydrocarbon distribution in the profiles of n-alkanes in the resin coatings of the mummies and naturally occurring bitumen, it was assumed that the Dead Sea bitumen was used. The gas chromatography–mass spectrometry studies of mummy resins in the selected ion mode (m/z 217 and 191) provided additional evidence of the bitumen’s geographic origin. Atomic emission spectrometry with inductively coupled plasma was used as a means to determine the content of microelements. Vanadium, nickel and molybdenum were found in the tar of five mummies. The determined relative amounts of vanadium, nickel, and molybdenum in the resins of the studied mummies showed a good correlation with the available data on the content of these elements in the Dead Sea bitumen, as well as the Fayum mummy resin based on this bitumen. The advantages of using the method of identifying bitumen in mummy resins based on relative content of vanadium, nickel, and molybdenum were revealed.

MATHEMATICAL METHODS AND INFORMATION SYSTEMS IN CHEMICAL TECHNOLOGY

59-68 116
Abstract

The analysis of the urgency of developing a decision and support information-modeling system for safety in the chemical industry is carried out. The article also covers the main elements of this information-modeling system. Key normative documents backing up the knowledge base of such an information-modeling system are listed below. The algorithm of the safety decision supporting information-modeling system is proposed. A database model of the safety decision supporting information-modeling system is elaborated below. A production rule system is set forth to manage issuing recommendations on the robust decision support information-modeling system in the chemical industry based on a methodological document. An implementation plan is laid out for the robust decision support information-modeling system in chemical industry. It is a ready-made software package based on two-level (client–server) architecture of information systems. This article also contains recommendations based on a test case of a tank equipment total destruction. Results of the computational experiments’ simulation in the TOXI+Risk software corresponding to the test selected values are available.

69-76 118
Abstract

A generalized algorithm for the verification of functional models and the rules for the verification of diagrams related by levels of detail were developed in this paper. The algorithm is based on the analysis of a tree which describes the decompose relations in functional diagrams. At each step of the algorithm, a pair consisting of a parent diagram and a functional diagram is selected, and the correlation of the arrows and their roles is checked for both. The formalization of the verification rules was based on the set-theoretic representation of functional diagrams in the form of labeled oriented graphs. The rules make it possible to map the position and roles of the arrows associated with the detailed function block of the parent diagram to the arrows of the child diagram. The following rules for each of the possible arrow roles were established: “input”, “output”, “control”, “mechanism”. The use of the logic programming language PROLOG was proposed for the implementation of the algorithm. A knowledge base structure comprised of 3 interrelated predicates to describe the tree of diagrams, nodes and edges of the graphs was suggested. A query to check the verification rules was formed, and methods of binding variables and fixing roles were considered. The analysis and verification of a fragment of a functional model for the production of vinyl acetate from ethylene was conducted as an example. The functional diagrams for the processes “Condensate separation” and “Vinyl acetate isolation” connected by a decompose relation were developed, their set-theoretic models were constructed, and the use of rules for the verification of each type of arrow were considered.

77-86 137
Abstract

A series of operating (Laplace) non-standard images, the originals of which are absent in well-known reference books on operational calculus, are considered. By reducing one of the basic images to the Riemann-Mellin contour integral for the modified Bessel functions and analyzing the corresponding inversion formula using the approaches of the complex variable function theory, an analytical form of the original original is found, which is abrupt in nature with a break point. It is shown that analytical solutions of the corresponding mathematical models using the found originals have a wave character, which is expressed by the presence of the Heaviside step function in the solutions. The latter means that at any time there is a region of physical disturbance to the point of discontinuity and an unperturbed area after the point of discontinuity. The images studied are included in the operational solutions of mathematical models in many areas of applied mathematics. physics, thermomechanics, thermal physics, in particular in the theory of thermal shock of viscoelastic bodies, in the study of the thermal reaction of solids based on the classical Maxwell-Cattaneo-Lykov-Vernott phenomenology, taking into account the final rate of heat propagation. These models are needed to study the thermal reaction of relatively new consolidated structurally sensitive polymeric materials in structures exposed to high-intensity external influences. The analytical relations obtained for the originals and the original improper integrals resulting from them, containing combinations of Bessel functions, can be used in the general methodology of constructing and applying various mathematical models in a wide range of external influences on materials in many fields of science and technology.



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