Vol 89, No 1 (2016)

The review covers information from patents and papers that have been published in the past 5 years and deal with the synthesis of ester plasticizers for polyvinyl chloride. The main trends in the progress of this field are analyzed. Data on new esterification catalysts are presented. Particular attention is paid to plasticizers derived from terephthalic acid, which show promise for replacing toxic dioctyl phthalate. The results of studies on synthesis and properties of nonphthalate plasticizers based on benzene, toluene, naphthalene, cyclohexane, and norbornene are considered. Synthesis methods and prospects for using plasticizers derived from renewable vegetable raw materials, namely, citrates, succinates, triglycerides, fatty acid esters, and sugar derivatives, are discussed.

Process in which sulfur is produced from a gas containing 25–55% SO₂ was studied in order to evaluate the real efficiency of the catalytic post-reduction of sulfur dioxide in a pilot unit with gas flow rate of up to 1.2 nm³ h^–1 at the following temperatures (°C): thermal stage 850–1100, catalytic conversion 350–570, and Claus reactor 219–279. It was found that the conversion at 400–550°C and space velocity of 1600 h^–1 on AOK-78-57 promoted aluminum oxide catalyst provides full processing of organosulfur compounds (CS₂ and COS). The temperature dependence of the conversion/generation of hydrogen sulfide on AOK-78-57 catalyst corresponds to the equilibrium model. It was experimentally confirmed that the homogeneous reduction of sulfur dioxide gas with methane at T ≈ 1100°C, with catalytic post-reduction at 400–550°C and subsequent Claus-conversion of the reduced gas at 230–260°C, provide a sufficiently deep (by 92–95%) general processing of sulfur dioxide gas to sulfur.

Process in which double potassium-ammonium sulfate is produced from potassium chloride and sulfuric acid was studied. A thermal analysis of the compound KNH₄SO₄ was made and the melting and decomposition points of double potassium-ammonium sulfate were determined. An X-ray phase analysis revealed the processes occurring when double potassium-ammonium sulfate is calcined at temperatures of 330, 370, and 580°C. The chemical processes in which double potassium-ammonium sulfate decomposes to give ammonium hydrosulfate were examined.

Molecular layering method was used to synthesize on the surface of γ-Al₂O₃ vanadium-titanium oxide structures of varied composition and structure from the gas phase and niobium- and molybdenum-containing additives from the liquid phase. The resulting composites and the starting aluminum oxide were studied by X-ray diffraction analysis and chemical-analytical and adsorption methods. The catalytic properties of the synthesized products were examined in the oxidative dehydrogenation of ethane. It was shown that the activity of the samples is affected not only by the composition and structure of surface structures, but also by the relative amounts of components in mechanical mixing of vanadium-titanium oxide and niobium oxide supported systems.

Technological specific features of the solketal synthesis on a KU-2-8 cation-exchange resin were improved. Data are presented on the mutual solubility of the components in the glycerol–acetone–water and glycerol–acetone–water–ethanol systems. It is shown that use of ethanol for homogenization of the starting reagents is more than twice more efficient than performing the process with delivery of an emulsion of the reagents or reaching a full solubility of glycerol in acetone due to the 20-fold excess of the latter at 35°C. It is shown that the delivery of a glycerol emulsion in acetone to an immobile bed of a heterogeneous catalyst working in the falling-film mode leads to flooding of the reactor at spraying densities exceeding 0.15 m³ m^–2 h^–1.

The results of the electrochemical study of the Li–S_n system in the electrolytes consisted of LiN(CF₃SO₂)₂ and tetraethylene glycol dimethyl ether in relation to the LiN(CF₃SO₂)₂ concentration, temperature, and storage conditions are presented. The optimal concentrations of the salt component in salt-solvates were determined. These concentrations make it possible to obtain high stable values of the specific capacity in cycling and charge storage at room and elevated temperatures. It was shown that the operation stability of the electrochemical system Li–S_n–LiN(CF₃SO₂)₂ in salt-solvate solutions depends on solubility of the formed lithium disulfide, ratio composition of electrolyte and temperature.

The present work focuses on the synthesis of high surface area NiO nanoparticles through thermal decomposition of [Ni(binol)(bpy)]∙CH₃OH complex as a new precursor. [Ni(binol)(bpy)]∙CH₃OH (where binol = racemic-1,1′-bi-2-naphtholate and bpy = 2,2′-bipyridine) was synthesized from reaction of NiCl₂(bpy) with rac-Na₂(binol). The complex was characterized by elemental analysis and spectroscopy techniques of IR, UV-Vis, mass, ¹H and ¹³C NMR. The results revealed that [Ni(binol)(bpy)]∙CH₃OH was a paramagnetic tetrahedral complex. The physicochemical properties of the nanoparticles were characterized by various analysis techniques such as X-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and BET specific surface area. The used synthetic rout is facile and economic that makes it suitable for large scale production of pure nickel oxide nanoparticles.

The combustion and ultrasonic bath methods have been utilized to generate nickel spinel ferrite nanoparticles. Physical and chemical properties of generated nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and vibrating sample magnetometer (VSM). Between the nanoparticles generated by mentioned methods, there were differences in size, oxygen-metal bonding, and magnetic properties which have been investigated in the work.

ZnO was successfully prepared by the conventional synthetic route. Polyvinylpyrrolidone was used as soft-template to synthesize ZnO with controllable size and shape. It was found that ZnO was synthesized with average crystal size of 49 nm, as reported by an X-ray diffraction experiment. Scanning electron microscopy and transmission electron microscopy confirmed the hexagonal shape of the as-synthesized ZnO. The thus prepared ZnO colloidal particles exhibited numerous opportunities for numerous applications.

In the course of time, metallic structural systems working in corrosive salt media are in decay under their action. The service life of constructions can be made longer by protection with various primer anticorrosion formulations. For this purpose, a new protective material was developed, an epoxy primer based on ED-20 resin emulsified in water, modified with carbon nanoparticles.

Photopolymerizing formulations of urethane-acrylate and epoxy-acrylate oligomers with active diluents of varied functionality and molecular mass were studied. It was found that the functionality of the monomers strongly affects the mechanism by which protective properties of a coating are formed. The limits of the range of optimal concentrations of the active monomers were found. It was confirmed that the maximum protective properties of the coatings are observed when unifunctional and bifunctional active diluents are used in the mixture formulation in a stoichiometric or nearly so ratio. The possibility of creating formulations with nanosize particles of functional additives determining the purpose of a formulation (anticorrosive, decorative) was revealed and substantiated.

A film polymer nanocomposite with nanoparticles of a chalcogenide semiconductor, CdS, in a polystyrene matrix was prepared on the surface of 08kp steel. The barrier properties of the synthesized two-layer film nanomaterial in a 3 wt % aqueous NaCl solution were evaluated by measuring the electrode potential of coated and uncoated specimens and were compared with those of polymer films without nanofiller and with Fe₃O₄ nanoparticles. Introduction of hydrophobic CdS nanoparticles into the polymer matrix leads to significant enhancement (by ∼20%, as compared to Fe₃O₄) of the barrier properties of the polymer nanocomposite.

The effect of bicyclic bisureas (glycolurils) and their derivatives functionalized with hydroxymethyl, halomethyl, and dimethoxyphoshorylmethyl groups on the flame resistance and physico-chemical properties of synthetic isoprene and divinyl rubbers was studied, and the procedures for preparing these agents were suggested. The rubbers with the addition of the synthesized bicyclic bisureas demonstrated satisfactory levels of flame resistance and physico-mechanical parameters.

The possibility of using surface barrier discharge for the surface modification of polyester fabrics with the aim of making them more hydrophilic was studied. The action of surface-barrier discharge leads to the formation of hydrophilic oxygen-containing groups on the surface of polyester fabrics owing to weak degradation of poly(ethylene terephthalate) macromolecules, and the thread surface becomes rougher on the nanolevel. This leads to a considerable decrease in the contact angle and to an increase in the wettability of the polyester fabric, i.e., the fabric becomes considerably more hydrophilic. Modification of the polyether fabric with surface barrier discharge does not cause appreciable decrease in the strength and breaking elongation of the material.

A copolymer of N,N-diallyl-N,N-dimethylammonium chloride with maleic acid of constant composition was prepared under the conditions of radical initiation. The possibility of the functionalization of the copolymer with drugs containing amino groups by polymer-analogous transformations was examined. Conditions were found for preparing conjugates of the copolymer with isoniazid. The structures and the quantitative compositions of the conjugates were determined by ¹³С NMR spectroscopy, and the possibility of preparing conjugates with controlled drug content was demonstrated.