卷 89, 编号 11 (2016)

New method for activating the quartz-leucoxene concentrate via dissolution of a part of silicon and aluminum compounds was suggested and verified in order to intensify the chlorination of the concentrate. The hollows and channels formed in the process in grains of the concentrate provide the transport of reagents and a large degree of recovery of titanium, vanadium, niobium, and tantalum.

The compositions, stability constants, and rate constants of intramolecular redox decomposition of cerium(IV) complexes with anions of aminoacetic (H₂NCH₂COOH), iminodiacetic [HN(CH₂COOH)₂], nitrilotriacetic [N(CH₂COOH)₃], ethylenediaminetetraacetic [(CH₂COOH)₂N(CH₂)₂N(CH₂COOH)₂], and hexamethylenediaminetetraacetic [(CH₂COOH)₂N(CH₂)₆N(CH2COOH)₂] acids were determined by potentiometric, spectrophotometric, and kinetic methods at pH in the range 1.3−2.0 in perchlorate and nitrate media at an ionic strength I = 0.1 and a temperature of 298.15 K. Direct linear correlation between the logarithms of the stability constants of the complexes, log β₁₀₁, and logarithms of the cumulative protonation constants, log В_m+k (k = 1–2), of aminopolyacetic acid anions L^m–, and inverse linear correlation between log β₁₀₁ and logarithms of the rate constants of intramolecular redox decomposition of the complexonates [CeL]^4–m (m = 1–4), log k_n=1, were found.

The formation of boehmite and hematite in dependence of the conditions of joint hydrothermal hydrolysis of carbamide and a mixture of aluminum and iron(III) chlorides in the presence of K, Na, Ca, and Mg chlorides at T = 160–200°C and P = 0.6–1.6 MPa was studied. It was shown that the amount of boehmite and hematite being formed in hydrolysis of Al and Fe chlorides strongly depends on pressure, temperature, hydrolysis duration, and composition of the model mixture of Al, Fe, Mg, Ca, K, and Na chlorides. It was found that a complete hydrolysis of AlCl₃ and FeCl₃ with 99% yield of boehmite and hematite occurs at the stoichiometric ratio between carbamide and aluminum and iron chlorides in the starting solution, whereas mostly iron oxyhydroxide [goethite FeO(OH)] and aluminum oxychloride [Al₁₇O₁₆(OH)₁₆Cl₃] are formed at nonstoichiometric ratios.

Experimental results on the influence exerted by pyridine additives on the selectivity of the process in which the styrene fraction is purified to remove the microscopic admixture of phenylacetylene at low (up to 30°C) temperatures by selective hydrogenation with catalysts on an aluminoborosilicate or silica matrix with filler-metals in the form of platinum or palladium are presented. It was shown that pyridine-modified catalysts in these systems are effective in the selective hydrogenation of phenylacetylene for purification of raw styrene. The modification of a platinum catalyst on the aluminoborosilicate support results in that a deep degree of purification (>95%) is achieved even at low (up to 50°C) temperatures. Use of catalysts composed of 0.160 wt % Pt and silica woven-glass fabric, modified with pyridine additives, leads to a substantially lower loss of styrene (from 0.48 to 0.31% in some cases) in the temperature range of 30–50°C. It was demonstrated that addition of substances containing a unshared electron pair can noticeably affect the selectivity of the process in which the styrene fraction is purified from its impurity content even in the order of 0.01%. Depending from the substrate composition and active filler-metal, the temperature, together with changing the support properties, exerts varied influence on modified metallic catalysts, which is manifested in change in the activation energy and, as a consequence, in that of the hydrogenation mechanism.

Study of the catalytic properties of the VMoTeNbO catalyst in the oxidative conversion of ethane to ethylene at pressures of 0.1 to 2.1 MPa demonstrated that the pressure positively affects the conversion of ethane and favors formation of oxygen -containing products of deep and partial oxidation: carbon oxides and acetic acid, respectively. With increasing pressure, the yield of the product of oxidative dehydrogenation of ethane, i.e., ethylene, decreases.

Pyrolytic tungsten coatings were deposited onto the surface of sol microspheres with tungsten hexacarbonyl used as precursor. A method was developed for reduction of germanium tetrachloride in the presence of a catalyst based on sol microspheres coated with pyrolytic tungsten. The method makes it possible to reduce the process temperature and diminish the number of stages in production of germanium. The kinetic characteristics of the catalytic reduction of germanium tetrachloride with hydrogen were determined.

The matrix conversion of natural gas into synthesis gas, in which the autothermal oxidation occurs in the surface combustion mode in a cavity of a closed three-dimensional matrix made of a gas-permeable material, was studied experimentally. The specific volumetric productivity of such converters considerably exceeds that of traditional types of converters and allows conversion of hydrocarbon gases of virtually any composition into synthesis gas. Prospects for practical use of the new type of converters are discussed.

Low-molecular-mass lignosulfonates (M_w = 9250 amu) are adsorbed more strongly onto ZnS from neutral solutions (pH 4.5–4.8), and high-molecular-mass lignosulfonates (M_w = 46300 rpm), from acid solutions (pH 1.4–1.5). The sorption of the low-molecular-mass sample at pH 1.5 is affected by competing sorption of the solvent (Н₂SO₄). The lignosulfonate samples studied are adsorbed onto zinc sulfide by the chemisorption mechanism.

Hot-cured epoxy compound based on ED-20 resin and isomethyltetrahydrophthalic anhydride was modified with alkanolamines of different structures. The influence exerted by the structure of alkanolamines on the structure and operation characteristics of modified epoxy–anhydride compounds was examined. Introduction of alkanolamines decreases the gel and cure times and enhances the operation properties of cured epoxy–anhydride compounds. The best products were obtained with alkanolamines derived from ethylenediamine. Their introduction into epoxy–anhydride compounds enhances by a factor of 1.5–2 the elasticity, tensile strength at uniform extension, and impact resilience of the cured formulations.

A series of transition metal-Mannich base complex was synthesized and screened for catalytic aquathermolysis of heavy oil and the results showed that the Ni(II)-Mannich base complex is the most effective one. The structure of catalyst was characterized by Fourier transform infrared (FTIR), ultraviolet and visible spectrophotometer (UV), and the group compositions C/H/N elemental analysis (EL), and thermogravimetric analysis (TGA) of the heavy oil were also conducted. The viscosity of the heavy oil can be decreased by 82.6% using 1.0 wt % catalyst with 15 wt % methanol in a reaction under 180°С for 24 h, and the composition analysis shows that 9.0% asphaltene is converted to resin and saturated HC. The group composition and the element content of the heavy oil before and after the aquathermolysis reaction were tested and analyzed.

Phenol is very useful intermediate in the manufacture of petrochemicals, drugs, agrochemicals, and plastics. Commercially, phenol is produced by a three-step, high-energy consumption process known as the cumene process. The conversion of a chemical to a value-added product is always economically desirable. More than 90% of phenol consumption in the world is manufactured by the multistep cumene process, in which acetone is coproduced in 1: 1 molar ratio with respect to phenol. However, the drawbacks of the three-step cumene process have spurred the development of more economical routes to decrease energy consumption, avoid the formation of explosive cumene hydroperoxide, and increase the yield. The objective of this article is to highlight benzene-to-phenol conversion technologies with emphasis on direct conversion methods. Gas phase and liquid phase reactions are the two main routes for direct oxidation of benzene to phenol. Indirect methods, such as the cumene process, and direct methods of benzene-to-phenol conversion are discussed in detail. Also discussed is the single-step reaction of benzene to phenol using oxidants such as O₂, N₂O, and H₂O₂. Catalytic conversion of benzene to value-added phenol using a chemically converted graphene-based catalyst, a cost-effective carbon material, is discussed.

The removal of dyes from waste water before their discharge into aquatic ecosystems is of substantial concern. Amongst functional macromolecules, the combination of polymers with dyes is a research field of enormous potential with regard to high-performance materials. The present study investigates interactions strategies between P(AM-co-AA) polymer with pyrazolone azo dyes in water as green solvent. These interactions were confirmed by FTIR spectroscopy, Ultra-visible spectroscopy, EDAX analysis, and FE-SEM analysis. Polymer P(AM-co-AA) has porous structure in which dyes present in the water get absorb hence it is use to remove pyrazolone dyes from water.