Removal of naphthalene and tar from coke–oven gas in primary cooling and condensation

This review covers research at AO Vostochnyi Nauchno–Issledovatel’skii Uglekhimicheskii Institut (VUKhIN) over the past 50 years on the extraction of tar and naphthalene in the primary cooling of coke–oven gas and also on related topics such as the conditioning of coal tar and the cooling of ammonia liquor in surface heat exchangers. Some laboratory results that were not published during the author’s lifetime are presented here for the first time.     

Formation of Hydroperoxy-, Keto- and Hydroxy-Dienes in FAME from Oils: Influence of Temperature and Addition of α-Tocopherol

The influence of temperature (40, 60 and 80 °C) and addition of α-tocopherol (0, 500 mg/kg) on the formation and distribution of the main oxidation products of linoleic acid, i.e. hydroperoxy-, keto- and hydroxy-dienes, were studied in samples of fatty acid methyl esters (FAME) derived from high-linoleic (HL) and high-oleic (HO) sunflower oils. In the range of temperatures studied, the formation of hydroperoxydienes showed monomolecular and bimolecular rate constants that ranged from 0.01 to 1 mmol^1/2kg^−1/2h⁻¹ and from 0.02 to 0.9 h⁻¹, respectively. The overall activation energies involved were similar for both samples and for the monomolecular and bimolecular periods (63–68 kJ/mol). The relative oxidation of methyl linoleate, which depended on the fatty acid composition of the FAME sample, was unaffected by temperature. At the three temperatures assayed, hydroperoxydienes constituted approximately 90 and 50% of total hydroperoxides in the HL and HO samples, respectively. Formation of keto- and hydroxy-dienes was influenced by temperature in a similar way to hydroperoxydienes and, consequently, changes in the distribution of compounds were not observed. The addition of α-tocopherol not only decreased the overall oxidation rate, but also affected the distribution of compounds. The content of hydroperoxydienes relative to that of total hydroperoxides was not affected by the presence of the antioxidant in the HL sample, whereas a significant increase (75%) was found in the HO sample compared with the control (50%). The addition of α-tocopherol in both samples also resulted in a slight increase of keto- and hydroxy-dienes in relation to hydroperoxydienes.     

Synthesis of porous carbon nanomaterials and their application in tetracycline removal from aqueous solutions

The low-cost and efficient elimination of tetracycline from wastewater and to decrease the concentration in soils, sediments, rivers, underground water, or lakes are crucial to human health. Herein, threedimensional porous carbon nanomaterials were synthesized using glucose and NH₄Cl by sugarblowing process at 900℃ and then oxidized under air atmosphere for surface functional group modification. The prepared 3D porous carbon nanomaterials were applied for the removal of tetracycline f...     

Migration Paths of Helium in α-Quartz and Vitreous Silica from Molecular Dynamics Data

The helium diffusion in -quartz and vitreous silica is studied by the molecular dynamics method. It is shown that, as the temperature increases, the motion of a helium atom in crystalline quartz changes over from vibratory motion about the equilibrium position at 300 K to free displacements throughout the bulk of the crystal at 750 K. The helium diffusion in -quartz and vitreous silica is described. It is demonstrated that even an insignificant number of structural defects increases the helium mobility.     

Synthesis and characterization of polymeric plasticizer from PET waste and its applications in nitrile rubber and nitrile–PVC blend

Polyethylene terephthalate (PET) waste is not biodegradable; thus, it will create environmental hazards if disposed in landfills. Therefore, the only way of addressing the problem of disposal of post-industrial and post-consumer PET wastes is through recycling. The polyester plasticizer for polyacrylonitrile butadiene rubber (NBR) and polyacrylonitrile butadiene–polyvinylchloride rubber blend (NBR–PVC) was obtained by the depolymerization of PET waste with 2-ethyl-1-hexanol. The PET waste was depolymerized until a polymeric plasticizer with the average molecular weight in the range of 450–900 g/mol was obtained. The polymeric plasticizer was characterized for acid and hydroxyl numbers, viscosity, density, FTIR, NMR and TGA/DTA thermogram. The prepared polymeric plasticizer was used in the preparation of nitrile rubber and nitrile–PVC rubber blend rubber sheets, where these sheets were tested for compatibility, tensile strength, elongation-at-break, hardness and ageing properties. Nitrile rubber and nitrile–PVC blend sheets were also prepared using DOP as a plasticizer and a comparative study with the synthesized polymeric plasticizer was made. It was observed that synthesized polymeric plasticizer provides excellent tensile properties and ageing resistance for high-performance applications as compared to that obtained from DOP. The end uses for nitrile rubber and nitrile–PVC rubber blend compounds are quite diverse, but they can be loosely categorized as being either general performances or higher performance applications. Each of these performance categories requires a different set of considerations in terms of compounding with plasticizers.     

Location of Mn in MnAPO‐11: influence of synthesis from aqueous and non‐aqueous media

MnAPO11 samples were synthesized from aqueous (MnAPO11(A)) and ethylene glycol (MnAPO11(NA)) media. The crystallinity of the samples was more when the synthesis was carried out in ethylene glycol. Chemical and thermogravimetric analyses reveal greater incorporation of Mn in the framework of MnAPO11(NA) than in MnAPO11(A). At least five different types of Mn(II) species are detected in the samples by ESR. The studies suggest that Mn is more homogeneously distributed in MnAPO11(NA) than in MnAPO11(A).     

Iodine content of cattle milk from mountain and coast from Perú

With the objective to establish the cause-effect relationship between a geological area and the iodine content in cattle milk, and to estimate the contribution of milk consumption to the dietary iodine intake, the iodine content in cattle milk from the sierra and the coastal regions of Perú was determined. Milk samples were collected of cows from the three main productive zones of Perú, 62 in Cajamarca, 42 in Arequipa, both in the sierra, and 27 in Lima at the coast. The measurement of iodine was made by the method of Zak, based on the Sandell- Kolthoff reaction. The median values obtained were 24 microg/L in Cajamarca, 34 microg/L in Arequipa, and 170 microg/L in Lima. The median value in the sierra, 26 microg/L, was significantly lower than the one found in the coast. Moreover, while in the former 81% of individual values were below 50 microg/L, in the latter, on the contrary, 77% were above 80 microg/L. These results confirm that the iodine content in cattle milk is related to ecological factors. At the same time, they demonstrate that the iodine content in milk from the sierra is six times lower than in milk from the coast, and also that its consumption does not contribute significantly to satisfy the human physiological requirements of iodine in that zone.     

Comparison of supercritical fluid and solvent extraction methods in extracting γ-oryzanol from rice bran

Organic solvents were compared with supercritical CO₂ relative to efficiency for extracting lipid and γ-oryzanol from rice bran. A solvent mixture with 50% hexane and 50% isopropanol (vol/vol) at a temperature of 60°C for 45–60 min produced the highest yield (1.68 mg/g of rice bran) of γ-oryzanol among organic solvents tested. The yield of γ-oryzanol without saponification was approximately two times higher (P<0.05) than that with saponification during solvent extraction. However, the yield (5.39 mg/g of rice bran) of γ-oryzanol in supercritical fluid extraction under a temperature of 50°C, pressure of 68,901 kPa (680 atm), and time of 25 min was approximately four times higher than the highest yield of solvent extraction. Also, a high concentration of γ-oryzanol in extract (50–80%) was obtained by collecting the extract after 15–20 min of extraction under optimized conditions.     

Evidence of hydrogen–boron interactions in diamond from deuterium diffusion and infrared spectroscopy experiments

We report on the first experimental evidence of hydrogen–boron interactions in boron-doped diamond. Deuterium diffusion studies in homoepitaxial B-doped diamond films reveal that hydrogen diffusion is limited by the B concentration and is characterized by a low effective diffusion activation energy. Infrared spectroscopy experiments show that boron acceptor electronic transitions disappear under hydrogenation. These results are consistent with hydrogen ionization and diffusion of fairly mobile H⁺ which form pairs with B⁻.     

Research on corrosion products and removal of salts in iron ware from Huaguang ReefⅠ

首次研究了“华光礁Ⅰ号”出水铁器腐蚀产物及有害盐脱除,其中HTQ6^#铁器锈蚀产物表面电阻率为（3×10³）～（1×10⁸）Ω,已完全矿化且具有磁性,腐蚀产物主要为Fe₃O₄、α-FeOOH、γ-FeOOH、FeOCl。为避免有害锈γ-FeOOH、相似文献   

Cloning of Δ12- and Δ6-desaturases from Mortierella alpina and recombinant production of γ-linolenic acid in Saccharomyces cerevisiae

Two cDNA clones with homology to known desaturase genes were isolated from the fungus Mortierella alpina. The open reading frame in one clone encoded 399 amino acids and exhibited Δ12-desaturase activity when expressed in Saccharomyces cerevisiae in the presence of endogenous fatty acid substrate oleic acid. The insert in another clone contained an open reading frame encoding 457 amino acids and exhibited Δ6-desaturase activity in S. cerevisiae in the presence of exogenous fatty acid substrate linoleic acid. Expression of the Δ12-desaturase gene under appropriate media and temperature conditions led to the production of linoleic acid at levels up to 25% of the total fatty acids in yeast. When linoleic acid was provided as an exogenous substrate to the yeast cultures expressing the Δ6-desaturase activity, the level of γ-linolenic acid reached 10% of the total yeast fatty acids. Co-expression of both the Δ6- and Δ12-desaturase cDNA resulted in the endogenous production of γ-linolenic acid. The yields of γ-linolenic acid reached as high as 8% of total fatty acids in yeast.     

Preparation of Cobalt Nitride from Co–Al Hydrotalcite and its Application in Hydrazine Decomposition

Alumina supported cobalt nitride [Co₄N–Al₂O₃ (HT)] with high cobalt loading has been prepared for the first time from Co–Al hydrotalcite precursors. The formation of the Co₄N phase was confirmed by XRD, H₂-TPR, and XPS. Compared with Co₄N/Al₂O₃ (IMP) prepared by conventional impregnation and nitriding, the hydrotalcite derived catalyst exhibited a much better activity for hydrazine decomposition as consequence of higher dispersion of active species.     

The dynamics of hydrogen bonds and proton transfer in zeolites – joint vistas from solid-state NMR and quantum chemistry

The different aspects of zeolite Brønsted acid sites are reviewed from the perspective of solid-state NMR spectroscopy and quantum-chemical calculations. The strength of the combined use of these two methods is demonstrated. Special emphasis is dedicated to the structure and dynamics of hydrogen-bonded complexes of zeolites with H₂O and CH₃OH.     

Electrolyte solutions in liquid ammonia—IX. Electrodeposition and electrodissolution of metals from their salts

Anodic dissolution and cathodic deposition of 20 transition metals in acidic solutions in liquid ammonia has been surveyed. The early transition metal elements Ti, Zr, V Nb, Mo and W form high oxidation-state insoluble amido complexes during anodic oxidation. Soluble ammines of normal metal oxidation states are produced with Cr(III), Mn(II), Fe(II), Co(III), Ni(II), Cu(II), Ag(I), Zn(II), Cd(II) and Hg(II) (Mn dissolves spontaneously). The metals Ru, Pd, Pt and Au only dissolve slightly after prolonged electrolysis. Anodic enrichment of Au in its alloys is unlike that in aqueous solution; in ammonia both Cu and Ag can be simultaneously depleted from a 9 carat gold alloy. Cathodic reduction of metal-bearing solutions follows wide variations of behaviour. Fe and Ru ammines reduce to amido-complexes with concomittant hydrogen evolution, but Cr is not reduced. Solutions of Mn, Co, Ni, Pd, Pt, Ag, Au, Zn, Cd and Hg give metallic cathode deposits under differing conditions. Electrodeposition is potential dependent for Ni, Cu and Ag; metal plate at low potentials, and powders at high potentials. The two different products are the result of reduction of species with different degrees of solvation.     

Role of fibre–fibre and fibre–matrix adhesion in stress transfer in composites made from resin-impregnated paper sheets

Paper-reinforced plastics are gaining increased interest as packaging materials, where mechanical properties are of great importance. Strength and stress transfer in paper sheets are controlled by fibre–fibre bonds. In paper-reinforced plastics, where the sheet is impregnated with a polymer resin, other stress-transfer mechanisms may be more important. The influence of fibre–fibre bonds on the strength of paper-reinforced plastics was therefore investigated. Paper sheets with different degrees of fibre–fibre bonding were manufactured and used as reinforcement in a polymeric matrix. Image analysis tools were used to verify that the difference in the degree of fibre–fibre bonding had been preserved in the composite materials. Strength and stiffness of the composites were experimentally determined and showed no correlation to the degree of fibre–fibre bonding, in contrast to the behaviour of unimpregnated paper sheets. The degree of fibre–fibre bonding is therefore believed to have little importance in this type of material, where stress is mainly transferred through the fibre–matrix interface.     

The roles of integrin β1 in phenotypic maintenance and dedifferentiation in chondroid cells differentiated from human adipose-derived stem cells

Objective

The aim of this study is to probe the intrinsic mechanism of chondroid cell dedifferentiation in order to provide a feasible solution for this in cell culture.

Methods

Morphological and biomechanical properties of cells undergoing chondrogenic differentiation from human adipose-derived stem cells (ADSCs) were measured at the nanometer scale using atomic force microscopy and laser confocal scanning microscopy. Gene expression was determined by real-time quantitative polymerase chain reaction.

Results

The expression of COL II, SOX9, and Aggrecan mRNA began to increase gradually at the beginning of differentiation and reach a peak similar to that of normal chondrocytes on the 12th day, then dropped to the level of the 6th day at 18th day. Cell topography and mechanics trended resembled those of the genes’ expression. Integrin β1 was expressed in ADSCs and rapidly upregulated during differentiation but downregulated after reaching maturity.

Conclusions

The amount and distribution of integrin β1 may play a critical role in mediating both chondroid cell maturity and dedifferentiation. Integrin β1 is a possible new marker and target for phenotypic maintenance in chondroid cells.     

Catalytic Activity of MCM-41–TBD in the Selective Preparation of Carbamates and Unsymmetrical Alkyl Carbonates from Diethyl Carbonate

The synthesis of carbamates 3 and unsymmetrical alkyl carbonates 5 by reaction of diethyl carbonate with aliphatic amines or alcohols has been realized by using as heterogeneous catalyst a hybrid organic–inorganic material prepared by anchoring TBD to MCM-41 silica. Products are obtained in high yield and very good selectivity and the solid catalyst can be recovered simply by filtration and reused for different cycles without apparent lowering of activity. A supported N-carbethoxyguanidinium active intermediate is proposed, and some spectroscopic data are shown to support the mechanistic hypothesis.     

Phase equilibria in water–salt systems from sodium,magnesium, and calcium nitrates and deicing properties of nitrate compositions

Phase equilibria have been studied in the sections of Mg(NO₃)₂–NaNO₃–H₂O and Ca(NO₃)₂–NaNO₃–H₂O systems at the ratio of salt components from 3: 1 to 1: 3 at temperatures of 0 to–35°C. A series of nitrate compositions has been determined, which are promising as deicing agents. Their theoretical (under equilibrium conditions) fusion ability with respect to ice at–5 to–10°C has been calculated. The corrosion activity of the composition of calcium and magnesium nitrates (1: 1) with respect to cement concrete (in collaboration with the test laboratory of OOO RSTs Opytnoe) has been measured. It has been found that the reagent meets criteria according to the action on cement concrete and can be used in aerodromes. This composition has been chosen as original for the development of a solid granular deicing agent on its basis for aerodromes.     

A kinetic study of Pd–Au catalyzed synthesis of vinyl acetate from oxidation of ethylene and acetic acid in heterogeneous gas reaction

While qualitative interpretation of the experimental results is often limited to the identification of global mechanistic phenomena, kinetic modeling is a more powerful tool for the identification of the chemical reaction network that can describe the experimental results. In this paper, kinetic study of vinyl acetate (VA) synthesis was performed in a fixed bed reactor with oxidation of ethylene and acetic acid in gaseous phase over Pd/Au/SiO₂ catalyst under the industrial relevant reaction condition as follows: temperature of 120–165 °C, at constant pressure of 8 bar and the ratio of catalyst mass to the feed (W/F) was maintained at 70 g/mol min. Variation in partial pressure and concentration of reactants have led us to determine the rate limiting step and therefore proposing a new rate low based on Langmuir-Hinshelwood–Hougen–Watson (LHHW) approached consistent with experimental observation while adapted through mathematical formulation with high reliance. So, the kinetic parameters were determined by the Levenberg–Marquardt algorithm. Effect of temperature has also been surveyed showing a decreased in selectivity due to the difference in reaction constants of main and side reaction rate and an increase rate due to the increase in apparent activation energy.