Influence of preliminary treatment on activity and selectivity of Co-alumosilicate catalyst in hydrocarbon synthesis from CO and H2

The temperature and medium of preliminary treatment of 10% Co/SiO ₂·Al₂O₃ influence the activity and selectivity in hydrocarbon synthesis from CO and H₂. Treatment with NH₃ reduces the yield. Increasing the treatment temperature leads to a loss of activity and a change in the composition of hydrocarbons formed. The reason for deactivation is a change in the catalyst surface texture, its adsorptive properties, and the ability to be reduced.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1709–1713, August, 1990.     

High-pressure synthesis of carbamates by the carbonylation of aromatic nitro compounds in cyclohexanol

A study was carried out on the high-pressure carbonylation of nitrobenzene and 3-chloronitrobenzene by CO in cyclohexanol in the presence of PdCl₂-FeCl₃-pyridine with the formation of cyclohexyl-N-phenylcarbamate and cyclohexyl-N-3-chlorophenylcarbamate in 90–95% yield and nitro compound conversion of 95–99%. The feasibility of the repeated use of this catalyst was demonstrated.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1885–1887, August, 1991.     

Characteristics of the catalytic action of Co systems in the synthesis of hydrocarbons from Co and H2

Conclusions On the basis of experimental data, assumptions have been made concerning the possibility of prediction of the properties of Co catalysts for the synthesis of hydrocarbons from carbon monoxide and hydrogen with due regard for the properties of the supports, the nature of the thermodesorption of CO from the surface of the catalyst, and the method of its preparation.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 60–66, January, 1984.     

Computer-aided determination of relative stereochemistry and 3D models of complex organic molecules from 2D NMR spectra

A method for elucidation of the relative stereoconfiguration of natural product molecular structures and their 3D models based on NOE data and the application of a genetic algorithm is described. The method is applicable mainly for rigid polycyclic structures commonly encountered in natural products. It is demonstrated that the technique of simulated annealing cannot be easily used when dealing with low-weight fused ring molecules but the application of a genetic algorithm is proven successful. Examples of a typical genetic algorithm workflow and the optimization of the algorithmic parameters are discussed. The efficiency of the approach developed here is demonstrated on the complex natural products of both Taxol^® (C₄₇H₅₁NO₁₄) and brevetoxin B (C₅₀H₇₀O₁₄).     

The problem of joint optimization of product parameters and statistical quality control plans using a quantitative index

We solve the problem of joint optimization of quality assurane and choice of a quality control plan using a quantitative index for the case of normally distributed quality parameters. Some estimates of the efficiency of the proposed approach compared with the classical method are given.Translated from Statisticheskie Metody pp. 80–97, 1982.     

One‐Step Synthesis of Self‐Supported Nickel Phosphide Nanosheet Array Cathodes for Efficient Electrocatalytic Hydrogen Generation

Nickel phosphide is an emerging low‐cost, earth‐abundant catalyst that can efficiently reduce water to generate hydrogen. However, the synthesis of nickel phosphide catalysts usually involves multiple steps and is laborious. Herein, a convenient and straightforward approach to the synthesis of a three‐dimensional (3D) self‐supported biphasic Ni₅P₄‐Ni₂P nanosheet (NS) array cathode is presented, which is obtained by direct phosphorization of commercially available nickel foam using phosphorus vapor. The synthesized 3D Ni₅P₄‐Ni₂P‐NS array cathode exhibits outstanding electrocatalytic activity and long‐term durability toward the hydrogen evolution reaction (HER) in acidic medium. The fabrication procedure reported here is scalable, showing substantial promise for use in water electrolysis. More importantly, the approach can be readily extended to synthesize other self‐supported transition metal phosphide HER cathodes.     

Conversion of synthesis gas into alcohols on supported cobalt-molybdenum sulfide catalysts promoted with potassium

The use of transition metal sulfides as catalysts for the synthesis of alcohols can solve the problem of catalyst resistance to sulfur. Catalysts based on molybdenum sulfide of different compositions (promoted with Co and K) were synthesized with the use of various supports (aluminum oxide, aluminum oxide modified with silicon oxide, Sibunit, and titanium silicate) and tested in the reactions of alcohol synthesis and the hydrofining of a mixture of thiophene with n-1-hexene. The dependence of catalyst activity in the synthesis of alcohols on support pore size was demonstrated. It was found that an increase in the potassium content of the active phase of a catalyst increased its activity in the synthesis of alcohols and decreased it in hydrodesulfurization and hydrogenation reactions. Transmission electron microscopy data made it possible to quantitatively evaluate the effect of a potassium additive on the morphology of the active phase; the hypothesis that potassium was intercalated between the layers of molybdenum sulfide was proposed.     

New TEMPO–Appended 2,2′-Bipyridine-Based Eu(III), Tb(III), Gd(III) and Sm(III) Complexes: Synthesis,Photophysical Studies and Testing Photoluminescence-Based Bioimaging Abilities

Linked to Alzheimer’s disease (AD), amyloids and tau-protein are known to contain a large number of cysteine (Cys) residues. In addition, certain levels of some common biogenic thiols (cysteine (Cys), homocysteine (Hcy), glutathione (GSH), etc.) in biological fluids are closely related to AD as well as other diseases. Therefore, probes with a selective interaction with the above-mentioned thiols can be used for the monitoring and visualizing changes of (bio)thiols in the biological fluids as well as in the brain of animal models of Alzheimer’s disease. In this study, new Eu(III), Tb(III), Gd(III) and Sm(III) complexes of 2,2′-bipyridine ligands containing TEMPO fragments as receptor units for (bio)thiols are reported. The presence of free radical fragments of the ligand in the complexes was proved by using the electronic paramagnetic resonance (EPR) method. Among all the complexes, the Eu(III) complex turned out to be the most promising one as luminescence- and spin-probe for the detection of biogenic thiols. The EPR and fluorescent titration methods showed the interaction of the resulting complex with free Cys and GSH in solution. To study the practical applicability of the probes for the monitoring of AD in-vivo, by using the above-mentioned Eu(III)-based probe, the staining of the brain of mice with amyloidosis and Vero cell cultures supplemented with the cysteine-enriched medium was studied as well as the fluorescence titration of Bovine Serum Albumin, BSA (as the model for the thiol moieties containing protein), was carried out. Based on the results of fluorescence titration, the formation of a non-covalent inclusion complex between the above-mentioned Eu(III) complex and BSA was suggested.     

New approach to chemical modification of PIM-1 for gas separation membranes

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