Instrumental neutron activation determination of gold in mineral raw materials using a californium neutron source

A facility using a californium neutron source and a method for the neutron activation analysis of gold were developed. The sensitivity of the determination is 0.1 g/t. The sources of random and systematic errors have been studied. It has been concluded that in prospection and evaluation of gold ore deposits, the traditional test tube analysis for gold may be replaced with the developed method.     

Adsorption of phenol and 2,4-dichlorophenol on carbon-containing sorbent produced from sugar cane bagasse

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Oxidation of carbon monoxide catalyzed by Pd(α,α-bipy)Cl2—CuCl2—C3F7COOH/γ-Al2O3: oscillations in the flow reactor

Russian Chemical Bulletin -     

Interaction of cationic chlorin photosensitizers with non-ionic surfactant Tween 80

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Phase composition of Mg—Al mixed oxides,their activity and selectivity in the ethanol condensation reaction

Layered hydroxides with a molar ratio of metals Mg: Al: M = 3: 1: 1 (M = Fe, Ce, Zr, Cr) were prepared and served as a basis to obtain the mixed oxides MgAlO_x, MgAlCrO_x, MgAlCeO_x, MgAlZrO_x, and MgAlCrO_x. Powder X-ray diffraction was used to study the phase composition of the oxides. It was suggested that the catalyst active surface is related to the presence of spineltype X-ray amorphous compounds. Ammonia adsorption was used to determine the total acidity, and deuterated acetonitrile adsorption was applied to estimate the strength of acid sites. The catalytic properties of complex oxides were studied in the ethanol condensation reaction. An attempt was made to correlate the catalyst activity and selectivity and the distribution of acid and base sites on the catalyst surface.     

Microwave-assisted conversion of lignin into aromatic compounds

Low-power (≤10 W) microwave radiation considerably reduces the initial temperature in the catalytic hydrocracking of lignin as compared to conventional thermal heating. The microwave-assisted catalytic transformation of lignin at 260-290°C under atmospheric pressure afforded in high yield C₆-C₁₀ aromatic and aliphatic hydrocarbons in addition to methoxyphenols and alkylated methoxyphenols. A correlation has been found between the activity of the catalyst (1% Pt/C) and the size of platinum metal particles.     

Carboxylation of 2-methylbutyn-3-ol-2 on Ag- and Cu-containing catalysts

The analysis of the products of direct carboxylation of 2-methylbutyn-3-ol-2 with carbon dioxide on Ag- and Cu-containing catalysts by ¹Н and ¹³С NMR and FTIR spectroscopy showed that the desired 4-hydroxy-4-methylpent-2-ynoic acid did not form under the given conditions; instead, the triple bond of the substrate decomposed, and two polyfunctional acids formed: 4-hydroxy-4-methyl-3-oxopentanoic and 3,4-dihydroxy-4-methylpent-2-enic (the latter is the result of the keto-enol rearrangement of the former keto acid).     

Ecotoxicity of organic stabilizers for metal nanoparticles

Russian Journal of Organic Chemistry -     

Spectral studies of catalysts of oxidative dehydrogenation of dimethyl ether to dimethoxyethane

Spectral methods (diffuse reflectance infrared Fourier transform spectroscopy, EPR) are used to study the adsorption of dimethyl ether and oxygen on a catalyst of oxidative dehydrogenation of dimethyl ether to dimethoxyethane. The formation of O ₂ ^? superoxide paramagnetic species is revealed. A mechanism of the formation of dimethoxyethane is proposed.