Some peculiarities of the photocatalytic oxidation of hydrocarbons by hydrogen peroxide on a heterogeneous catalyst: Titanium silicalite

Data on the effect of the type and intensity of irradiation on the basic characteristics of the process and distribution of products of catalytic liquid-phase oxidation of hydrocarbons were obtained using as an example the oxidation of n-dodecane by hydrogen peroxide aqueous solutions on the heterogeneous catalyst: titanium silicalite.     

Interaction between gaseous ozone and crystalline potassium bromide

The formation of nonvolatile products of the oxidation of a bromide ion during the interaction between gaseous ozone and powdered crystalline KBr is studied. It is found that potassium bromate KBrO₃ is the main product of the reaction. The influence of major experimental factors (the duration of ozonation, the concentration of ozone, the humidity of the initial gas, and the temperature) on the rate of formation of bromate is studied. The effective constants of the formation of bromate during the interaction between O₃ and Br^– in a heterogeneous gas–solid body system and in a homogeneous aqueous solution are compared.     

Oxide talum-containing catalysts of ozone decomposition and methane oxidation

The oxidation of manganese ions is shown to occur in ozone decomposition on manganese-containing catalyst, leading to the deactivation of a sample. The structure of the iron-containing catalyst does not change, ensuring its high stability during ozone decomposition in a dry gas flow at room temperature, conducted in the region of inner diffusion with an activation energy of 15.5 ± 0.7 kJ/mol. The presence of manganese cations in the intermediate stages of reduction is found to increase their activity in the reaction of deep methane oxidation.     

Correlation between the size and photoluminescence spectrum of quantum dots in InAs-QD/GaAs

A computational method for determining the real sizes of quantum dots based on the data of atomic force microscopy (AFM) is suggested. It is shown that the experimentally observed measurement error (for the AFM method) of the sizes of the pyramidal quantum dots with a base edge of a ～ 30–46 nm, stemming from convolution, is approximately equal to a quarter of the curvature radius of the AFM probe. Calibration curves of the dependence of the photoluminescence-peak positions of InAs-QD/GaAs heterostructures (in the range 900–1800 nm) on the sizes of the quantum dots measured with the probes whose curvature radii were from from 10 to 100 nm are established.     

Convenient synthesis of 1-hydrazinylanthracene-9,10-diones

Russian Journal of Organic Chemistry - An efficient procedure has been proposed for the synthesis of previously unknown 1-hydrazinylanthraquinones containing acyl and/or ester fragments convenient...     

Heat effect during the low-temperature oxidation of nickel nanoparticles in a porous matrix

A model of the heat-generating reaction of the low-temperature oxidation of nickel nanoparticles in nickel-supported catalysts is discussed. We use the continuous measurement of magnetization to estimate the heat effect of the reaction, allowing us to measure the heating of nickel nanoparticles in the support matrix, due to the temperature dependence of magnetization.     

Conversion of C<Subscript>2</Subscript>-C<Subscript>4</Subscript> alcohols over copper-containing catalysts on carbon and fluorocarbon fibers

Carbon and fluorocarbon fibers were used as carriers for the preparation of copper catalysts from copper oxalate as precursor. The catalytic properties of catalyst were studied in the reaction of the dehydrogenation of C₂-C₄ alcohols by the pulsed microcatalytic method. The effect of the copper content in the catalyst, the reaction temperature on the degree of conversion, and the relation of the reaction channels were studied. The electron microphotographs were obtained, specific surfaces were measured, and X-ray pictures and infrared spectra of catalysts were taken. The activity of the catalysts on the carbon and fluorocarbon fibers in the dehydration-dehydrogenation reactions of C₂-C₄ alcohols was comparatively estimated. It was shown that the selectivity of the products from the dehydrogenation reaction is higher for the Cu-fluorocarbon fiber catalyst.     

Femtosecond X-ray free-electron lasers: A new tool for studying nanocrystals and single macromolecules

A brief overview of the design of femtosecond X-ray free-electron lasers (XFEL), characteristics of the emitted X-ray pulses, and potentialities of XFEL are presented. A concise analysis of the problems in modeling X-ray scattering patterns produced by ultraintense radiation sources is given.