Oblique collision of a plane-polarized Alfvén discontinuity and a slow shock wave propagating in opposite directions in magnetohydrodynamics

Collision of plane fronts of a plane-polarized Alfvén discontinuity and a slow shock wave propagating in opposite directions at a certain angle is considered within the framework of an ideal magnetohydrodynamic model. The initial state of an infinitely conducting medium at rest with a frozen-in magnetic field is assumed to be given. Calculations are carried out for various values of the shock wave Mach number and the magnetic field strength using a special software which makes it possible to find an exact solution of the Riemann problem of breakdown of a discontinuity between the states downstream of the interacting waves by means of a computer. The wave flow structure is investigated and a bifurcation map of flow restructuring is constructed. Domains of the initial parameters for which the interaction differs qualitatively are distinguished. The parameters of the medium and magnetic field are found as functions of the angle between the colliding discontinuities and the inclination of the magnetic field. The results obtained may be used in investigations of magnetic reconnection.     

Baeyer–Villiger oxidation of <Emphasis Type="Italic">N</Emphasis> <Superscript>1</Superscript>,<Emphasis Type="Italic">N</Emphasis> <Superscript>3</Superscript>,2-triaryl-6-hydroxy-6-methyl-4-oxocyclohexane-1,3-dicarboxamides

Baeyer–Villiger oxidation of N¹,N³,2-triaryl-6-hydroxy-6-methyl-4-oxocyclohexane-1,3-dicarboxamides with 30% hydrogen peroxide in acetic acid afforded 2-(4-aryl-3-carbamoyl-2-methyl-5-oxooxolan-2-yl)acetic acids.     

Synthesis and Biological Activity of 2-Aryl-4-hydroxy-4-methyl-6-oxocyclohexane-1,3-dicarboxamides

Russian Journal of General Chemistry - The reaction of unsubstituted acetoacetamide with aromatic aldehydes in ethanol in the presence of piperidine gave...     

Formation of Polymer Nanolayers with Special Properties at Polymer Surfaces

A principal possibility of the utilization of polymer peroxides for the modification of polymer surfaces that provides an immobilization of the tailored quantity of peroxide groups at them has been established. The processes of polymer surface activation with following “grafting from” or “grafting to” utilizing immobilized peroxide groups has been studied using a FTIR-ATR spectroscopy, ellipsometry and measurements of contact angles. The proposed technique of polymer surface activation is based on the universal ability of carbon chain polymer to participate the free radical reactions.     

Erratum to: “A highly efficient white-light-emitting diode based on a two-component polyfluorene/quantum dot composite”

Optics and Spectroscopy -     

Copper-containing catalysts for the oxidative dehydrogenation of organic compounds

A method of doping magnesium aluminum hydrotalcites, which are precursors for oxidative dehydrogenation oxide catalysts of various compositions, with copper(II) was developed, and copper(II)-containing oxide catalyst samples were synthesized. The catalytic properties of these catalysts were studied in the oxidative dehydrogenation of ethane, propane, and hexane. The conversion of ethane into ethylene on the copper-containing catalysts was established to proceed with high selectivities (90?C97%) and at low temperatures (400?C450°C).     

1,2 → 1,1-Migration of Silyl Group. Formation of 1,1-Bis(dichloromethylsilyl)-2-chloroethane in Catalytic Hydrochlorination of 1,2-Bis(dichloromethylsilyl)ethylene

Hydrochlorination of 1,2-bis(silyl)ethylenes of the general formula Me_nCl_3-n SiCH = CHSiMe_n· Cl_3-n , where n = 0-3, in the presence of FeCl₃ was carried out. By NMR spectroscopy it was shown that in the case of the MeCl₂Si derivative the major product is 1,1-bis(silyl)chloroethane and the minor product is its isomeric 1,2-bis(silyl)chloroethane (4:1). A reaction scheme is proposed, that includes isomerization of the intermediate bis(silyl)ethyl cation.     

Synthesis of New Fluorinated Derivatives of Quinolinecarboxylic Acids

Ethyl esters of 1-(7-Z-1-ethyl-6-fluoro-4-oxo-1,4-dihydroquinoline-3-carbamoyl)-5-X-6,7,8-trifluoro-4-oxo-1,4-dihydroquinoline-3-carboxylic acids (X = H, F; Z = pyrrolidino-, piperidino-, hexamethylenimino-, morpholino-, thiomorpholino-) have been synthesized by the interaction of quinolone-3-carboxylic acid hydrazides with ethyl esters of 3-ethoxy-2-(polyfluorobenzoyl)acrylic acid . It was shown possible to cyclize intramolecularly the esters obtained with the formation of 1,3,4-oxadiazino[6,5,4-i,j]quinoline derivatives.     

Mechanism of the oxidative carbonylation of terminal alkynes at the ≡C-H bond in solutions of palladium complexes

The formation mechanism of the active catalyst in the oxidative carbonylation of terminal alkynes at the ≡C-H bond has been investigated for the catalytic system Pd(OAc)₂-PPh₃-p-benzoquinone (Q)-MeOH. It has been demonstrated by NMR spectroscopy, X-ray crystallography, and kinetic measurements that the catalytically active palladium is in the oxidation state 0 and is bound into complexes stabilized by p-benzoquinone (PdL₂Q, where L = PPh₃). A mechanism is suggested for the catalytic process, which includes the formation of the complex PdL₂Q, the oxidative addition of the alkyne to this complex at the ≡C-H bond, the insertion of CO into the Pd-C bond, and steps in which hydride hydrogen is intramolecularly transferred to the p-quinone.