Application of Chromium-Arene Complexes in the Organic Synthesis. Efficient Synthesis of Stilbene Phytoalexins

Planar chiral ⁶-arene-Cr(CO)₃ complexes represent highly valuable building blocks for the diastereo- and enantioselective synthesis. Their employment as synthons offer new and unique opportunities for the stereoselective multistep synthesis of complex natural products. The strategy of novel efficient synthesis of stilbene phytoalexins was based on arene chromium chemistry and the chemical and stereochemical effects of the metal unit on the reactivity of complexed arene ligand and stereochemical features of such compounds. Two variants for the construction of the trans-stilbene and diarylethanol framework via facilitated benzylic deprotonation of an ⁶-benzene-Cr(CO)₃ complex and subsequent coupling with para-anisaldehyde in an aldol-type or a Wittig–Horner reaction were suggested.     

Physicochemical Grounds for Application of Schungite for Neutralization of 1,1-Dimethylhydrazine in Wastewater

Chromatography–mass spectrometry and MALDI mass spectrometry have been used to study the interaction of 1,1-dimethylhydrazine and products of its oxidation with the surface of mineral schungite in aqueous solutions. A comparative analysis has been performed for organic compounds contained in initial and equilibrium 1,1-dimethylhydrazine solutions brought in contact with schungite, as well as compounds desorbed from the modified surfaces of the mineral and its inorganic components. The analysis has revealed the efficiency of schungite as a low-cost and environmentally friendly sorbent capable of catalyzing the profound oxidation of 1,1-dimethylhydrazine and products of its transformation to nontoxic low-molecularmass substances. Environmentally safe methods have been proposed for the regeneration of used schungite.     

Synthesis of amorphous homopolymer of perfluoropropyl vinyl ether at a high pressure

A high-molecular-weight amorphous homopolymer of perfluoropropyl vinyl ether was synthesized by radical polymerization at a pressure from 500 to 1200 MPa. The polymer properties were studied and reported.     

Thermal resistance of composites based on nanodispersed aluminum

Thermolysis of low and high molecular aliphatic carboxylated compounds in composite systems based on nanosized aluminum were studied by the thermal desorption mass spectrometry. The conditions for maximal separation of the thermolysis products and their composition were determined. The kinetic parameters of thermal desorption and thermal degradation of the modifiers were calculated. Differences in the thermal stabilities of the polymer composites based on nanosized aluminum and different modifiers (carboxylated divinyl and divinyl nitrile oligomers) were presented.     

An oscillatory system with a magnetic-fluid viscoinertial element

Results of measuring the damping factor of an oscillatory system the viscoinertial element of which is represented by a magnetic fluid filling a U-shaped glass tube are considered. The role of elasticity is played by an air-filled cavity that is formed in one of the tube legs under the piezoelectric plate attached to its end and serving for oscillation reception. A method of measuring the oscillation damping factor is proposed, and the results of these measurements are used to determine the shear viscosity of magnetic fluid samples as a function of magnetic field strength.     

Electrochemical and chemical reduction of β,γ-unsaturated δ-cyclosulfonates

Conclusions The electroreduction of sultones in DMF results in the predominant cleavage of the C-O bond with the formation of the salt of the unsaturated sulfonic acid; catalytic hydrogenation also proceeds by the same scheme.Deceased.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2618–2620, November, 1978.     

The elasticity of a magnetic-fluid membrane

For a magnetic-fluid membrane, the critical pressure drop is determined experimentally using thermodynamic and hydrostatic methods. It is found that the value of the critical pressure drop calculated from the data of the thermodynamic method exceeds by ～30% the value of this parameter measured by the hydrostatic method. The overstated value of the critical pressure drop obtained using the indirect thermodynamic method is explained by the approximate nature of the analytical model lying at its basis, which does not take into account the relaxation character of pondermotive elasticity. The static and thermodynamic coefficients of pondermotive elasticity of a magnetic-fluid membrane sample are calculated, and the results are used to estimate the membrane displacement by the moment of its breakage.     

Magnetophoresis of Microparticles in a Magnetic Fluid

Russian Physics Journal - An experimental setup is developed for studying magnetophoresis in a layer of a magnetic fluid several millimeters thick by the method of light transmission and...     

Experimental investigation of an air-magnetic-liquid resonator

Experimental results obtained by studying a vibratory system in which a magnetic liquid playing the role of a mass shuts off the cross section of a tube under the effect of a magnetic field and is spring-loaded by an air cavity and elasticity of ponderomotive type are discussed. An expression for the resonant frequency of vibrations is derived with allowance for both types of elasticity. The expression agrees well with the experimental data.