Copper precipitation from sulfate solutions with calcium carbonates

Mechanism of interaction of copper sulfate with natural calcium carbonates, responsible for low residual copper concentrations in solutions and for the behavior of open and closed systems in storage is considered.     

Direct anodic oxidation ofp-methoxytoluene in methanol. The effect of electrolysis conditions

The effect of anions of the supporting electrolyte (F^–, dialkylphosphate, TsO^–, and BF ₄ ^– and other electrolysis conditions (anode material, temperature, substrate concentration) on the selectivity of the direct anodic oxidation ofp-methoxytoluene in methanol into 4-methoxybenzaldehyde dimethylacetal was studied. The highest selectivity was obtained in the presence of fluoride anion.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 524–527, March, 1995.This work was financially supported by the Ministry of Science, High School and Technical Policy of the Russian Federation within the scope of the State scientific-technical program Ecologically harmless processes of chemistry and chemical technology (project No. 1.140 Low-tonnage chemical products) and by the International Science Foundation (Grant Ch-2-1246-0923).     

Electrooxidative coupling of salts of nitro compounds with halide,nitrite, cyanide,and phenylsulfinate anions

Electrolysis of salts of primary and secondary nitro compounds (nitroethane, 1- and 2-nitropropanes, nitrocyclohexane, and nitrocycloheptane) in the presence of excess halide, nitrite, cyanide, and phenylsulfinate anions under undivided and divided amperostatic electrolysis conditions in a two-phase medium (CH₂Cl₂/H₂O) produces geminal nitrohalides (35–85% yields), dinitro compounds (15–51%), nitronitriles (6–27%), and nitrosulfones (50–70%). The salts of secondary nitro compounds form the products of oxidative coupling with halide and phenylsulfinate anions under the undivided electrolysis conditions. In all other cases, divided electrolysis is required. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1539–1546, July, 2005.     

Time-resolved nonlinear surface plasmon optics

A new surface-sensitive method of time-resolved optical studies is proposed. The method consists in the independent excitation of several surface electromagnetic waves (SEW) by two laser femtosecond pulse beams with varied time delay Δτ and distance Δr between corresponding excitation regions on the surface. To fulfill the phase-matching condition for plasmon-photon coupling, metal grating is used. Due to nonlinear plasmon interaction, the optical radiation with ω₁ + ω₂ and 2ω₁ ? ω₂ (where ω₁, ω₂ are corresponding laser beam frequencies) is generated. The intensity of this nonlinear response versus Δτ and Δr are studied. The direct measurements of the SEW temporal properties are presented. Experiments of this type are important for the development of femtosecond surface plasmon optics.     

Pole contributions in semileptonic decays of D mesons

The contributions of the axial-vector and vector resonance states to D → P(V)l $\bar \nu$ _l decays are investigated on the basis of phenomenological chiral Lagrangians. It is shown that inclusion of such intermediate states improves agreement with experimental data.     

Nonempirical calculation of structural,electric and spectral characteristics of diprazine

Calculations of IR spectra, dipole moments, atomic charges, and structural characteristics of three forms of diprazine (molecular, cation and dication) were carried out. Changes in the studied characteristics in going from one form to another were analyzed.     

One-pot synthesis of substituted styrenes from vicinal dibromoalkanes and arylboronic acids

Dehydrobromination of vicinal dibromoalkanes in systems comprising 1,2-dimethoxy-ethane, N-butyl-N′-methylimidazolium tetrafluoroborate (or tetrabutylammonium bromide), and a base with subsequent palladium-catalyzed cross-coupling of the thus formed bromoalkenes with arylboronic acids furnished substituted styrenes. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 116–123, January, 2007.     

Degradation of physicomechanical properties of epoxy nanocomposites with carbon nanotubes upon heat and humidity aging

The dependence of the physicomechanical properties of epoxy nanocomposites subjected to heat and humidity aging on the type of covalently functionalized carbon nanotubes and on the uniformity of their distribution in the epoxy matrix was studied. Two types of carbon nanotubes were used: those modified with carboxy and amide groups. The elastic modulus, bending deflection, and ultimate bending strength for the initial epoxy nanocomposites with carbon nanotubes and for those subjected to heat and humidity aging were determined. The epoxy binders modified with carboxylated carbon nanotubes are more resistant to the action of aging factors. The presence of aggregates of carboxylated carbon nanotubes in the epoxy matrix positively influences the preservation of physicomechanical properties of the composite subjected to heat and humidity aging. Microscopic examination revealed structural features of the epoxy nanocomposite and their effect on the resistance of the composite to the heat and humidity aging.