Kinetics and Mechanism of Thermal Decomposition of 1-(Dinitromethyl)-3-R-1H-1,2,4-triazoles

Russian Journal of General Chemistry - Kinetic regularities and the mechanism of thermal decomposition of 3-substituted 1-(dinitromethyl)1H-1,2,4-triazoles in the solid phase and in dibutyl...     

Electrochemical oxidation of dyes on oxide lead anode with the involvement of active oxygen species

Kinetics and selectivity of oxidation of dyes (Methyl Orange and Chrome Dark Blue) on a lead dioxide (Pb/PbO₂) anode at various current densities, substrate concentrations, and pH values with the use of various active oxygen species was studied. It was shown that the electrochemical oxidation of dyes on the Pb/PbO₂ anode occurs rather effectively under the chosen conditions. The mineralization efficiency in 5 h was 51 to 89.5 and 93 to 100% for, respectively, Methyl Orange and Chrome Dark Blue, depending on the electrolysis conditions.     

Electrocatalytic Oxidation of Organic Pollutants on Boron-Doped Diamond and Ti–Ru Oxide Anodes in Sulfate Medium

Electrochemical oxidation for degradation of industrial dye Methyl Orange in aqueous sulfate solutions with various electrocatalytic materials: boron-doped diamond electrode and electrode based on titanium and ruthenium oxides. The influence exerted by the main working parameters of electrolysis (current density, concentration of Methyl Orange, pH) on the discoloration efficiency and on the chemical oxygen demand (COD) was examined. It was shown that an increase in the current density and a decrease in the pollutant concentration improve the process efficiency. However, this leads to an increase in the specific electric energy consumption per unit mass of COD. It was found that the boron-doped diamond electrode is a more efficient electrocatalytic material, compared with electrode based on titanium and ruthenium oxides. At low concentrations of Methyl Orange (<50 mg L^–1), there exists the possibility in principle of using the electrode based on titanium and ruthenium oxides not only for discoloration, but also for making lower the COD level.     

Thermal Decomposition of 3-Nitro-1-nitromethyl-1,2,4-1H-triazole in Solution

The thermal decomposition of 3-nitro-1-nitromethyl-1,2,4-1H-triazole in 1% solution in phenyl benzoate proceeds homolytically with initial rupture of the CH₂-NO₂ bond. Activation parameters of the process were E _a = 172.6 kJ/mol, log A = 14.25. The initial basic pathway of fragmentation of the molecule under electron impact coincides with the first step of thermal decomposition, which is in agreement with X-ray structural and calculated quantum chemical data on bond stability in the molecule.     

Synthesis of derivatives of 2-hydroxyimino- and 2-alkoxyimino-3-(acylhydrazono)butanoic acids

Esters andN-methylamides of 2-hydroxyimino- and 2-alkoxyimino-3-(acylhydrazono)-butanoic acids were synthesized by condensation of acyl hydrazines with the corresponding alkyl 2-hydroxyimino- and 2-alkoxyimino-3-oxobutanoates andN-methyl-2-methoxyimino-3-oxobutanamide. The compounds obtained are analogs of strobilurins, fungicidal antibiotics. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 499–504, March, 1999.     

Fluxbrane and S-brane solutions related to Lie algebras

We overview composite fluxbrane and special S-brane solutions for a wide class of intersection rules related to semi-simple Lie algebras. These solutions are defined on a product manifold R* × M ₁ × ... M ₁ × ... ×M _n which contains n Ricci-flat spaces M ₁, ..., M _n with 1-dimensional R* and M ₁. They are governed by a set of moduli functions H _s , which have polynomial structure. The powers of polynomials coincide with the components of the dual Weyl vector in the basis of simple coroots.     

Effect of additive polyfunctional substituents on the thermal decomposition rate of R1,R2,R3-nitromethanes

Kinetics of thermal decomposition of polyfunctionally substituted nitromethanes has been studied by manometric method as well as IR and chromato-mass spectrometry. Activation parameters of the ratelimiting stage of C-NO₂ homolysis have been determined. The rate constant and the activation energy are correlated with additive steric constants of the substituents; this enables prediction of reactivity (thermal stability) of the unstudied mononitrocompounds which decompose with the break of C-NO₂ bond.