Study of alkene epoxidation in the presence of extruded silicalite titanium

Main features of liquid-phase epoxidation of propylene, allyl chloride, and allyl alcohol by aqueous solution of hydrogen peroxide in the presence of extruded titanium silicalite in methanol medium have been investigated. The effects of the solvent, the initial ratio of the organic substrate: hydrogen peroxide, and temperature on the yield of main products and by-products were elucidated. Based on the obtained features the conditions for the synthesis of propylene oxide, epichlorohydrin, and glycidol in a laboratory continuous set-up were established.     

Oxidative carbonylation of alkynes in self-oscillating mode. Effect of the nature of substrates on the dynamic behavior of reaction system

The oxidative carbonylation of alkynes in the oscillation mode was studied. The influence of the nature of substrates, alkynes and alcohols, on the pattern of oscillations was considered. The role of oxidants, I₂ and H₂O₂, in this process was demonstrated. The reaction network of the process was formulated, and four hypothetical mechanisms were selected.     

Kinetics of cyclohexene oxidation by <Emphasis Type="Italic">p</Emphasis>-quinones in aqueous-organic solutions of cationic palladium(II) complexes

A kinetic study of cyclohexene oxidation by p-quinones in water-acetonitrile solutions of cationic Pd(II) complexes has been carried out for the first time. The observed kinetic regularities (dependence of the initial rate on the HClO₄ and p-benzoquinone concentrations) and the shape of the kinetic curves differ radically from those for the chloride systems. The unsteady-state process can be described only under the assumption that complexes of reduced palladium species with quinones are catalytically active forms. The role of solvated palladiumcarbenium ions in particular steps of the mechanism is discussed.     

Coupled processes in carbon monoxide oxidation: Kinetics and mechanism of CO oxidation by oxygen in PdX<Subscript>2</Subscript>-organic solvent-water systems

PdX₂-organic solvent-water solutions, where X = halide (preferably bromide or iodide) and the organic solvent is 1,4-dioxane or tetrahydrofuran, are suggested as catalytic systems for CO oxidation. A number of coupled processes take place in these systems. The kinetics and mechanism of CO oxidation by oxygen in the PdI₂-LiI-1,4-dioxane-water system are reported. Cyclohexene hydrocarboxylation into cyclohexanecarboxylic acid can be carried out as part of the coupled process occurring in the PdBr₂-tetrahydrofuran-water system.