Catalytic air oxidation of cyclooctene using cis-[MoO 2(SAL-SH)(DMF)] (SAL-SH=salcylidene salicyloyl hydrazinato-) and its zeolite-Y encapsulated composite

Abstract

Oxidation of cyclooctene to cyclooctene epoxide using cis-MoO 2(SAL-SH)(DMF) and its zeolite-Y encapsulated composite as catalysts is reported. The percent conversion into epoxide was 68% at 60°C under 0.1 mmol of cis-MoO 2(SAL-SH)(DMF), 0.3 mmol of cyclooctene and under oxygen saturated conditions. The turnover with respect to Mo in the complex is eight. The percent conversion improved to 75% and the turnover increased nine times when complex-NaY composite is used under the same conditions. The oxidation reaction showed first order dependence with respect to the concentrations of catalyst and cyclooctene. The reaction is endothermic with an activation energy of 25.8 kcal mol −1. A reaction scheme for oxidation of cyclooctene using cis-MoO 2(SAL-SH)(DMF) is proposed and the higher activity observed with complex-NaY composite is attributed to absence of μ-oxo dimer formation in this case. The intermediate Mo(IV)O complex reacts with O 2, regenerating the parent Mo(VI)O 2 complex, which participates cyclically in the reaction.