Catalytic air oxidation of cyclooctene using cis-[MoO2(SAL-SH)(DMF)] (SAL-SH = salcylidene salicyloyl hydrazinato-) and its zeolite-Y encapsulated composite

Oxidation of cyclooctene to cyclooctene epoxide using cis-MoO2(SAL-SH)(DMF) and its zeolite-Y encapsulated composite as catalysts is reported. The per cent conversion into epoxide was 68% at 60 degrees C under 0.1 mmol of cis MoO2(SAL-SH)(DMF), 0.3 mmol of cyclooctene and under oxygen saturated condi tions. The turnover with respect to Mo in the complex is eight. The percent conversion improved to 75% and the turnover increased nine times when comp lex-NaY composite is used under the same conditions. The oxidation reaction showed first order dependence with respect to the concentrations of cataly st and cyclooctene. The reaction is endothermic with an activation energy o f 25.8 kcal mol(-1). A reaction scheme for oxidation of cyclooctene using c is-MoO2(SAL-SH)(DMF) is proposed and the higher activity observed with comp lex-NaY composite is attributed to absence of mu-oxo dimer formation in thi s case. The intermediate Mo(IV)O complex reacts with O-2, regenerating the parent Mo(VI)O, complex, which participates cyclically in the reaction; (C) 1999 Elsevier Science B.V. All rights reserved.