Molybdenum complex-catalysed epoxidation of unsaturated fatty acids by organic hydroperoxides Original Research Article

The catalytic activity of the molybdenum catalysts, molybdenum naphthenate, Mo(CO)6, H2[Mo2O4(ox)2(H2O)2]·4H2O·Me2CO, Mo(O)2(acac)2, and [Mo(O)2(SAP)(EtOH)], was investigated in the reaction of oleic acid epoxidation by organic hydroperoxides. A new highly efficient and selective system for the epoxidation of unsaturated aliphatic acids was developed with tert-butyl hydroperoxide (t-BuOOH) and the [Mo(O)2(SAP)(EtOH)] complex. The epoxidation reaction of oleic acid shows 86.8% selectivity to 9,10-epoxystearic acid at 67% conversion of t-BuOOH. Routine kinetic measurements were performed to determine the reaction orders with respect to t-BuOOH and the catalyst. They are 1.00±0.05 and 0.51±0.05, respectively. The activation energy and enthalpy, Ea=99±4 kJ mol−1 and ΔH=96±4 kJ mol−1, were calculated from the temperature dependences. The results allowed us to propose a reaction mechanism whose outline is consistent with the generally accepted mechanism of the catalytic epoxidation of olefins by organic hydroperoxides.