Peroxyacetic acid oxidation of olefins and alkanes catalyzed by a dinuclear manganese(IV) complex with 1,4,7-trimethyl-1,4,7-triazacyclononane

Natural terpenes, (-)-limonene and (+)-carvone, can be epoxidized by peroxyacetic acid (PAA) at room temperature if a dinuclear manganese(IV) complex with 1,4,7-trimethyl-1,4,7-triazacyclononane (L), [Mn2L2O3] [PF6](2), is used as a catalyst. The total yield of the epoxides based on the consumed olefins are 97 and 95%, respectively. A kinetic study of the dec-1-ene and cyclohexane oxygenations including the investigation of their simultaneous competitive oxidation was carried out. The olefin epoxidation rate does not depend on dec-1-ene concentration and the dec-1-ene concentration does not affect the rate of cyclohexane oxidation. The cyclohexane oxidation rate is proportional to the alkane concentration. The kinetic analysis led to the conclusion that two species X-1 and X-2 are generated in the system, and there is no their mutual interconversion. The rate equation for the dec-1-ene epoxidation was proposed: W = k (+1)[cat][PAA], where cat is the initial manganese complex or its derivative, and the constant was determined: k(+1) = 3.5 mol(-1) dm(3) s(-1). Species X-1 is apparently an effectively epoxidizing manganese peroxo derivative whereas species X-2 is an alkane hydroxylating manganese oxo complex.