Manganese nanocatalyst and N-hydroxyphthalimide as an efficient catalytic system for selective oxidation of ethylbenzene, cyclohexene and oximes under aerobic condition

Abstract

The catalytic activity of the nano-manganese-catalyst in the aerobic oxidation of ethylbenzene, cyclohexene and oximes were evaluated without the need of any reducing agent, using N-hydroxyphthalimide (2-Hydroxy-1H-isoindole-1,3-dione; NHPI) under oxygen pressure. The oxidation of ethylbenzene and cyclohexene to acetophenone and 2-cyclohexene-1-one using N-hydroxyphthalimide (2-Hydroxy-1H-isoindole-1,3-dione; NHPI) under oxygen atmosphere in the presence of a SiO2/Al2O3-supported manganese catalyst occurs with conversions of 95 and 99% and selectivities of 99%. The supported manganese is also a suitable and efficient catalyst for the oxidative deprotection of oximes to the corresponding carbonyl compounds. A mild and efficient method has been optimized for manganese catalysts by considering the effect of various parameters such as the reaction time and the amount of catalyst, the temperature and the reusability of the catalyst after several runs without modification. Moreover, some possible mechanisms for the oxidation of ethylbenzene, cyclohexene and oximes have been proposed.