An eco-friendly approach to the cyclohexane oxidation catalyzed by manganese porphyrins: Green and solvent-free systems.

Graphical abstract Total yields (cyclohexanol + cyclohexanone) up to 90% were achieved in cyclohexane oxidation using ethyl acetate, which is an efficient green solvent to replace dichloromethane. Abstract The selective cyclohexane oxidation to cyclohexanone and cyclohexanol based on a green strategy has been a challenge. A new manganese porphyrin [MnIII(T2,4,5TMPP)Cl] was prepared and its activity and selectivity as a catalyst were studied together with the classical manganese porphyrin [MnIII(TPP)Cl] using green solvents (dimethyl carbonate or ethyl acetate) and solvent-free systems. The effects of the solvent (or its absence), oxidant, and co-catalyst were investigated. Under the studied conditions, the new catalyst showed a higher selectivity for cyclohexanol (above 78%) in solvent-free systems compared to the [MnIII(TPP)Cl]. The highest total yield of the products (89%) was observed in ethyl acetate/PhIO/water system. [ABSTRACT FROM AUTHOR]