Manganese dioxide and N-hydroxyphthalimide. An effective catalytic system for oxidation of nitrotoluenes with molecular oxygen

Abstract

The inexpensive manganese dioxide has been proven to be an efficient auxiliary for oxidizing N-hydroxyphthalimide (NHPI) to form the phthalimide N-oxyl radical via reduction and reoxidation. The combination of manganese dioxide and NHPI could catalyze effectively the oxidation of nitrotulenes by molecular oxygen. Thus, the oxidation of p-nitrotoluene with molecular oxygen (0.4 MPa) in the presence of manganese dioxide (10 mol%) and NHPI (10 mol%) in acetic acid at 110° for 4 h proceeded with 97 % conversion, and gave p-ni-trotoluene in 89 % isolated yield. © 2007 Wiley-VCH Verlag GmbH & Co. KGaA.