Polymer Anchored Catalysts for Oxidation of Styrene Using TBHP and Molecular Oxygen

Catalytic oxidation of styrene was investigated for polymer anchored Cu(II) and Mn(II) complexes prepared by Schiff base tridentate ligand. The effect of different oxidants, tert-butyl hydroperoxide (TBHP) under atmospheric pressure and molecular oxygen (O-2) at high pressure in a batch reactor, were studied for maximum conversion of styrene and selectivity of styrene oxide product. The effect of various reaction parameters such as temperature, styrene to TBHP mole ratio, and catalyst amount were studied using TBHP as oxidant. The maximum conversion of styrene (87.3%) was obtained using Cu(II) complex, with maximum selectivity to styrene oxide (76.2%) at styrene to TBHP mole ratio of 1:3, 70 degrees C, and 25 mg catalyst. The O-2 oxidant showed maximum conversion of 45.5% at 80 degrees C and 0.5 MPa pressure, with a styrene oxide selectivity of 22.4%. The catalytic activity was improved to 70.0% by addition of TBHP as initiator during the use of O-2 oxidant. The Cu(II) catalyst showed better catalytic activity in comparison to Mn(II) catalyst using both TBHP and O-2 oxidant.