Selective oxidation of benzyl alcohol with hydrogen peroxide over reaction-controlled phase-transfer catalyst

The oxidation of benzyl alcohol (BzOH) to benzaldehyde (BzH) catalyzed by reaction-controlled phase-transfer catalyst with hydrogen peroxide as the oxidant has been investigated. In this system, the catalyst [C7H7N(CH3)3]3PMo4O16 (BTPM) can be recovered easily after the homogeneous reaction finished. It was disclosed that the countercation of catalyst, reaction solvents, molar ratio of H2O2 to BzOH and pH value of system not only affected the conversion of BzOH, but also determined the catalytic action of catalyst. Under the optimal conditions, the selectivity of BzH was not less than 99%, and the conversion of BzOH based on H2O2 reached 92.8%. The results of the catalyst recycle indicated that the catalyst exhibited high stability.