Direct Hydroxylation of Methyl Benzoate to Methyl Salicylate by Using New Pd Membrane Reactor

The direct hydroxylation of methyl benzoate was carried out using a newly developed Pd membrane reactor in which the active oxygen species is formed on the surface of Pd by the reaction between oxygen gas and the active hydrogen atoms that permeate through the Pd membrane from the opposite side. By using this Pd membrane reactor system, methyl salicylate showed a 4.7% yield at 423 K. The reaction mechanism was clarified based on the distribution of by-products.