On the membrane reactor concept for one-step hydroxylation of benzene to phenol with oxygen and hydrogen

The one-step hydroxylation of benzene to phenol with oxygen and hydrogen is a promising process, but there are severe challenges associated with the low phenol production. It was reported that the reaction can be greatly promoted by the simultaneous use of a dense palladium membrane as a catalyst and as a hydrogen distributor. We also carried out this reaction concept with palladium membranes under different reaction conditions, but found that the palladium membranes were almost inert for both the target reaction and the benzene combustion. This work summarized and compared among the literature results as well as ours, investigating the effects of the membrane preparation method and the combustion of hydrogen and benzene. The arguments on the mechanism and feasibility of the membrane concept were given in detail.