Involvement of Free Radicals in the Catalytic Oxidation of Phenol in Aqueous Solution.

摘要

Aqueous-phase catalytic oxidation of phenol over supported copper oxide was studied from 369to 452degrees K and 14.7to 250psig oxygen pressure in batchwise mode. The reaction involves an induction period and a steady-state activity regime. The initial rate is first order in phenol and in oxygen;the steady-state rate is first order in phenol and one-half order in oxygen. Free radical involvement in the heterogeneously catalyzed oxidation of phenol was established. Reaction networks are similar for the heterogeneously and homogeneously catalyzed oxidation of phenol as far as quinones. Intermediates such as organic acids,which are observed in homogeneous oxidation,were not observed in the heterogeneously catalyzed oxidation. Aqueous-phase heterogeneously catalyzed oxidation removes organic carbon,initially charged as phenol,from solution efficiently at moderate temperatures and pressures. The less severe conditions required for aqueous-phase catalytic oxidation of organics make it appear much more economical than non-catalyzed wet air oxidation. (Katzer-Delaware)