Formation of Cu-supported mesoporous silicates and aluminosilicates and liquid-phase oxidation of benzene catalyzed by the Cu-mesoporous silicates and aluminosilicates

Abstract

Mesoporous silicates (MCM-41 and Al-containing MCM-41) were applied to catalyst supports for liquid-phase benzene oxidation paying attention to their remarkable features, such as large surface area, ordered mesopores and high thermal stability. The MCM-41-supported Cu catalysts were prepared by the method of impregnation (Cu/MCM-41) and ion-exchange treatment (Cu–Na·MCM-41, Cu–H·MCM-41). The liquid-phase oxygenation of benzene to phenol over the MCM-41-supported Cu catalysts was studied using molecular oxygen as an oxidant and ascorbic acid as a reducing reagent for the Cu species. The MCM-41-supported Cu catalysts, particularly the Cu ion-exchanged H·MCM-41 (Cu–H·MCM-41), were more active than the corresponding Cu catalysts supported on SiO 2, TiO 2, MgO, NaZSM-5, NaY, or KL zeolites. The accumulation of hydrogen peroxide (H 2O 2) was confirmed during the liquid-phase oxidation of benzene catalyzed by the Cu-supported MCM-41.