Effect of promoters on the catalytic activity of MCM-41 with high copper content in benzene hydroxylation

Cu-MCM-41 with a high copper content up to 26.0% showed excellent catalytic activity in the direct hydroxylation of benzene with hydroperoxide. The effects of various kinds of heteroatoms on the catalytic activity were studied. The introduction of a small amount of acidic promoters such as B and Al can enhance phenol selectivity to 100%. Some redox promoters such as V and Cr increase the conversion of benzene slightly, whereas other elements such as Ti and Zr inhibit the catalytic activity of catalysts. The reasons for these influences were briefly discussed according to the radical mechanism.