Pd–silicalite-1 composite membrane reactor for direct hydroxylation of benzene to phenol

Pd–Sil-1 composite membrane consisting of 5 μm Pd membrane anchored by multi-leg protrusions to the 2 μm Sil-1 intermediate support layer was prepared from Pd/Sil-1 co-seeds. The membrane displays good permeation flux and is stable for 2.5 weeks of permeation and reaction studies. The Pd–Sil-1 composite membrane was employed for direct hydroxylation of benzene to phenol. Reaction parameters including temperature and H2/O2 molar feed ratio were investigated for their effects on benzene conversion, phenol yield, water generation and hydrogen efficiency.