Highly Enhanced Phenol Hydroxylation in [<i>h</i>0<i>h</i>]‐Oriented Fe–ZSM‐5 Membranes

Abstract

Abstract Catechol (CAT) and hydroquinone (HQ) are two important diphenol isomers with a variety of industrial applications. The hydroxylation of phenol catalyzed by transition metal (TM) substituted ZSM‐5 is an environmentally benign route for diphenol production, which is usually governed by intracrystalline diffusion. Therefore, the availability of highly oriented TM‐ZSM‐5 membranes and their utilization in an interphase membrane reactor can significantly promote the hydroxylation of phenol. The continuous and [ h 0 h ]‐oriented Fe–ZSM‐5 membrane on the porous α‐Al 2 O 3 was prepared using a new seeded growth method. Characterization was carried out by using SEM, XRD, UV/Vis, and EPMA techniques, which demonstrated that the [ h 0 h ]‐oriented membrane consists of Fe substituted ZSM‐5 crystal grains with an Si/Fe ratio of approximately 75. Compared with the catalytic performance of different sized Fe–ZSM‐5 grains loaded in the traditional slurry reactor, the [ h 0 h ]‐oriented Fe–ZSM‐5 membrane in the interphase membrane reactor showed significantly improved phenol conversion and selectivity for CAT and HQ due to the molecular path control in the zeolite membranes.