Highly Active PEG-Modified HZSM-5 Zeolite for Cyclohexene Hydration to Cyclohexanol

Cyclohexanol is a key intermediate in the preparation of nylon materials. However, commercial catalysts for the preparation of cyclohexanol have low catalytic activity. We developed a method for the production of HZSM-5 zeolites by hydrothermal synthesis using the structural additive poly(ethylene glycol) (PEG) as a modifier. The amount of PEG added had an effect on the specific surface area and Bro̷nsted acid sites of the zeolites. The HZSM-5 zeolite prepared by PEG addition of 1.5 g had a large specific surface area, more Bro̷nsted acid sites, and a rich pore structure, which facilitated the exposure of more Bro̷nsted acid sites to HZSM-5 and the diffusion process of cyclohexene and cyclohexanol. Under the optimized reaction conditions of a reaction temperature of 130 °C, a reaction pressure of 0.95 MPa, a reaction time of 4 h, a cyclohexene to water volume ratio of 1:1, a stirring speed of 600 rpm, and a catalyst dosage of 35 wt %, the catalytic performance of 1.5 g of PEG-modified HZSM-5 was better, with 15.93% cyclohexene conversion and 99.35% cyclohexanol selectivity. The PEG-modified HZSM-5 zeolite still maintained a high catalytic performance after five reuse cycles.