Reaction kinetics and mechanism for hydration of cyclohexene over ion-exchange resin and H-ZSM-5

摘要

The kinetics of liquid-phase cyclohexene hydration over ion-exchange resin and H-ZSM-5 were, respectively, investigated in a batch autoclave reactor. In order to identify the reaction mechanism involved in the heterogeneous cyclohexene hydration, a pseudo-homogeneous (PH) model and three heterogeneous models based on the Langmuir-Hinshelwood-Hougen-Watson (LHHW) mechanism and Eley-Rideal (ER) mechanism were established to correlate the kinetic data. The results indicated that the heterogeneous models exhibited a more satisfactory agreement with the experimental data than the PH model. According to the kinetic studies and spectroscopic analysis, it is proposed that cyclohexene hydration catalyzed by H-ZSM-5 belongs to the ER mechanism, which accounts that the reaction is between adsorbed water and bulk cyclohexene, while it belongs to the LHHW mechanism over the ion-exchange resin. Nevertheless, the activation energies are similar for the two catalysts, which implies similar controlling steps are encountered in the reaction.