Selective Synthesis of Methylcyclopentane from Cyclohexane Using Pt-Hybrid Catalyst.

Abstract

Isomerization of cyclohexane to methylcyclopentane was studied on a series of ZSM-5catalyst in the presence of hydrogen. A Pt-ZSM-5 catalyst, which is typical dual functional catalyst for skeletal isomerization, showed high activity and high methylcyclopentane selectivity. A hybrid catalyst prepared by physically mixing H-ZSM-5 and Pt/SiO 2 showed high activity and selectivity equal to those of Pt/ZSM-5 while a H-ZSM-5 and a Pt/SiO 2 showed a poor catalytic performance for this reaction. With the hybrid catalyzed reaction, the mixing state of H-ZSM-5 and Pt/SiO 2 had a strong influence on the activity and methylcyclopentane selectivity. In the absence of hydrogen, the conversion of cyclohexane was drastically reduced and cracking reaction became dominant. These results suggest that spilt-over hydrogen plays an important role in cycloparaffin activation and the stabilization of intermediates to give high isomer yield.