Direct synthesis of cyclopentadiene from n-pentane through dehydrocyclization over Pt loaded on Zn-containing zeolite

The interaction between Pt and Zn caused by loading Pt on Zn sites incorporated in zeolite has been focused on for enhancing the catalytic properties in the dehydrogenation of light alkanes. In this study, Pt loaded on Zn-containing zeolite catalysts were developed and applied to the dehydrocyclization of n -pentane. Among the zeolite catalysts, Pt loaded on Zn-containing MFI zeolite (Pt/Zn-MFI), whose zeolite was synthesized through the pre-heating of a silica source in a basic medium and followed by the hydrothermal treatment, exhibited remarkably high catalytic performances for the dehydrocyclization of n -pentane to mainly produce cyclopentadiene (CPD). Silica sources used in the synthesis of Zn-MFI influenced the catalytic properties; silica sources containing no other element such as tetraethyl orthosilicate, fumed silica, and Silicalite-1 were effective in promoting the catalytic activity for the dehydrocyclization. In addition, small-sized Pt complex as a Pt source was also effective in enhancing the productivity of CPD because Pt species were accessible to Zn sites in the zeolite for the interaction between Pt and Zn. The Zn sites in the zeolite were specifically active for the dehydrocyclization of n -pentane even with no Pt species, while no enhancement of the catalytic activity was observed over the physical mixture of Zn-MFI and Pt loaded on Silicalite-1. Furthermore, the increase in the Zn and Pt contents improved the catalytic activity, suggesting that anchoring Pt on Zn sites in the zeolite played an important role in improving the catalytic performances for the dehydrocyclization of n -pentane to CPD. • Pt/Zn-MFI exhibited high catalytic performances for the dehydrocyclization of n -pentane. • Cyclopentadiene was directly produced through the dehydrocyclization of n -pentane. • SiO 2 sources for the synthesis of zeolite influenced the catalytic performances. • Combination of Zn-MFI and small-sized Pt complex promoted the dehydrocyclization of n -pentane. • Increased Zn and Pt content improved the catalytic performances.