The Tetralin Hydrocracking Process on Pt/Zeolite Catalysts
1. Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China;
2. University of Chinese Academy of Sciences, Beijing 100049, China;
3. State Key Laboratory of Green Chemical Engineering and Industrial Catalysis, Shanghai Research Institute of Petrochemical Technology, SINOPEC, Shanghai 201208, China
Abstract Tetralin is an important product or intermediate during polycyclic aromatic hydrocarbons (PAHs) hydroconversion, and the study of its hydrocracking behavior is of great significance in the field of heavy aromatics conversion and removal. Herein, Pt/Al2O3, Ir/Al2O3 and Pd/Al2O3 as well as Pt/MOR and Pt/ZSM-5 catalysts were prepared by volumetric immersion method, and the catalytic performances of tetralin hydrocracking over them was investigated detailedly. The results showed that the alumina supported noble metals catalysts mainly showed hydrogenation and dehydrogenation activity, in which Pt presented the highest catalytic activity of hydrogenation and dehydrogenation. Tetraline underwent complex reactions such as hydrocracking, isomerization, hydrogen transfer and alkylation over the zeolite supported catalysts, and the improved hydrocracking activity and selectivity were achieved over Pt/zeolite catalysts with the enhanced Br?nsted acid activity via the hydrogen spillover of Pt. However, excessive Pt loading would aggravate the hydrogenation of benzene ring, which was not conducive to the formation of monocyclic aromatics. Furthermore, the confinement effect of zeolite channels played an important role in the catalytic activity and product distribution during tetralin conversion. Pt/MOR showed higher cracking activity and isomerization selectivity than that of Pt/ZSM-5. It was deduced that the tetraline conversion into light aromatics was mainly carried out through the isomerization-cracking path, and the isomer configuration determined the distribution of cracking products.
