Catalytic cracking of 1-butene to propene and ethene on MCM-22 zeolite

Catalytic cracking of butene to propene and ethene was investigated over HMCM-22 zeolite. The performance of HMCM-22 zeolite was markedly influenced by time-on-stream (TOS) and reaction conditions. A rapid deactivation during the first 1 h reaction, followed by a quasi-plateau in activity, was observed in the process along with significant changes in product distributions, which can be attributed to the fast coking process occurring in the large supercages of MCM-22. Properly selected reaction conditions can suppress the secondary reactions and enhance the production of propene and ethene. According to the product distribution under different butene conversion, we propose a simple reaction pathway for forming the propene, ethene and by-products from butene cracking. HMCM-22 exhibited similar product distribution with the mostly used high silica ZSM-5 zeolite under the same conversion levels. High selectivities of propene and ethene were obtained, indicating that the 10-member ring of MCM-22 zeolite played the dominant role after 1 h of TOS. However, MCM-22 exhibited lower activity and stability than that on high silica ZSM-5 zeolite with longer time-on-stream.