alkenestopropeneandethene英文文献.pdf

Applied Catalysis A: General 288 (2005) 134–142 /locate/apcata Catalytic cracking of C4 alkenes to propene and ethene: Influences of zeolites pore structures and Si/Al2 ratios a,b a a a,* Xiangxue Zhu , Shenglin Liu , Yueqin Song , Longya Xu a State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, P.O. Box 110, Dalian 116023, PR China b Graduate School of Chinese Academy of Sciences, Beijing 100039, PR China Received 4 December 2004; received in revised form 9 April 2005; accepted 20 April 2005 Available online 1 June 2005 Abstract Catalytic cracking of butene to propene and ethene was carried out in a continuous plug-flow stainless steel reactor over various zeolites with different pore structures and Si/Al2 ratios. It was found that the porous structure and acidity of zeolites play important roles in the zeolite performance in the butene cracking process. The smaller the pore size of the zeolite catalysts, the higher the initial selectivities towards propene and ethene and the lower the initial selectivities to C3–C4 alkanes. This is attributed to a suppression of the hydrogen transfer reaction of the alkenes. Although high initial selectivities to propene and ethene could be gained on medium-pore zeolites of ZSM-22, ZSM-23, ZSM- 35 and on small-pore zeolite SAPO-34, the stabilities of all these zeolites