Catalytic Property of SAPO-18/SAPO-34 Intergrown Molecular Sieve in 1-Butene Cracking

摘要

SAPO-18 (AEI)/SAPO-34 (CHA) intergrown molecular sieve (AC-HS) was prepared by hydrothermal synthesis. As evidenced by XRD, SEM, BET, and NH3-TPD analyses, AC-HS had unconventional physical and chemical properties such as crystal structure, crystal morphology, surface area, and acidity. Compared with SAPO-18 and SAPO-34 mechanical mixture (AC-MM), AC-HS showed better initial activity and higher selectivities of C3H6 and C2H4 + C3H6 in 1-butene cracking under the reaction conditions. The selectivities of C3H6 and C2H4+C3H6 reached approximately 61.09% and 90.28%, respectively, when conversion was >70%. Regarding the SAPO-18/SAPO-34 intergrown molecular sieve, the relationship of acidity and catalytic performance was not close in 1-butene cracking, and the intergrowth structure should play a significant important role in the selectivity of olefins.