摘要
Developing efficient and stable zeolites for vapor-phase Beckmann rearrangement of cyclohexanone oxime is still a great challenge to realizeε-caprolactam(CPL)green production.In this work,the hierarchical porous silicalite-1 zeolites with multiple hollow structure(S-1-M)are explored by in-situ desilication−recrystallization post-treatment of spongy highway-like zeolites(S-1-S),which are synthesized through silanization synthesis of conventional bulky silicalite-1(S-1).Compared to S-1,S-1-M achieves superior catalytic performance,with improving the CPL selectivity from 85.7%to 94.1%and prolonging the catalyst lifetime from 74 to 126 h at a weight hourly space velocity(WHSV)of 6 h^(−1).Comprehensive physiochemical studies demonstrate that the highly dispersed intracrystalline cavities within S-1-M endow greater mass diffusion and better quasi acidity inducing by the enhanced H-bonds among abundant H-bonded silanols,which is cooperatively responsible for its superior catalytic performance.
基金
the National Key Basic Research Development Plan“973”Project(No.2006CB202508)
the National Key R&D Program of China(No.2021YFA1502600)
State Key Laboratory of Catalytic Materials and Reaction Engineering(RIPP,SINOPEC)(No.33600000-20-ZC0607-0024)
the SINOPEC Project(Nos.411058 and 413025)
the National Natural Science Foundation(Nos.21808244,22178347,and 22072182).
