Synthesis And Aftertreatment Of Hierarchical ZSM-5and Its Application In MTA

ZSM-5has been widely used in petrochemical and fine chemical catalysis for it’s three-dimensional pores with uniform size, excellent shape selective catalysis and favourable hydrothermal stability. However, the microporous of ZSM-5has limited the diffusion of large molecules during catalytic reactions, thereby affecting the activity and life span of catalyst. A right way to solve the problem of diffusion limitation is to introduce mesoporous into microporous zeolites.In this paper, mesoporous ZSM-5had been synthesized by hydrothermal crystallization method, with TPAOH as template, CTAB as mesoporous structure directing agent. The effects of different synthesis conditions were investigated on hierarchical ZSM-5, and characterization methods such as XRD, FT-IR, SEM, N2adsorption-desorption and NH3-TPD were used to study the structure and physicochemical properties of hierarchical ZSM-5. In order to increace mesoporous, hierarchical ZSM-5synthetized was further aftertreated. The catalytic performances of hierarchical ZSM-5in MTA were also investigated. Compared to traditional ZSM-5zeolite, hierarchical ZSM-5synthetized showed higher aromatics yield and selectivity of BTX in MTA. Moreover, the aftertreatment of hierarchical ZSM-5further improved its aromatics yield.