Synthesis and characterization of HZSM-5 zeolite and its catalytic application in the conversion of CH3Br into aromatics

• 1、College of Chemistry and Chemical Engineering, Hunan University

Abstract：This paper describes the synthesis, characterization and catalytic application of H-ZSM-5 zeolites. The H-ZMS-5 was prepared by hydrothermal crystallization method, using n-butylamine (BTA) as template. The as-prepared materials were evaluated for the conversion of CH3Br into aromatics in a fixed-bed reactor. The effects of batch SiO2/Al2O3 ratio, alkalinity, NaCl/Al2O3 ratio, seed crystals and crystallization time on the yield, structure/texture, and catalytic performance of ZSM-5 zeolites were systematically studied. Using the optimum sol (SiO2/Al2O3=70, BTA/SiO2=0.2847, Na2O/SiO2=0.1237, H2O/SiO2=37.4, NaCl/Al2O3=60, and Seed crystals/SiO2=5wt.%), and the preferable crystallization conditions of 100oC/24h-170oC/24h, HZSM-5 zeolites with high crystallinity and a small size of 0.3-0.8 μm were obtained and found to exhibit good activity, selectivity and stability towards the CH3Br conversion into aromatics. The structure-catalytic efficiency relationships of the catalysts were also clarified by the characterization techniques of XRD, SEM, and NH3-TPD. It can be deduced that higher crystallinity or smaller crystal size will favor the improvement of the catalytic activity, selectivity and stability of HZSM-5. Moreover, efficient conversion of methyl bromide into aromatics can be obtained only when the surface acidity of the HZSM-5 zeolite is moderate.

Keywords： ZSM-5 zeolite methyl bromide aromatic hydrocarbon.