Study on thiophene alkylation performance of hierarchical ZSM-5 zeolites modified by different alikali

HZSM-5 zeolites were respectively treated by Na₂CO₃,TPAOH and mixed alkali solution of TPA⁺/CO₃^2-. The samples were characterized by FT-IR XRD, XRF, N₂ adsorption/desorption, SEM, NH₃-TPD and Py-FTIR techniques. It was found that the microporous and mesoporous hierarchical HZSM-5 (A) catalysts were formed after the treatment and their acidity were modulated. The largest surface area and the most mesoporous were found in the HZSM-5(TPA⁺/CO₃^2-) treated by the mixed alkali of TPA⁺/CO₃^2- s. The thiophene alkylation performance of HZSM-5 and HZSM-5(A) zeolites was investigated in a small-scale fixed bed reactor with model compounds as feedstock. The co-sequences displayed that HZSM-5 (TPA⁺/CO₃^2-) catalysts exhibited the higher conversion of thiophene and selectivity of 1-hexene because the zeolites had proper hierarchical pore diameter and more B-acid sites.