Physical and chemical properties of micro-mesoporous catalysts with tetrapropylammonium hydroxide treatment and their performance in thiophene alkylation

HZSM-5 zeolites with different molar ratios of SiO₂/Al₂O₃ were treated by different concentrations of tetrapropylammonium hydroxide (TPAOH) solution. HZSM-5 zeolites with micro-meso pores were synthesized. The results show that the treatment of HZSM-5 zeolite with different molar ratios of SiO₂/Al₂O₃ by different concentrations of TPAOH could cause desilication. The pore diameter of mesopores increases with the increase of TPAOH concentration and SiO₂/Al₂O₃ molar ratios. Meanwhile, the acidic properties were adjusted. HZSM-5 zeolites were treated by different concentrations of TPAOH solution, whose SiO₂/Al₂O₃ molar ratios are 50, 80 and 150. HZSM-5 with SiO₂/Al₂O₃ molar ratio of 50 is obviously better than others in the content of relative acid, L-acid, B-acid and the strength of weak acid. HZSM-5 (SiO₂/Al₂O₃ molar ratios is 50) by the treatment of TPAOH in different contents is most preferable for thiophene alkylation.