不同碱处理制备多级孔HZSM-5催化剂及噻吩烷基化性能研究

用Na₂CO₃、TPAOH和TPA⁺/CO₃^2-混合碱分别处理HZSM-5分子筛,采用FT-IR、XRD、XRF、N₂吸附脱附、SEM、NH₃-TPD及Py-FTIR表征手段对各类碱处理前后的HZSM-5分子筛进行表征。结果表明,3种类型的碱处理HZSM-5分子筛后,均能形成微孔-介孔多级孔道的HZSM-5(A)催化剂,并能调变催化剂的酸性,其中,TPA⁺/CO₃^2-混合碱处理得到的HZSM-5(TPA⁺/CO₃^2-)催化剂,比表面积最大,介孔数量最多。在小型固定床反应器上,考察了HZSM-5和HZSM-5(A)催化剂的噻吩烷基化性能,结果表明,HZSM-5(TPA⁺/CO₃^2-)催化剂因为具有适当的多级孔孔道和较多的B酸中心而表现出较高的噻吩转化率和1-己烯对噻吩的选择性。

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.