ZSM-5-SBA-15复合分子筛制备及甲苯甲醇烷基化性能研究

Preparation of ZSM-5-SBA-15 composite molecular sieves and its performance for toluene alkylation with methanol

摘要: 采用后合成法制备了ZSM-5-SBA-15复合分子筛,通过XRD、FT-IR、BET、NH₃-TPD及吡啶红外等手段表征催化剂的性质。结果表明,ZSM-5-SBA-15既具有微孔结构又具有介孔结构。吡啶吸附和NH₃吸脱附实验结果表明,ZSM-5微孔分子筛的引入使SBA-15介孔分子筛的酸性增强,但与ZSM-5相比,ZSM-5-SBA-15复合分子筛的酸性位没有改变,酸强度有一定的减弱。用固定床评价了该复合分子筛甲苯甲醇烷基化反应的催化性能。结果表明,与常规ZSM-5相比,ZSM-5-SBA-15表现出了较高的对位选择性。

Abstract: A series of ZSM-5-SBA-15 composite molecular sieves were prepared by post-synthesis method and characterized by XRD, FT-IR, BET, NH₃-TPD and pyridine infrared. The results indicated that ZSM-5-SBA-15 has both ZSM-5 microporous and SBA-15 mesoporous structure. The adsorption-desorption measurement using pyridine and ammonia demonstrated that acidity of SBA-15 was heightened because ZSM-5 was introduced into. Compared with ZSM-5, the acidic sites on ZSM-5-SBA-15 were still accessible. However, the strength of acidity was weakened. In the probe reaction of the alkylation of toluene and methanol, the ZSM-5-SBA-15 composite exhibited higher para-xylene selectivity in comparison to pristine ZSM-5.