PDDA辅助模板合成多级孔ZSM-5分子筛及其催化裂解性能

Synthesis of hierarchical ZSM-5 zeolite with PDDA as assistant template and its catalytic cracking performance

以硅溶胶为硅源,四丙基溴化铵为主模板剂,聚二甲基二烯丙基氯化铵(PDDA)为辅助模板剂水热合成了多级孔HZSM-5分子筛,调查了PDDA分子量和添加量对分子筛结构和催化性能的影响。结果表明:随着PDDA的加入,分子筛的孔径由3.78 nm增加至5.15 nm,强酸占比由26.2%增加至41.7%,相比于分子量,PDDA添加量对分子筛孔结构和酸性的影响更为显著。HDPE塑料催化裂解研究表明,合成的分子筛获得了较高的液体产率(30.1%)和轻质芳烃选选择性(73.5%),展示了较好的催化能力和抗积碳性能,实验结果为废塑料的资源化和探索芳烃生产的新途径奠定了理论基础。

Hierarchical HZSM-5 zeolite was hydrothermally synthesized by colloidal silica as silicon resource,tetrapropylammonium bromide as main template,and polydimethyl diallyl ammonium chloride(PDDA)as assistant template.The influence of the molecular weight and addition amount of PDDA on the structure and catalytic performance of the zeolites was investigated.The results show that with the introduction of PDDA,the pore size of the zeolites increased from 3.78 nm to 5.15 nm,the proportion of strong acid sites increased from 26.2%to 41.7%,and the effect of addition amount of PDDA on pore structure and acidity of zeolites was more pronounced.The results from catalytic cracking of HDPE show that the obtained hierarchical zeolite achieved a high liquid yield(30.1%)and the selectivity to monocyclic aromatics(73.5%),and exhibited good catalytic ability and carbon deposition resistance.The results lay the theoretic foundation for recycling of plastic wastes and developing new approaches for production of aromatics.