大分子正十六烷的催化裂化

以具有新型多级孔中空薄壳结构的ZSM-5分子筛（Gel-ZSM-5）作为催化剂，正十六烷作为探针分子，研究了催化剂的孔道结构及酸性对大分子催化裂化反应的影响.实验结果表明，该催化剂中的介孔、大孔多级结构非常有利于大分子反应物、中间产物以及结焦物在其表面及内部的快速传输，从而大幅提高催化转化率并延长了催化剂寿命；另外，催化剂多级孔表面的大量酸性位点可以显著提高针对大分子的催化反应性能，并且明显改善了产物的选择性.在较短的反应时间下，这种构效关系体现得更加显著.因此，合理的酸性分布和多级中空薄壳孔道结构将赋予催化剂在大分子催化裂化中具有更好的催化活性、选择性及更长的催化寿命，为设计新型高效催化剂提供了依据.

Catalytic Cracking of n-Hexadecane

A new kind of hierarchical ZSM-5 zeolite catalyst with hollow and thin shell structure was synthesized and tested by cracking of n-hexadecane to study its pore effect and acid properties.The results showed that this zeolite catalyst had better catalysis activity and prolonged life because of its improved molecular diffusion brought by its mesopores and macropores.In addition, large amount of acid sites on the hierarchical pores can be more beneficial to large molecular reactions and get better product selectivity.This structure-activity relationship is more obvious especially on short contact time conditions.In a word, catalysts with proper activity distribution as well as hierarchical pores, hollow and thin shell structure should have better activity, product selectivity and prolonged life, which can provide the basis to design novel high-performance catalysts in the future.