In order to crack hydrocarbons with a large molecular weight, it is necessary to diffuse those substrates deeply into the inside of a catalyst. Catalysts having the hierarchical structure including not only micropores of zeolites in the inner side but also large mesopores in the outer side could crack large molecules of hydrocarbons quite effectively. To prepare such hierarchical catalysts, in this study, ZSM-5, Y and β zeolites were uniformly dispersed in silicas with large mesopores generated by the gel skeletal reinforcement (GSR) method. It was observed by XRD measurement that these catalysts maintained the framework of zeolite. Nitrogen adsorption and desorption measurement exhibited that the maximum pore volume and pore diameter of catalysts reached 5 cm³/g and 50 nm, respectively. These results indicated that silica having large mesopores would be present around the zeolite. When catalytic cracking of n-dodecane using these catalysts was performed, the ZSM-5-containing hierarchical catalysts exhibited 30% higher conversions than that of zeolite single. When catalysts containing β- and Y-zeolites were used, the ratios of multi-branched hydrocarbons/single-branched hydrocarbons (m/s) and olefin/paraffin (O/P) ratios in the gasoline fraction were about 1.5–2 times higher than those of ZSM-5-containing catalysts. The O/P ratios and conversions increased as the mesoporous diameter increased while the iso-/n- ratio of the gasoline fraction tended to depend on the microporous sizes of the zeolites.

为了裂解大分子量的碳氢化合物，需要将这些底物深入扩散到催化剂内部。具有分级结构的催化剂不仅包括内侧的沸石微孔，而且包括外侧的大中孔，可以非常有效地裂解大分子烃。为了制备这种分级催化剂，在本研究中，ZSM-5、Y 和 β 沸石均匀分散在通过凝胶骨架增强（GSR）方法产生的具有大中孔的二氧化硅中。通过XRD测量观察到这些催化剂保持了沸石的骨架。氮吸附和解吸测量表明催化剂的最大孔体积和孔径达到5 cm ³/g 和 50 nm，分别。这些结果表明沸石周围将存在具有大中孔的二氧化硅。当使用这些催化剂进行正十二烷的催化裂化时，含有 ZSM-5 的分级催化剂的转化率比单一沸石的转化率高 30%。当使用含有 β- 和 Y-沸石的催化剂时，汽油馏分中多支链烃/单支链烃的比率 (m/s) 和烯烃/链烷烃 (O/P) 的比率高出约 1.5-2 倍比那些含有 ZSM-5 的催化剂。O/P 比和转化率随着中孔直径的增加而增加，而汽油馏分的iso- / n-比倾向于取决于沸石的微孔尺寸。