关键词: ZSM-11分子筛, 碱处理, 多级孔, 间二甲苯, 异构化, 对二甲苯, 邻二甲苯

Abstract: ZSM-11 zeolite was synthesized by dynamic crystallization method and treated with different intensity of alkali to obtain the modified samples. The physical and chemical properties of the samples before and after alkali treatment were characterized and compared by using XRD,N₂ adsorption-desorption,XRF,NMR,SEM,NH₃-TPD and Py-FTIR. The results showed that part of the skeleton siliconation of the ZSM-11 zeolite could be removed by alkali modification, changing the crystal morphology and crystallinity of samples, and a certain amount of mesoporous was introduced, forming a more interconnected hierarchical pore structure,which increased the specific surface area. Alkali treatment also could modulate the acid amount of ZSM-11 with more exposed acid sites which significantly enhance isomerization activity. The catalytic performances of the samples were evaluated by using m-xylene isomerization. The results showed that ZSM-11 treated with 0.5 mol/L NaOH solution exhibited the best enhancement in m-xylene isomerization activity.

Key words: ZSM-11 zeolite, alkali treatment, hierarchical pore, m-xylene, isomerization, p-xylene, o-xylene