摘要
ＨＺＳＭ－２０沸石分子筛的水蒸汽改性项寿鹤，任大立，王敬中，李赫晅（南开大学化学系，天津３０００７１）关键词ＨＺＳＭ－２０沸石，水蒸汽处理，改性ＺＳＭ－２０沸石是一种具有大孔和开放结构的分子筛［１］，其结构与八面沸石（如Ｙ型沸石）类似，但其硅铝比较高...
he influence of steanl treatment on the structure and properties of HZSM-20 was investigated. HZSM-20 was easily modified by steam treatment. The band of Si (2Al) in the 29Si NMR spectrum disappeared when HZSM-20 was steamed at 400℃ for 2 h. The framework St/AI ra-no was increased from 4.3 to 27 as steaming at 50℃ for 2 h. During steaming0 first the crystallinity of HZSM-20 decreased, then it came up,finally it overrode the crystallinity of original HZSM-20, and the relative intensities of XRD of various crystal planes also varied. The steam treatment lead to reordering and recrystallization of the structure of HZSM-20.The degree,of dealumillation was increased with increasing the time and the temperature of steam treatment, while the amount of the Brdnsted acid sites was decreased, and the cracking activity for hexane came down. The deep dealumination would lead to weaking obviously the intensity of acidity of HZSM-20.
基金
国家自然科学基金
