摘要
在反应条件下付里叶变换红外光谱技术的研究，揭示了高晶格铝含量（每结构单元含７．６８个铝）的沸石ＺＳＭ－５有新类型的Ｂ酸．基于甲醇和甲醇脱水物二甲基醚与Ｂ酸的相互作用，在红外差谱中，原来表征Ｂ酸在ＯＨ伸缩频率区的特征吸收谱带３６１０ｃｍ－１不再出现，代之以两个负吸收谱带，分别为３６１５与３５８５ｃｍ－１，这是以往的研究中未报导过的红外吸收谱带．
In this study, by using in situ FTIR technique, a novel type of Brnsted acid sites on ZSM 5 zeolite with high framework aluminum (7.68 Al per unit cell) had been revealed. After methanol and dimethylether adsorption onto a freshly activated ZSM 5 sample with Si/Al ratio of 12, the infrared absorption band at 3610 cm -1 , assigned to the OH stretching vibration frequency of the Bronsted acid site in ZSM 5, disappeared concomitantly with the appearance of two negative infrared absorption bands at 3615 and 3585 cm -1 . This observation of the presence of a second type of Brnsted acid sites supports Haw′s similar finding obtained in ZSM 5 zeolite by 1H MAS NMR spectroscopy.
出处
《分子催化》
EI
CAS
CSCD
1996年第3期183-186,共4页
Journal of Molecular Catalysis(China)
