Hβ沸石及其稀土改性后红外光谱研究  

IR STUDIES OF H-BETA AND RARE-EARTH MODIFIED H-BETA ZEOLITES

作　　者：贾春娟[1] 潘履让[1] 李赫咺[1] 

机构地区：[1]南开大学化学系,天津300071

出　　处：《燃料化学学报》1992年第4期350-354,共5页Journal of Fuel Chemistry and Technology

基　　金：国家自然科学基金

摘　　要：用红外光谱(IR)研究了Hβ沸石和稀土(La、Ce、Nd)氧化物改性的Hβ沸石,同时测定了苯-异丙醇烷基化反应后的Hβ沸石和La-Hβ沸石的红外光谱。考察了吸附吡啶后不同温度脱附时1545cm^(-1)吸收峰(Bronsted酸)和1454cm^(-1)吸收峰(Lewis酸)强度的变化。实验发现,在波数为3615cm^(-1)和3740cm^(-1)处有两个表示OH基振动的谱峰,前者与Bronsted酸相对应,酸性较强。稀土氧化物改性降低了B酸量,增加了L酸量,而且在波数为1603cm^(-1)和1445cm^(-1)处出现两个新的吸收峰。本文讨论了苯-异丙醇烷基化反应活性、稳定性与沸石表面酸性质的关系。H-BETA zeolite and samples modified with oxides of La,Ce, and Nd were studied by means of infrared spectroscopy. H-Beta and La-Hβ samples after use for the alkylation of benzene with isopropanol were also examined by IR. The intensity of spectral bands around 1545cm^(-1) (Bronsted acid) and 1454cm^(-1) (Lewis acid) and their changes with diff erent temperatures of pyridine desorption were examined for characterizing the quantity and strength of surface acidic sites of the zeolites. Two types of acidic OH groups with bands at 3615cm^(-1) and 3740cm^(-1) were foun(?) in the region for OH stretching vibration. The acid strength was stronger for the former, corresponding to Bronsted acid sites (1545cm^(-1)). Modi(?)ication of H-Beta zeolite with rare-earth oxides decreased the quantity of Bronsted acid and two new bands appeared at 1603cm^(-1) and 1445cm^(-1), while the quantity of Lewis acid increased.The relationship between the catalytic activity and stability of the zeolites for the alkylation of benzene with isopropanol, and their surface acidity has been discussed.

关 键 词：稀土元素 改性 红外光谱学 分子筛 

分 类 号：TQ424.25[化学工程]