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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。
The Hβ zeolites modified with rare earth (La, Ce, Nd) and Hβ zeolites were studied by infrared spectroscopy (IR). The infrared spectra of Hβ zeolites and La-Hβ zeolites after the alkylation of benzene- spectrum. The changes of the intensity of 1545cm -1 (Bronsted acid) and 1454cm -1 (Lewis acid) absorption peak at different temperatures after adsorption of pyridine were investigated. It is found that there are two peaks at 3615 cm -1 and 3740 cm -1 wavenumbers which show the vibration of OH groups. The former is corresponding to Bronsted acid and the latter is more acidic. Rare earth oxide modification decreased the amount of B acid and increased the amount of L acid, and two new absorption peaks appeared at the wave numbers of 1603 cm -1 and 1445 cm -1. In this paper, the relationship between the activity and the stability of benzene-isopropanol alkylation reaction and the surface acidity of zeolite was discussed.