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用TPD、IR和BET方法研究了β沸石的表面酸性质和测定了对苯、乙苯、环己烷和邻二甲苯的吸附等温线,并且以苯和乙醇烷基化合成乙苯作为指标反应考察了β沸石的催化性能。实验结果表明,在TPD谱图上出现两个NH_3的脱附峰,T_M值分别为220～240℃和360～400℃。IR分析证明β沸石表面存在L酸和B酸中心.P改性使β沸石总酸量下降,孔径变小,从而提高了β沸石催化剂对苯和乙醇烷基化合成乙苯反应的选择性,催化剂表面结炭量减小。催化剂表面结炭量随总酸量的增加而增大。β沸石对苯、乙苯、环已烷和邻二甲苯的吸附等温线均属1型等温线。吸附量比HZSM-5大.P改性后吸附量下降。β沸石的孔径大于6.6A.
The surface acidity of β zeolite was studied by TPD, IR and BET methods. The adsorption isotherms of benzene, ethylbenzene, cyclohexane and o-xylene were determined, and ethylbenzene was synthesized by the alkylation of benzene with ethanol. The catalytic performance of zeolite beta was investigated. The experimental results show that two NH 3 desorption peaks appear on the TPD spectrum with T_M values of 220-240 ℃ and 360-400 ℃, respectively. IR analysis showed that the presence of L acid and B acid center on the surface of β zeolite.P modification reduced the total acidity of β zeolite and decreased the pore size and thus enhanced the selectivity of β zeolite to alkylation of benzene and ethanol to ethylbenzene, The amount of carbon on the catalyst surface decreases. The amount of carbon on the catalyst surface increases with the increase of total acidity. The adsorption isotherms of β zeolite for benzene, ethylbenzene, cyclohexane and o-xylene belong to type 1 isotherm. The adsorption capacity is larger than that of HZSM-5, and the adsorption capacity of P after modification decreases. Beta zeolite pore size greater than 6.6A.