【摘要】 采用正丁胺化学吸附和程序升温脱附(TPD)的方法,探讨了丝光沸石(Ⅰ)的残钠量、硅铝比对催化剂表面酸性质的影响,并和催化剂上正己烷异构化反应活性作了关联。还结合用吡啶作探针分子的FT-红外光谱分析,探讨了Ⅰ中引入第Ⅷ族过渡金属元素后对催化剂表面酸性质的影响。结果表明:Ⅰ上的表面酸中心区分为两类:一类是酸强度较弱(TPD谱峰顶温T_M<350℃)的低温酸性中心;另一类是酸强度较大(T_M>350℃)的高温酸性中心。对正己烷异构化反应主要是后者起催化作用。在较低的硅铝比下,Ⅰ经部分脱铝,有助于提高催化剂表面的酸强度和酸浓度。第Ⅷ族过渡金属元索引入Ⅰ中,将优先定位于强的B酸中心附近,并明显改变了Ⅰ的表面酸中心分布,使之有利于异构化反应。更多还原

【Abstract】 By TPD Technique with n-butylamine, the effects offered by the residual sodium and SiO₂/Al₂O₃ ratio of mordenite on the acid behavior at the surface of catalyst have been investigated, and the results obtained thereby have been correlated with the activity of the catalyst on the proceeding of isomerization of n-hexane. Furthermore, the behavior of the modified surface by introducing in Group Ⅷ elements as well as the FT-IR spectra were studied, in which the adsorbed pyridine was used as a molecular probe.What the experimental results revealed are:1. The acidic centre at the surface of catalyst may be divided into a low temperature, （T_M<350℃）, site of low strength and a higher temperature, （T_M>350℃）, one of stronger strength, and the latter must be responsible for the strengthening the activity of isomerization of n-hexane;2. The low SiO₂/Al₂O₃ ratio and the partial dealuminium of mordenite will both enhance the acidic intensity and concentration;3. The Group Ⅷ elements introduced in the mordenite would take its proper position earlier at the vicinity of the region of strong Br（?）nsted acidic sites, and change the site location conspicuously, thus the proceeding of isomerization is favored.更多还原