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本文考察了SO_4~(2-)ZrO_2固体超强酸催化剂上正构烷烃的反应及影响催化剂活性和选择性的各种因素.结果表明:烷烃的骨架异构化和裂解反应在催化剂上同时进行,烷烃的碳原子数增加,催化剂活性提高,裂解反应比例增加,降低反应温度有利于骨架异构化反应;同时催化剂的反应性能与含水量关系十分密切,完全脱水的催化剂活性很低,少量水的存在有利于提高催化活性,过量的水又可使催化剂失活.根据催化剂的热重分析、红外光谱和反应数据,提出低温时正戊烷反应主要在催化剂表面B酸位上进行,随着反应温度升高和烷烃碳原子数增加,催化剂表面的L酸位才显示一定的活性.
In this paper, the reaction of n-alkanes on SO_4 ~ (2-) ZrO_2 solid superacid catalyst and the various factors affecting the activity and selectivity of the catalysts were investigated.The results showed that the isomerization and cleavage of alkanes were carried out simultaneously on the catalysts, The carbon number of alkane increased, the activity of catalyst increased, the proportion of pyrolysis reaction increased, and the reaction temperature decreased, which was in favor of the isomerization reaction. At the same time, the reactivity of catalyst was closely related to the water content. The activity of completely dehydrated catalyst was very low. The existence of is conducive to improve the catalytic activity, excess water can deactivate the catalyst.According to the thermogravimetric analysis of the catalyst, infrared spectra and reaction data, it is proposed that the n-pentane reaction is mainly carried out on the catalyst surface B acid sites at low temperature, When the temperature is increased and the number of carbon atoms of the alkane is increased, the L acid sites on the catalyst surface show some activity.