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通过浸渍法制备了Pt/SAPO-11催化剂,分步浸渍法制备了Zn-Pt/SAPO-11双金属催化剂.通过X射线衍射、低温氮物理吸附、氨程序升温脱附和吡啶吸附红外等手段对所得样品进行了表征.实验结果表明,助剂Zn的引入导致了催化剂的比表面积和孔容降低,B酸量减少而L酸量增加,总酸量有所增加.在300～380℃范围内对正庚烷的临氢异构化反应考察发现,引入金属助剂Zn可以明显改变正庚烷的转化率,而对C7异构体的选择性影响不明显.当Zn质量分数为0.2%,Pt质量分数为0.2%时,Zn-Pt/SAPO-11催化剂的正庚烷转化率及C7异构体收率达到最大值;Zn含量继续增加时,正庚烷转化率及C7异构体收率均随之下降.实验结果表明,双功能催化剂中金属功能与酸性功能的匹配对正庚烷临氢异构化反应非常重要.
Pt / SAPO-11 catalyst was prepared by impregnation method and Zn-Pt / SAPO-11 bimetallic catalyst was prepared by step impregnation method. The effects of XRD, physical adsorption of low temperature nitrogen, temperature programmed desorption by ammonia and pyridine adsorption on The results showed that the addition of Zn led to the reduction of specific surface area and pore volume of catalyst, the decrease of B acid amount and the increase of L acid amount and the increase of total acid amount.In the range of 300 ~ 380 ℃ Hydrogen isomerization of n-heptane was found that the introduction of metal additives Zn can significantly change the conversion of n-heptane, but the selectivity of C7 isomers is not obvious.When the mass fraction of Zn is 0.2% When the mass fraction of Pt was 0.2%, the conversion of n-heptane and the yield of C7 isomers reached the maximum value for Zn-Pt / SAPO-11 catalyst. When the content of Zn increased, the conversion of n-heptane and the yield of C7 isomer The experimental results show that the matching of metal functions and acid functions in bifunctional catalysts is very important for the hydroisomerization reaction of n-heptane.