不同分子筛负载Pt催化剂上的正己烷异构化

 以不同分子筛为载体通过浸渍法制备了一系列Pt/分子筛催化剂，考察了正己烷在不同催化剂上的临氢异构化反应性能，同时也考察了分子筛的孔道结构对催化剂积碳性能的影响。分子筛的酸性和反应后催化剂上的积碳量分别通过NH3-TPD和TGA表征。结果表明，催化剂的异构化性能同时受分子筛的孔道结构和酸性的影响。具有一定量强酸中心、合适孔道结构的分子筛负载Pt的催化剂有利于提高正己烷异构化活性，正己烷异构化选择性依赖于分子筛的孔道结构，而酸性对异构选择性无直接影响。分子筛上的强酸中心越多，孔径越大，越有利于多甲基异构体的生成。此外，催化剂的抗积碳性能与分子筛的孔道结构有关。

ISOMERIZATION PERFORMANCES OF N-HEXANE OVER DIFFERENT ZEOLITES SUPPORTED PT CATALYSTS

Different zeolites supported Pt catalysts were prepared by impregnation method. The acidity of different zeolites and coke amount on spent catalysts were characterized by NH3-TPD and TGA, respectively. The effects of the acidity and pore channel structure of zeolite on hydro-isomerization performances of n-hexane over different Pt/zeolite catalysts were investigated. The results indicated that the zeolite-supported Pt catalyst in which the zeolites had large amount of strong acid sites and relatively large size of pore channel possessed the high isomerizing activity. The selectivity of i-hexane was strongly dependent on the pore structure of zeolite and irrespective of zeolite acidity. Moreover, the formation of the bulky isomers (DMB) was more favorable on Pt supported on zeolite possessing the large size of pore channel and large amount of strong acid sites. The resistance to coking of catalyst was also related to the pore geometry of zeolite.