浸渍次序对双元改性HZSM—5上正戊烷芳构化反应的影响

本文研究了不同浸渍次序对Ｚｎ－Ｍ双元改性ＨＺＳＭ－５催化剂芳构化性能的影响。结果表明，对于Ｚｎ－Ｍ双元改性ＨＺＳＭ－５催化剂来讲，先引入Ｚｎ组分，然后再引入Ｃｕ、Ａｌ等其它组分改性效果最佳，而同时引入两种改性组分的效果最差。这种差异是由于改变浸渍次序而引起的表面活性中心的不同造成的。

The Effect of Impegnation Sequence of Modifiers on the n-Pentane Aromatization over Zn-M-HZSM-5 Catalysts

The effect of impregnation sequence of modifiers on the aromatization reactivity of Zn-M-HZSM-5 Catalysts was studied The results showed that, Zn modified first on HZSM-5 had better activity and aromatics yield than first introducing other modifiers such as Cu, Al; impregnating Zn and other modifiers at the same time on HZSM-5, the aromatization properties of the catalysts were not so good as the first two methods Analyzing the products distribution, we found that the amount of small alkanes such as CH\-4 and C\-2H\-6 was related to the aromatics yield-the more the former, the less the latter-, and small alkanes were produced from acid-catalyzed cracking and hydrid-transfer reactions Combined with the NH\-3-TPD results, it can be concluded that :Zn modified first on HZSM-5 can form a new type of active site on which n-pentane was activated via dehydrogenation pathway, so that the amount of light alkanes was reduced Other modifer introduced first or together with Zn on HZSM-5 will occopy some vantage positions on HZSM-5, and the new active center cannot be properly formed, thus they have less aromatics yields