NiSO_4/HY中镍含量对异丁烯齐聚反应的影响

用浸渍法制备了一系列Ni含量不同的NiSO_4/HY催化剂,在常压,180℃和GHSV为180h~(-1)的条件下进行了异丁烯气相齐聚反应。实验发现:当催化剂中镍的含量低于6％(w)时,异丁烯的齐聚反应显示出较高的活性和较好的二聚选择性。X光衍射结果证明:当镍的含量增加到6％(w)以上时,XRD谱图中出现了明显的NiSO_4晶体特征衍射峰,而当低于此值时,NiSO_4在HY分子筛表面以单层分散的状态存在,NH_3-TPD和TPR的结果表明:在HY中引入NiSO_4并没有引起催化剂酸性的明显改变,HY起着分散活性组分的作用。

EFFECTS OF Ni CONTENT IN NiSO_4/HY ON ISOBUTENE OLIGOMERIZATION

NiSO4/HY catalysts with different Ni contents were prepared by impregnation method. Oligomerization of isobutene was carried out at 180C, atmospheric pressure and 180h-1 GHSV. It was found that higher activity and better dimerization selectivity was observed when Ni content in catalysts was less than 6%. XRD results showed that NiSO4 was dispersed in monolayer form for the catalysts mentioned above. On the contrary,characteristic peaks due to NiSO4 crystallites appeared while Ni content was more than 6%. Results of NH3-TPD and TPR revealed that the incorporation of NiSO4 into HY did not change the catalyst acidity remarkable. HY played a role accouting for the dispersion of NiSO4 over HY.