Ni/γ-Al_2O_3催化剂上丙烯与Ni离子的相互作用

THE INTERACTION OF NICKEL IONS WITH PROPYLENE MOLECULES ON Ni/γ-Al_2O_3 CATALYST

采用ESR和XPS方法考察了丙烯在Ni/γAl2 O3催化剂上的吸附齐聚反应 ,发现反应的诱导期随着反应温度的升高而缩短 .ESR和XPS跟踪考察的结果显示出丙烯与Ni2 +发生强的相互作用 ,首先Ni2 +被丙烯还原为Ni+,然后丙烯再与Ni+配位 ,形成 [Ni(C3H6 ) 2 ]+配位离子 ,该配位离子的形成导致了反应诱导期的消失 .在Ni/γAl2 O3催化的丙烯齐聚反应中 ,催化剂的催化活性中心是Ni+,[Ni(C3H6 ) 2 ]+是反应的前期物种 .

The oligomerization of propylene over Ni/ γ Al 2O 3 catalyst has been investigated with ESR and XPS, in a closed recirculation apparatus. It is found that the induction period of propylene oligome\|rization decreased with the increasing of reaction temperature. The results of ESR and XPS measurements show that the interaction of propylene molecules and nickel ions on Ni/ γ Al 2O 3 catalyst is strong, and the Ni 2+ ions are reduced by propylene to Ni + ions first, then, the Ni + ions form unsatura\|ted complexes [Ni(C 3H 6) 2] +. The induction period of this reaction does not eliminate until the formation of the complexes. In the oligomerization of propylene, the catalytically active centers are Ni + ions and the complexes [Ni(C 3H 6) 2] + are the pre\|species of the propylene oligomerization.