【Abstract】 Supported rare earth catalysts were made from Nd(O i Pr) 3 and the chlorides as well as bromides of the elements of ⅠA and ⅡA groups which were used as supporters of the catalyst. In the study on the relationship between the composition of supporters and the polymerization activity of butadiene in the presence of the supported rare earth catalysts, it was found that the electronegativity of ⅠA or ⅡA elements has an obvious effect on the activity of supported catalysts, that is the activity of the supported catalyst increases with the increasing of the electronegativity. This phenomenon is explained in terms of the interaction between the HOMO of the butadiene and the LUMO of the neodymium. This rule also holds in the case when halides of magnesium were used as supporters.更多还原