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稀土羧酸盐,如辛酸盐,硬酯酸盐和环烷酸盐等组成的催化体系对共轭双烯烃聚合具有良好的活性和定向效应。但体系中要有第三组分的存在,通常采用的是烷基氯化铝,其作用是与羧酸盐羧基进行交换反应,是形成活性中心的必要条件。氯化稀土组成的体系由于自身组成含有氯离子而排除了第三组分的使用,从而简化了聚合工艺流程,有利于研究体系组分之间的反应。但是并非所有氯化稀土都适宜于这种研究,原因在于大多数氯化稀土络合物不溶于惰性有机溶剂。如氯化稀土醇合物对共轭双烯烃聚合有着相当高的活性,但是研究氯化稀土醇合物与烷基铝的反应却有着一定的困难。
Rare earth carboxylates, such as caprylate, stearate and naphthenate catalyst system composed of conjugated diene polymerization has good activity and orientation effect. However, there is a third component in the system, usually aluminum alkyl chloride. Its role is to exchange carboxyl group with carboxylate, which is the necessary condition to form active center. The composition of rare earth chloride system because of its composition contains chloride ions and excluded the use of the third component, thus simplifying the polymerization process is conducive to the study of the reaction between the system components. However, not all chlorinated rare earths are suitable for this study because most of the rare earth chloride complexes are insoluble in inert organic solvents. For example, rare earth chloride compounds have high activity for the polymerization of conjugated dienes. However, it is difficult to study the reaction of rare earth chloride compounds with aluminum alkyls.