A process for the preparation of derivatives of halo-but-2-enoic acids and esters high in 2-ene content, several of which are novel. The esters and their derivatives are useful as promoters for the polymerization of ethylene or the copolymerization of ethylene with &agr;-olefins and, optionally, nonconjugated polyenes. The promoters can also be combined with transition metal compounds, e.g., vanadium, to form combination promoter-catalyst compounds.
一种制备高含2-烯基的卤代丁-2-烯酸及其
酯类衍
生物的方法,其中有几种是新型的。这些
酯类及其衍
生物可作为促进
乙烯聚合或
乙烯与α-烯烃和可选的非共轭多烯共聚的催化剂。这些催化剂也可以与过渡
金属化合物如
钒等组合形成组合催化剂。