镍催化体系合成顺式聚丁二烯的研究——Ⅵ.磁化率法探讨镍系各组分间的相互作用

SYNTHESIS OF cis-1,4-POLYBUTADIENE WITH NICKEL CATALYST VI. STUDY OF THE INTERACTIONS BETWEEN THE COMPONENTS IN THE NICKEL CATALYST SYSTEM BY THE METHOD OF MAGNETIC SUSCEPTIBILITY

本工作用磁化化率法结合聚合实验,研究了Ni(naph)_2-BF_3·OEt_2-Al(i-Bu)_3 催化体系各组分间的相互作用。结果表明,Ni(naph)_2汽油溶液为顺磁性体系;BF_3·OEt_2 能分别与 Ni(Ⅱ)和Ni(0)形成络合物,但前者为顺磁性络合物;丁二烯有促进 Ni(Ⅱ)的还原,稳定 Ni(Ⅰ),阻止BE_3·OEt_2对 Ni(0)的聚沉,提高催化活性的作用。

The interactions between the components in the Ni(naph)2-BF3·OEt2-Al(i-Bu)3 catalyst system during the synthesis of cis-1,4-polybutadiene were studied by the method of magnetic susceptibility. The results show that the solution of nickel cycloakanes-carboxylate in gasoline is a paramagnetic system. The BF3·OEt2 can react with both Ni(Ⅱ) and Ni (0) to form complexes; and the former complex is a paramagnetic.In the polymerization system,the butadiene has the effect of promoting the reduction of Ni(Ⅱ),stabilizing the Ni(Ⅰ),and preventing the precipitation of Ni(0) caused by BF3·OEt2, resulting in the increase in the catalyst activity.