新型双核苊-二亚胺镍催化剂合成及催化乙烯聚合的研究

Synthesis a New Bi-nuclear Acenaphthene-diimine/nickel Catalyst and Its Catalysis on Ethylene Polymerization

将苊醌和4,4′-亚甲基-二(2,6-二异丙基苯胺)通过席夫碱缩合反应,采用硅胶柱分离得到双核苊-二亚胺配体[H2NC6H2-3,′5-′d i-R-CH2-3,5-d i-R-C6H2-N=C(Nap)-(Nap)C=N-3,5-d i-R-C6H2-CH2-3,′5-′d i-R-C6H2-N=C(Nap)-(Nap)C=N-3,5-d i-R-C6H2-CH2-3,′5-′d i-R-C6H2NH2],Nap为1,8-naphthd iyl;R:CH(CH3)2}(L)。在N2保护下,L与(DME)N iB r2反应,制备了一种新型双核苊二亚胺镍配合物N i2LB r4。通过1H NMR,13C NMR,EA等对配体及配合物进行了表征。研究了该催化剂以通用烷基铝,而不用昂贵的MAO为助催化剂的催化体系对乙烯聚合的催化性能,结果发现其对乙烯的聚合具有很高的活性,最高可达1.76×106g.mol-1.h-1,聚合条件如:温度、助催化剂的种类、n(A l)/n(N i)等对聚合反应及产物的结构有较大影响。

A bi-nickel-centre catalyst was prepared by Schiff-base condensation of acenaphthenequinone with 4, 4＇-methylene-bis （2, 6-diisopropyl aniline）, and subsequent metathesis reaction with （DME） NiBr2. The complex was characterized by ^1H and ^13 C NMR and EA. The distance of the new catalyst between every two active centres was controlled to result in a micro chemical environment of nickel centre being regulated. The catalyst could be used to polymerize ethylene with high activity using diethylaluminum chloride as cocatalyst at lower Al/Ni ratios and high branched polyethylenes can be obtained. The highest catalytic activity was high up to 1.76 × 10^6 g ·mol^-1· h^-1 at 40 ℃ with Al/Ni mole ratio at 1 000. It was found that polymerization conditions such as the cocatalyst, Al/Ni ratio, and temperature had a pronounced effect on catalytic activity and properties of the produced polyethylenes.