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Ziegler-Natta型Ni(naph)_2-Al(i-Bu)_3-BF_3OEt_2(简称Ni-Al-B)催化体系在丁二烯(Bd)聚合过程中,活性中心络合物上氟的状态和数量控制着单体配位、引发、增长和链转移等步骤。文献[1—6]曾指出该体系显高催化活性的Al/B(mol比)范围在0.5—1.0之间,即F/Al=6—3.Al/B>1或F/Al<3时,聚合活性显著降低。最近,我们采用了添加酸、醇、酚和酯类等方法来改进体系中B组分的分散及氟的反应性,Al/B显著拓宽为0.3—3,氟的利用率得到提高。在此基础上,本文将讨论用~(19)F-NMR法研究氟
In the polymerization of butadiene (Bd) with Ziegler-Natta type Ni (naph) _2-Al (i-Bu) _3-BF_3OEt_2 (Ni-Al-B) catalyst system, the state of fluorine on the active site complex and The number controls the monomer coordination, initiation, growth and chain transfer steps. The literature [1-6] pointed out that the high catalytic activity of the system Al / B (mol ratio) in the range of 0.5-1.0, that F / Al = 6-3. Al / B> 1 or F / Al <3 The polymerization activity is significantly reduced. Recently, we have adopted the addition of acids, alcohols, phenols and esters to improve the dispersion of B components and the reactivity of fluorine in the system. Al / B is broadened significantly to 0.3-3 and the utilization of fluorine is improved. On this basis, this article will discuss ~ (19) F-NMR study of fluorine