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用紫外可见光谱法对钨催化体系[Bd+加氢汽油+WCl_4(OC_8H_(17)_2~+Al(i-Bu)_3]各组分间的相互作用进行了初步的探讨,研究表明丁二烯与钨未发生络合反应。通过聚合实验,发现随Al/W比变化,在λ=400-800nm范围内存在两种不同类型的吸收光谱曲线:Al/W<3,出现非还原型曲线,无催化活性;Al/W=4-8,出现还原型曲线,有较好的催化活性。采用钼催化体系可获得等规度较好的间同1,2—聚丁二烯,这方面已有过报道。而钨催化体系用于丁二烯聚合,可获得1,2—链节含量为80％左右,全同立构体含量在60％以上的聚合物。但是,有关催化机理和活性中心的价态和结构等问题,尚待进一步研究。本文用紫外可见光谱法对该体系的作用机理进行了初步的探讨。
The interaction between various components of tungsten catalyst [Bd + hydrogenated gasoline + WCl_4 (OC_8H_ (17) _2 ~ + Al (i-Bu) _3] was studied by UV-Vis spectroscopy. The results showed that butadiene And did not occur complex reaction with tungsten.According to the polymerization experiment, we found that there are two different types of absorption spectra in the range of λ = 400-800nm with Al / W ratio change: Al / W <3, non-reduction curve appears, No catalytic activity; Al / W = 4-8, there is a reduction curve, and has better catalytic activity.Using molybdenum catalyst system can be obtained with good isotactic 1,2-polybutadiene, which has been There are reports .While tungsten catalytic system for the polymerization of butadiene can be obtained 1,2-link content of about 80%, isotactic content of more than 60% of the polymer However, the catalytic mechanism and activity The valence and structure of the center and other issues, pending further study.In this paper, UV-visible spectroscopy of the mechanism of the mechanism of a preliminary study.