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用紫外可见光谱法考察了MoO_2Br_2-Al(i-Bu)_2OPhCH_3(-m)催化体系中添加第三组分-烯丙基卤(A11yl-X),对丁二烯聚合的影响.结果表明,MoO_2Br_2的乙酸乙酯溶液在340nm和780nm处有两个特征吸收峰.其中780nm处归属为Mo(V)的自旋允许d-d跃迁吸收峰.烯丙基卤能与Mo形成π络合物,随Al/Mo增加,其电荷迁移峰由340nm移向380nm,且烯丙基卤和丁二烯可分别与Mo(Ⅲ)形成的π络合物,其特征吸收峰均在380nm处.同时表明,Al(i-Bu)_2OPhCH_3(-m)易与烯丙基溴反应,可使烯丙基溴-Mo(Ⅲ)络合物解络合.
The effects of the addition of the third component-allyl halide (A11yl-X) on the polymerization of butadiene were investigated by UV-Vis spectroscopy. The results showed that the addition of A11yl-X to the MoO_2Br_2-Al The ethyl acetate solution of MoO 2 Br 2 has two characteristic absorption peaks at 340 nm and 780 nm, of which the spin assigned to Mo (V) at 780 nm allows for the dd transition absorption. Allyl halides can form π complexes with Mo, Al / Mo increases, the charge transfer peak shifts from 340nm to 380nm, and the allyl halide and butadiene can form π complexes with Mo (Ⅲ) respectively, and their characteristic absorption peaks are at 380nm.At the same time, Al (i-Bu) _2OPhCH_3 (-m) is easily reacted with allyl bromide to decompose the allyl bromide-Mo (III) complex.