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本文用ESR、~1H-NMR及IR研究了Fe(phen)Cl_3-(i-C_4H_9)_3Al体系催化丁二烯聚合的机理。ESR谱表明,聚合活性中心上的铁为Fe(Ⅱ)。同时观察到自由基的信号,为其还原历程提供了证据。体系中不存在丁二烯时有很宽的ESR信号(ΔH_(pp)=900G)、加入丁二烯时可以观察到一窄信号(ΔH_(pp)=50G),二者有明显区别。提出了Fe(phen)Cl_3-(i-C_4H_9)_3Al体系催化丁二烯聚合的反应机理,两个体系的~1H-NMR和IR谱图的比较证实了这个机理。
In this paper, the mechanism of butadiene polymerization catalyzed by Fe (phen) Cl_3- (i-C_4H_9) _3Al was studied by means of ESR, 1H-NMR and IR spectra. ESR spectra showed that Fe (II) was the active iron in the polymerization center. At the same time, we observed the signals of free radicals and provided evidence for the reduction process. In the absence of butadiene, there is a very wide ESR signal (ΔH_ (pp) = 900G). A narrow signal (ΔH_ (pp) = 50G) was observed when butadiene was added. The reaction mechanism of butadiene polymerization catalyzed by Fe (phen) Cl_3- (i-C_4H_9) _3Al was proposed. The comparison of ~ 1H-NMR and IR spectra of the two systems confirmed this mechanism.