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前言用过渡金属铁化合物催化丁二烯聚合始于1960年,迄今已是廿多年的历史了。但多年来,取得较大成功的例子却不多。铁、钴和镍虽然同属周期表中第Ⅷ族,但铁表现出的聚合特性与钴和镍却明显不同。一些用钴和镍能够合成出聚丁二烯的催化体系,换成铁则或者根本不发生聚合,或者聚合物收率很低,或者仅得到低聚产物。由此看来,铁催化体系的活性中心结构一定与钴、镍等催化体系有所差别,活性中心的稳定性也较差。铁体系与钴、镍等体系的明显差别在于前者一般需要加入配体,使活性中心稳定。多年来,人们一直在探索铁系,主要还是寻找合适的配体,使其活性提高。由于配体的加入,铁催化体系的聚合机理与钴、镍等过渡金属体系的聚合机理有所不同。因此,探讨
Introduction Transition polymerization of butadiene catalyzed by transition metal iron compounds began in 1960 and is now over 20 years old. But over the years, there have been few examples of achieving greater success. Iron, cobalt, and nickel, while belonging to Group VIII of the periodic table, exhibit significantly different polymerization characteristics from cobalt and nickel. Some cobalt and nickel can be synthesized polybutadiene catalytic system, replaced with iron or without polymerization at all, or the polymer yield is very low, or only oligomerization products. Seen in this light, the catalytic structure of the iron catalytic system must have a catalytic system with cobalt, nickel and other differences, the stability of the active center is also poor. Iron system and cobalt, nickel and other obvious difference is that the former generally need to join the ligand, so that the active center stability. Over the years, people have been exploring the iron system, mainly looking for the right ligand to increase its activity. Due to the addition of the ligand, the polymerization mechanism of the iron-catalyzed system is different from the polymerization mechanism of the transition metal system such as cobalt and nickel. Therefore, to explore