Mechanism of monomer insertion for heterogeneous isospecific Ziegler-Natta catalytic models
Mechanism of monomer insertion for heterogeneous isospecific Ziegler-Natta catalytic models
复制标题
异质同种齐格勒-纳塔催化模型的单体插入机制
DOI：
10.1016/0014-3057(91)90124-7
复制
发表时间：
1991
影响因子：
6
通讯作者：
R. Fusco
中科院分区：
文献类型：
--
作者：
V. Venditto;G. Guerra;P. Corradini;R. Fusco
先前提出的异质同种齐格勒-纳塔聚合模型与大量实验事实一致，已得到更详细的检验。特别地，已经尝试对插入步骤中配位的前手性1-丙烯分子的两个面之间的区分效果进行半定量评估。这项研究与配位步骤中模型的重新检查一起提出，该模型更详细地考虑了金属-碳键长度的假设值对立体特异性的影响。与之前的建议一致，分析表明在插入步骤中也存在对映选择性（硅烯烃在Λ位点上优先，与增长链的构型无关），而在配位步骤中不存在对映选择性。
The model previously proposed for the heterogeneous isospecific Ziegler-Natta polymerization, which agrees with a large number of experimental facts, has been examined in more detail. In particular a semiquantitative evaluation of the discriminating effects between the two faces of the co-ordinated prochiral l-propene molecule at the insertion step has been attempted. This study is presented together with a re-examination of the model at the co-ordination step, which considers in more detail the influence of the assumed values for the metal-carbon bond lengths on the stereospecificity. In agreement with previous suggestions, the analysis indicates the presence of enantioselectivity (siolefin favoured on a Λ site independently of the configuration of the growing chain) at the insertion step also in the absence of enantioselectivity at the co-ordination step.