有机锂的缔合度

THE ASSOCIATION DEGREE OF ORGANOLITHIUM

本文主要论述文献中有关烷基锂、聚二烯烃基锂、聚丁二烯基氧锂及聚丁二烯基羧酸锂等的缔合度问题。作者根据文献报导数据,同时结合本人近年来的研究结果指出:同一种烷基锂在烃类溶剂中的缔合度,主要随着活性种浓度的不同,可等于2,4,6;而高分子链有机锂的缔合度,则为2,4;在给定浓度下,实测所得有机锂的缔合度,实际上是以某一缔合体为主的混合物的平均值。一般而言,有机锂的缔合度与本身的分了结构、活性种的浓度、单体浓度、测定温度和溶剂性质等因素有关。

This review deals with the association degree of organolithium including n-BuLi, polybutadienyland polyisoprenyllithiums in hydrocarbon solvent. It is well-knowm that there exists a controversy in literatures about the association degree of organolithium between experimental results obtained by Morton and Bywater respectively. However, the recent works reported by the author of this article and his colleagues show that the association degree of organolithium in hydrocarbon solvent depends mainly on the concentration of active species and its molecular structure as well as the concentration of monomer, the reaction temperature and the kind of polar additive. Therefore, generally speaking, an organolithium in a given hydrocarbon solvent is pressnted in the associated form and its average association degree N changed from 2 to 6 with the increase of its concentration and decrease with the addition of a small amount of polar additive into the abovementioned system; furthermore, in pure strong polar solvent organolithium was completely dissociated into monomeric species.