摘要
以TiCl4 、SnCl4 、BF3OEt2 和AlCl3等为引发剂在不同溶剂中引发环戊二烯阳离子聚合 ,借助核磁共振谱图研究了各种因素对产物链结构的影响。结果表明 ;随催化剂酸性的增强 ,产物中 1,2 -结构环戊烯的比例升高 ,顺序为Al Cl3>SnCl4 >TiCl4 >BF3OEt2 ,而相对分子质量的变化规律相反 ,这与增长过程离子对的状态有关系。在二氯甲烷溶剂中 ,1,2 -结构的质量分数高达 44 9% 。
Cationic polymerization of 1,3-cyclopentadiene was studied with Friedel-Crafts catalysts,inclu ding TiCl 4,SnCl 4,BF 3OEt 2 and AlCl 3 and the influence of polymerization conditions on polymer structure was investigated. 1,2-structure cyclopentene of oligo(1,3-cyclopentadiene)could be estimated from its 1H NMR spectrum.The content of 1,2-structure varied with catalyst:AlCl 3>SnCl 4>TiCl 4>BF 3OEt 2.This might be explained in terms of the tightness of the growing ion pair.A more acidic catalyst was considered to give an ion pair of weaker interaction and a less acidic catalyst to give one of stronger interaction.The gegeinon would interact with the cation more strongly in a tighter ion pair,causing localization of the positive charge,while in a looser ion pair the positive charge of the growing ion par would tend to be more delocalized for want of the stronger interaction.The growing ion pair was better solvated with polar methylene chloride than with toluene,suggesting a free nature of the ion pair and a higher 1,2-structure content.The molecular weight data also supported the change in the structure of the ion pair under similar conditions.
出处
《石油化工》
CAS
CSCD
北大核心
2001年第8期608-611,共4页
Petrochemical Technology
基金
河北省教育厅博士基金资助项目
关键词
阳离子聚合
环戊二烯
环戊烯
核磁共振谱图
链结构
cationic polymerization
1,3-cyclopentadiene
1,2-structure cyclopentene, 1H NMR
