α-蒎烯阳离子聚合的二聚体研究

Study on the Dimers Formed in Cationic Polymerization of α-Pinene

研究了α－蒎烯阳离子聚合反应中二聚体的形成及其结构。结果表明，活性中心为Ｈ＋的ＡｌＣｌ３，ＣＦ３ＳＯ３Ｈ催化体系引发α－蒎烯聚合，产物中二聚体含量较高（２７～６３％）；而在引发活性中心为金属正离子的ＡｌＣｌ３／ＳｂＣｌ３复合体系的产物中，二聚体含量很低（～５％）。用制备ＧＰＣ对二聚体进行分离，进而用１３Ｃ－ＮＭＲ、１Ｈ－ＮＭＲ进行结构分析，提出了５种主要二聚体的分子结构。不同催化体系导致相似的几种二聚体，但相对含量有所不同。

The proton initiating species generated from classical Lewis acid or protonic acid catalyst systems such as AlCl3 and CF3SO3H induced large amounts ( 27～63%) of dimers along with low molecular weight oligomers of α-pinene. The antimony cation initiating species generated via the combination of AlCl3 and SbCl3 , however, gave high molecular weight oligomers with low dimer content (5%). The α-pinene dimers were separated from the products by preparative GPC and then analyzed by 13C-NMR and 1H-NMR spectroscopy. It was promised that five major dimers 1 ～5 were formed in the cationic polymerization of α-pinene.