极性溶剂中微量环戊二烯的二聚反应

Dimerization of Cyclopentadiene with Low Concentration in Polar-Solvents

对微量环戊二烯(CPD)在极性溶剂二甲基甲酰胺(DMF)、甲基吡咯烷酮(NMP)和乙腈(ACN)中的二聚反应进行了研究,考察了反应温度、反应时间、溶剂中CPD初始含量对极性溶剂中微量CPD二聚反应的影响,讨论了极性溶剂的溶剂效应,并与非极性C5溶剂中常量CPD二聚反应过程进行了比较。实验结果表明,极性溶剂可以促进微量CPD二聚反应的进行,极性中等且结构简单的DMF对CPD二聚反应的促进作用最大,极性最强的NMP次之,极性最弱的ACN的促进作用最弱。在3种极性溶剂中,反应初始阶段CPD转化率和DCPD收率都随反应时间的延长、反应温度的升高和CPD初始含量的增加而增大;在105～125℃内,反应4 h后CPD的二聚反应趋于平衡。

Dimerization of low concentration cyclopentadiene （CPD） in polar solvents of N- dimethylformamide （ DMF）, N-methyl-pyrrolidone （NMP） or acetonitrile （ACN） was studied. The effects of reaction temperature, reaction time and CPD initial concentration in the solution on the dimerization in the polar solvents were investigated. The experimental results were compared with the reference data about normal concentration CPD dimerization in nonpolar C5 solvent. The results showed that the polar solvents was in favor of the dimeriation of CPD. DMF with moderate polarity and simple structure could significantly promote the dimerization, on the contrary, the effect of ACN with the smallest polarity is the weakest. In the initial reaction stage, both the CPD conversion and the dicyclopentadiene yield in the three polar solvents separately increased with the prolongation of reaction time, the rise of reaction temperature and the increase of CPD initial concentration. Between 105℃ and 125 ℃, the dimerization of CPD with low concentration was in equilibrium in the reaction 4 hours.