氯化1-氨基聚醚-3-甲基咪唑离子液体的制备与催化性能

摘要

首先以环氧氯丙烷为原料，通过开环聚合得聚环氧氯丙烷（PECH），再通过溴化和氨化等方法得到端氨基的聚环氧氯丙烷，再将其与N-甲基咪唑反应，制备氯化1-氨基聚醚-3-甲基咪唑离子液体（[H2N-PECH-MIM]Cl）催化剂，并利用红外（IR）和核磁（NMR）对其化学结构进行表征，利用热重分析仪（TGA）和凝胶渗透色谱仪（GPC）对其热性能和分子量进行了测试。然后用制备的高分子离子液体[H2N-PECH-MIM]Cl催化环氧丙烷与二氧化碳合成碳酸丙烯酯，以纯度、转化率、选择性和转化频率为考察指标，研究催化温度、压力、循环使用次数对催化性能的影响，并比较了其与溴化1-乙胺基-3-甲基咪唑离子液体[AeMIM]Br的催化性能。结果表明，制备的高分子催化剂[H2N-PECH-MIM]Cl 结构正确，产率为71%，其催化性能远远优于小分子离子液体[AeMIM]Br，可在不用助催化剂的温和条件下即可高效完成催化过程，且循环使用10次基本不影响其催化活性。当催化温度为90℃，压力为1.8MPa，用量为1.0%时，纯度为99.0%，转化率为100%，选择性高达96.9%，转化频率TOF为3848h-1。%Polyepichlorohydrin(PECH)was synthesized by ring-opening polymerization with epoxy chloropropane. Then the amino-terminal polyepichlorohydrin was obtained by bromination and ammonification,and the polymer catalyst of chloride 1-amino polyether-3-methyl imidazole ionic liquid([H2N-PECH-MIM]Cl) was prepared from the amino-terminal polyepichlorohydrin and N-methyl imidazole. Finally,IR and NMR were used to characterize the chemical structure of [H2N-PECH-MIM]Cl,while TGA and GPC were used to determinate the thermal properties and molecular weight. Propylene carbonate was synthesized from propylene epoxide and carbon dioxide with the catalyst of [H2N-PECH-MIM]Cl. The effects of temperature,pressure and the number of recycles on catalytic properties were studied in terms of purity,conversion,selectivity and the turnover frequency(TOF). The catalytic performance of [H2N-PECH-MIM]Cl and [AeMIM]Br was compared. The results showed that the chemical structure of the prepared [H2N-PECH-MIM]Cl was right,and the yield was 71% and the catalytic performance was far better than that of the organocatalyst of [AeMIM]Br. [H2N-PECH-MIM]Cl could achieve the catalytic process efficiently without assistant catalyst and could be used 10 times under mild conditions. The purity,conversion rate,the selectivity and TOF were 99.0%,100%,96.9% and 3848h–1 respectively at 90℃,and 1.8MPa with the catalyst dosage of 1.0%.