环碳酸酯模型化合物与胺反应的动力学研究

Kinetic Studies on Model Reactions between Cyclic Carbonate and Amines

以聚乙二醇单甲醚(mPEG)、丁二酸酐以及碳酸甘油酯为原料,合成了端基为五元环碳酸酯的聚乙二醇功能性大单体(mPEG-GC);以mPEG-GC为碳酸酯模型化合物,研究了碳酸酯与不同类型的胺在不同温度下反应的速率常数及其动力学活化能。结果表明:碳酸酯的转化率随时间的延长、胺的用量增大、反应温度的升高而增加,随反应物浓度的增加先增加后降低;正庚胺与mPEG-GC反应的活化能最低(5.63kJ/mol);在相同温度下,环己胺与碳酸酯的反应速率常数大于2-氨基庚烷与碳酸酯体系的反应速率常数。

Functionalized poly （ethylene glycol） methyl ether end capped with five-membered cyclic carbonate （mPEG-GC） was synthesized from mPEG, succinic anhydride and glycerol-I, 2-carbonate. Reaction rate constants and activation energy were determined from the model reaction between mPEG-GC and amines at different temperatures. The carbonate conversion increased with the reaction time, amine dosage and temperature, while showed a maximum upon increasing the reactant concentration. The activation energy （E~） in the reaction of mPEG GC with heptyl amine is the lowest（5. 63 kJ/mol）. The reaction rate constant for mPEG-GC with cyclohexyl amine is larger than that with 2-aminoheptane at the same temperature