Ai Youhong, Zhan Yangyang, Cai Dongbo, Chen Shouwen
Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials & Key Laboratory for the Synthesis and Application of Organic Functional Molecules (Ministry of Education), College of Chemistry & Chemical Engineering, Hubei University, Wuhan 430062, China.
State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan 430062, China.
Polymers (Basel). 2024 Dec 25;17(1):10. doi: 10.3390/polym17010010.
The presented work discusses the highly efficient esterification of poly (γ-glutamic acid) (γ-PGA) with alkyl halides at room temperature. The esterification reaction was completed within 3 h, and the prepared γ-PGA esters were obtained with excellent yields (98.6%) when 1,1,3,3-tetramethylguanidine (TMG) was used as a promoter. The influence of the amount of TMG, solvent, reaction conditions, and alkyl halides on the esterification reaction was examined. It was found that polar aprotic solvents, such as -Methylpyrrolidone (NMP) and 1,3-Dimethyl-2-imidazolidinone (DMI), were favorable for the esterification. Non-polar or weakly polar solvents (i.e., dichloroethane, acetonitrile) were not favorable for the esterification. Water as a solvent had a negative effect on esterification. The reactivity of bromine halogenated compounds was higher than that of chlorine halogenated compounds but lower than that of iodine halogenated compounds. The structures of the prepared γ-PGA ester were confirmed by H NMR and FT-IR spectroscopy. Thermal stability and hydrophobic properties of the resulting product were tested. The results showed that the prepared γ-PGA propyl ester had high thermal stability (up to 267 °C) and showed good hydrophobicity (contact angle 118.7°).
本文工作讨论了聚（γ-谷氨酸）（γ-PGA）与卤代烷在室温下的高效酯化反应。酯化反应在3小时内完成，当使用1,1,3,3-四甲基胍（TMG）作为促进剂时，制备的γ-PGA酯具有优异的产率（98.6%）。考察了TMG用量、溶剂、反应条件和卤代烷对酯化反应的影响。发现极性非质子溶剂，如N-甲基吡咯烷酮（NMP）和1,3-二甲基-2-咪唑啉酮（DMI），有利于酯化反应。非极性或弱极性溶剂（即二氯乙烷、乙腈）不利于酯化反应。水作为溶剂对酯化反应有负面影响。溴代卤化物的反应活性高于氯代卤化物，但低于碘代卤化物。通过1H NMR和FT-IR光谱对制备的γ-PGA酯的结构进行了确认。测试了所得产物的热稳定性和疏水性。结果表明，制备的γ-PGA丙酯具有较高的热稳定性（高达267℃），并表现出良好的疏水性（接触角118.7°）。
