脂肪酸-多乙烯胺酰胺化反应  

Fatty Acid-Polyethylene Polyamine Amidation Reaction

作　　者：付长征 王清颐 匡正 翟光群 FU Changzheng;WANG Qingyi;KUANG Zheng;ZHAI Guangqun(College of Materials Science and Engineering,Changzhou University,Changzhou,Jiangsu 213164,China;Wuxi Shengyi Synthetic Materials Co.,Ltd.,Wuxi,Jiangsu 214106,China)

机构地区：[1]常州大学,材料科学与工程学院,江苏常州213164 [2]无锡市盛意合成材料有限公司,江苏无锡214106

出　　处：《塑料》2025年第2期117-123,共7页Plastics

摘　　要：以正己酸与二乙烯三胺(DETA)为原料,在160℃条件下,采用一步法合成低分子量聚酰胺树脂,利用傅里叶变换红外光谱、紫外吸收光谱、核磁共振氢谱等跟踪反应过程,研究反应机制。结果表明,当正己酸与DETA摩尔比为2.0∶1.5时,羧基与伯胺酰胺化反应速率远大于羧基与仲胺酰胺化的反应速率,这表明,反应产物以仲酰胺为主,同时生成少量叔酰胺,但很快与未反应的伯胺发生酰胺交换反应,生成仲酰胺;当胺过量时,反应产物仍以酸与胺2∶1的比例反应生成的三聚体为主;随着反应的进行,部分酰胺脱水环化为咪唑啉,酰胺环化率分别为加热1 h后的3.5%、加热2 h后的11.25%及最终加热3 h后达到30.52%。随着脂肪酸碳链的增长,位阻效应逐渐增强,形成咪唑啉的速率逐渐降低,叔酰胺占比提高,在进一步反应中均逐渐降低。Low-molecular-weight polyamide resin was synthesized by one-step method at 160℃using hexanoic acid and diethylenetriamine(DETA)as raw materials.The process was tracked by Fourier-transformed infrared spectroscopy,ultraviolet absorption spectroscopy and proton nuclear magnetic resonance spectroscopy,to investigate the mechanism.The results showed that when the molar ratio of hexanoic acid to DETA was 2.0∶1.5,the amidation rate of carboxyl group and primary amine was much higher than that of carboxyl group and secondary amine.Thus,secondary amide was the main product,accompanied by a small amount of tertiary amide.However,the latter steadily exchanged with free amine to form secondary amide.Even in the presence of excess DETA,the product was dominated by diamide.With the progress of the reaction,part of the amide dehydrated into imidazoline,the amidation cyclization rates were 3.5%after heating for 1 h,11.25%after heating for 2 h,and eventually reached 30.52%after heating for 3 h.However,a long alkyl chain of fatty acid hindered the formation of imidazoline,and promoted the formation of tertiary amide moiety,but they also gradually exchange with free amine.

关 键 词：反应机理 聚酰胺树脂 酰胺化反应 咪唑啉 脂肪酸 

分 类 号：TQ323.6[化学工程—合成树脂塑料工业]