棕榈酰胺丙基甜菜碱两性表面活性剂的合成、表征与性能

Synthesis, Characterization and Properties of Palmitamidopropyl Betaine Amphoteric Surfactant

摘要:

以天然产物棕榈酸、N,N-二甲基-1,3-丙二胺为原料通过酰胺化反应合成中间产物棕榈酰胺丙基二甲基叔胺，再与氯乙酸钠反应合成了两性表面活性剂——棕榈酰胺丙基甜菜碱（PAPB），并考察了反应温度和时间、反应物摩尔比、催化剂用量和4A分子筛等因素对合成中间产物的影响；通过红外光谱和核磁共振对产物结构进行了表征；测试合成产物及其复配体系的表面活性。得到的酰胺化反应的最佳条件为：反应温度160℃、反应时间10 h、n(N,N-二甲基-1,3-丙二胺): n(棕榈酸)=1.05:1，KOH用量为反应物总质量的0.5%，在该条件下，棕榈酸的转化率可达92.41%；产物的临界胶束浓度CMC为1.12×10-4 mol•L-1，γCMC为31.63 mN•m-1，对苯的增溶性能为X=4980mL/mol。

Abstract:

The palmitamidopropyl betaine (PAPB) type amphoteric surfactant was synthesized by sodium choloroacetate and palmitamidopropyldimethyl tertiary amine that was synthesized by an amidation with palmitic acid and N,N-dimethyl-1,3-propanediamine as raw material. The effects of reaction temperature and time, the molar ratio of palmitic acid to N,N-dimethyl-1,3-propanediamine, the amount of catalyst, 4 A molecular sieves on conversion of palmitic acid were studied. Meanwhile, the structure of product was characterization by FTIR and 1HNMR, and properties of palmitamidopropyl betaine and the mixed surfactant systems were investigated. The results showed that the optimum conditions of amidation reaction were screened out as follows: reaction temperature of 160℃ and reaction time of 10 h, the molar ratio of N,N-dimethyl-1,3-propanediamine to palmitic acid 1.05:1, the amount of catalyst KOH of 0.5%. Under the above conditions, the conversion of palmitic acid was 92.41%. The critical micelle concentration and surface tension of palmitamidopropyl betaine were 1.12×10-4 mol•L-1 and 31.63 mN•m-1, respectively, and its solubilization capacity of benzene was 4980mL/mol.