N-酰基苯丙氨酸钠表面活性剂的合成和性能研究

Synthesis and properties of sodium N-acylphenylalanine surfactants

以十二酰氯、十四酰氯、十六酰氯和苯丙氨酸为原料,肖顿鲍曼法合成了3种不同碳链长度的N-酰基苯丙氨酸钠表面活性剂:N-十二酰基苯丙氨酸钠(C12PheNa)、N-十四酰基苯丙氨酸钠(C14PheNa)和N-十六酰基苯丙氨酸钠(C16PheNa)。通过红外光谱(FTIR)、核磁共振氢谱(1H NMR)对产物的结构进行了表征。考察了三种表面活性剂的表面活性、泡沫、乳化、润湿性能。结果表明,随着碳链长度的增加(C12~C16),N-酰基苯丙氨酸钠表面活性剂的临界胶束浓度(cmc)由0.15 mmol/L减少至0.02 mmol/L,对应的表面张力(γcmc)由34.56 mN/m降低至31.52 mN/m;随着烷基碳链的增长,乳化性能越好,润湿性能越差;起泡性能随着烷基链的增加呈现先增加后减少,泡沫稳定性随着烷基链的增加而增加。

Using dodecanoyl chloride,tetradecanoyl chloride,hexadecanoyl chloride and phenylalanine as raw materials,three kinds of sodium N-acylphenylalanine surfactants with different carbon chain lengths were synthesized by the Shawton Baumann method:sodium N-lauroyl phenylalaninate(C 12 PheNa),sodium N-tetradecanoyl phenylalaninate(C 14 PheNa),sodium N-hexadecanoyl phenylalaninate(C 16 PheNa).The structure of the product was characterized by infrared spectroscopy(FTIR)and nuclear magnetic resonance spectroscopy(1H NMR).The surface activity,foaming,emulsifying and wetting properties of three surfactants were investigated.The results show that the critical micelle concentration(cmc)of sodium N-acylphenylalanine surfactant decreases from 0.15 mmol/L to 0.02 mmol/L with the increase of carbon chain length(C 12~C 16).The surface tension(γcmc)is from 34.56 mN/m to 31.52 mN/m.With the increase of alkyl carbon chain,the better the emulsifying property,the worse the wetting property.Foaming performance increases first and then decreases with the increase of alkyl chain,foam stability increases as the alkyl chain increases.