木质素两性表面活性剂的合成及表面物化性能

以十二烷基二甲基叔胺、环氧氯丙烷为原料,合成了中间体(2,3-环氧丙基)十二烷基二甲基氯化铵(DMAC),再与磺化木质素(SL)酚羟基反应,合成了木质素两性表面活性剂LAS。通过正交实验确定了最佳合成条件:以丙酮为溶剂,n(SL)∶n(DMAC)=1∶1.1,反应时间3h,pH=12,反应温度55℃,产物中氮质量分数达2.25%。通过元素分析、傅立叶变换红外光谱、UV,确证了目的产物结构。测定产物的临界胶束质量浓度CMC为3g/L,γCMC为21.11mN/m,HLB值为10。表明所合成的木质素两性表面活性剂具有较高的表面活性。

Synthesis of lignin amphoteric surfactant and measurements of their physic-chemical properties

(2,3-Epoxypropyl) dimethyl-ammonium chloride(DMAC) was synthesized with N,N-dimethyl dodecylamine and epichlorohy as raw materials in this article.Then the LAS(lignin amphoteric surfactant) was prepared by the DMAC with SL(sulphonated lignin).Through the orthogonal experiment,the optimal preparation condition was investigated:using acetone as the solvent,n(SL):n(DMAC) was 1:1.1,reaction time was 3 h,reaction temperature 55 ℃,pH value was 12.The nitrogen content of LAS reached 2.25%.The structure of the product was characterized by FTIR spectrum,UV and elementary analysis.The surface activities of the product were measured:critical micelle concentration(CMC) 3 g/L,their surface tension was 21.11 mN/m,HLB was 10.Results showed that LAS exhibited a higher surface activity.