不同酯化度的酯基季铵盐阳离子表面活性剂的制备及性能

实验以十二烷基二甲基叔胺(NDT)与环氧氯丙烷(ECH)为原料,合成中间体(2,3-环氧丙基)十二烷基二甲基氯化铵。经正交实验确定的最佳合成条件为:以丙酮为溶剂,反应时间4 h,反应温度30℃,n(NDT):n(ECH)=1:1;再与长链饱和烷基脂肪酸反应,合成不同酯化度的酯基季铵盐阳离子表面活性剂(Ⅰ、Ⅱ)。降解实验结果表明,酯基季铵盐阳离子表面活性剂(Ⅰ、Ⅱ)降解性能优异,降解性随着疏水链的增长而减小,属易生物降解的阳离子表面活性剂。

SYNTHESIS AND PROPERTIES OF QUATERNARY AMMONIUM SALT CATIONIC SURFACTANT WITH DIFFERENT ESTERIFICATION DEGREE

The intermediate, (2,3-epoxypropyl) dimethyl-ammonium chloride, was synthesized with N,N-dimethyl dodecylamine (NDT) and epichlorohydrin(ECH) as raw materials. Through orthogonally arranged experiments, the optimal preparation conditions were found as follows., with acetone for solvent, n(NDT) :n(ECH)=1: 1, reaction time 4 h and reaction temperature 30 ℃. The target product quaternary ammonium salt cationic surfactants (Ⅰ and Ⅱ) with different esterification degree were obtained by reacting the intermediate with lauric acid. Structures of the products were characterized by elemental analysis, infrared spectrum, 1H NMR and ~(13)C NMR. The critical micelle concentrations were 8.91×10~(-4) and 9.37×10~(-4) mol/L, and γ_(cmc) were 34. 12 and 39.76 mN/m for Ⅰ and Ⅱ , respectively. The results showed that the quaternary ammonium salt cationic surfactant with different esterification degrees had excellent surface activity. Degradation testing results showed that the quaternary ammonium salt cationic surfactant (Ⅰ and Ⅱ) exhibited excellent degradation performances. Degradable ability decreased with the increase of the hydrophobic proportions.