十二烷基二甲基苄基氯化铵结构修饰及性能研究

Study on the structural modification and performance of dodecyl dimethyl benzyl ammonium chloride

以苯胺、十二酸、N,N-二甲基乙醇胺等为原料合成了十二烷基二甲基苄基氯化铵(1227)结构修饰的阳离子表面活性剂(I10,I12,I14,I16)。利用1H-NMR和FT-IR对目标产物结构进行表征。在25℃条件下,分别用电导率法和表面张力法测定目标产物的临界胶束浓度(CMC)和表面张力(γ)。结果表明,I16的CMC值最小,为4.29×10^(-5) mol·L^(-1),γCMC值为38.08 mN·m,并计算目标产物在空气-水界面上的饱和吸附量(Γmax)、单个吸附分子的最小截面积(Amin)、降低溶液表面张力的效率(pC20)和降低溶液表面张力的能力(πCMC)。在25℃条件下,测试了目标产物的泡沫性能和乳化性能。分析结果表明,I16的稳泡性能达到100%,并且乳化能力最好,分出10 mL水的时间为2505 s。对目标产物的最低抑菌浓度(MIC)进行测试,结果表明I12对枯草芽孢杆菌和大肠杆菌的MIC分别为13.5μg·mL^(-1)和32.5μg·mL^(-1),具有较高的抑菌活性。

Dodecyl dimethyl benzyl ammonium chloride(1227)structure modified cationic surfactants( I 10 , I 12 , I 14 , I 16 )were synthesized using anilin,lauric acid, N,N -dimethylethanolamine as materials.The structure of the target products were characterized by 1H-NMR and FT-IR.The critical micelle concentrations( CMC )and surface tension( γ )of target products were determined by conductivity method and surface tension method at 25℃,respectively.The results show that I 16 had the smallest CMC value,which was 4.29×10^(-5) mol·L^(-1) ,and the γ CMC value was 38.08 mN·m.The saturated adsorption amount( Γ max ),the minimum cross-sectional area of a single adsorbed molecule( A min ),the efficiency of reducing the surface tension( p C 20 )of the solution and the ability to reduce the surface tension( π CMC )of the solution of the target products at the air-water interface were calculated.The foam properties and emulsification properties of target products were investigated at 25℃.The results showed that the foam stability of I 16 reaches 100%. I 16 had the significant emulsifying ability,and the time for separating 10 mL water was 2 505 s.The minimum inhibitory concentration(MIC)of the target products were tested.The results showed that the MIC values of I 12 against Bacillus subtilis and Escherichia coli were 13.5 and 32.5 μg·mL^(-1) ,respectively.And I 12 had the better bacteriostatic activity.