联结基团对酯基型双子表面活性剂驱油性能的影响

Influences of linking groups on oil displacement performanceof ester-based Gemini surfactants

以丁二酸、辛二酸、N,N-二甲基乙醇胺、2-[2-(二甲基氨基)乙氧基]乙醇和溴代十四烷为原料,合成了具有不同联结基团的酯基型阳离子双子(Gemini)表面活性剂(GS14-EG m-14和GS14-EEG m-14(m=2,6)).通过核磁共振氢谱(1H NMR)和红外光谱(FTIR)对其结构进行表征,并利用表面张力仪、荧光光谱仪、光学接触角测量仪和界面张力仪对乳液相行为进行探究.结果表明,联结基团中乙氧基的引入会使Gemini表面活性剂的表面张力从33.50 mN/m增加到37.11 mN/m;同时,随着联结基团疏水链长度的增加,Gemini表面活性剂临界胶束浓度(CMC)逐渐增加,GS14-EG m-14的CMC最低为2.05×10-4 mol/L.乳液相行为研究表明,表面张力较低的GS14-EG m-14乳化体系可以最大限度把油滴增溶到表面活性剂形成的胶束中,形成均一稳定的乳化体系,油-水分离时间最高可达210 min.GS14-EG 6-14仅用24 min即可将油/水界面张力降低至1.55×10-2 mN/m,其最终驱油效率为54.3%.

Ester-based cationic Gemini surfactants with different linking groups(GS14-EG m-14 and GS14-EEG m-14(m=2,6)respectively)were prepared by succinic acid,suberic acid,N,N-dimethylethanolamine,2-[2-(dimethylamino)ethoxy]ethanol and bromotetradecane as raw materials.The structures were characterized by 1H NMR and FTIR,and the phase behaviors of emulsions were investigated with surface tensiometer,fluorescence spectrometer,optical contact angle measuring device and interface tensiometer.The results showed that the existence of ethoxy group in the linking group increased the surface tension of Gemini surfactant from 33.50 mN/m to 37.11 mN/m;At the same time,as the length of the hydrophobic chain of the linking group increased,the critical micelle concentration(CMC)of the Gemini surfactant gradually increased,and the CMC of GS14-EG m-14 was at least 2.05×10-4 mol/L.Emulsion phase behavior studies showed that the GS14-EG m-14 emulsification system with lower surface tension could maximize the solubilization of oil droplets into the micelles formed by the surfactant,forming a uniform and stable emulsification system,with the highest oil-water separation time 210 minutes.GS14-EG 6-14 could decrease the interfacial tension of oil/water to 1.55×10-2 mN/m within 24 minutes,and the final oil displacement efficiency of GS14-EG 6-14 was 54.3%.