乙二亚甲基-双(十六烷基二甲基溴化铵)稀水溶液的特性

Characteristics of Ethanediyl-α, β-bis(cetyldimethylammonium bromide) Dilute Aqueous Solution

合成并表征了阳离子Gemini表面活性剂乙二亚甲基-α,β-双(十六烷基二甲基溴化铵)(16-2一16)。用表面张力和粘度法确定了其cmc,通过表面张力曲线计算了16-2-16的表面吸附量、吸附分子面积和胶束形成自由能;并用悬滴法测定了16-2-16在空气表面和十二烷界面的动态表(界)面张力。用改进的Washburn方法测定16-2-16水溶液在硅胶粉末表面的接触角,并进一步讨论了16-2-16在硅胶表面的吸附引起的润湿性变化。探讨润湿性变化与动态张力的关系。将16-2-16与溴代十六烷基三甲胺(CTAB)做比较:两种物质在含油硅胶粉末上引起的最高脱油率(实验室模拟驱油)均发生在cmc附近,但16-2-16的最高脱油率是68％,CTAB的是63％。而所用CTAB的cmc比16-2-16的约大50倍,也就是说用16-2-16可以获得更高的脱油率。

Cationic Gemini surfactant, ethanediyl-α, β-bis(cetyldimemylammonium bromide) (16-2-16), was synthesized and characterized. The dynamic surface and interface tensions have been measured using pendant drop method on the air-water surface and dodecane-water interface. The relative contact angle of the aqueous solution on the silica gel powder has been obtained by modified Washburn method. The relationship between the contact angle and the dynamic surface (interface) tension has been discussed. Compared with conventional cationic surfactants, cetyldimethylammonium bromide (CTAB, cmc 1. 0 × 10-3mol· L-1), 16-2-16 has very low cmc value (1.8 × 10-5 mol ·L-1). The most hydrophilic condition between the surfactant aqueous solution and the modified silica powder appears near the cmc for both 16-2-16 and CTAB. The best laboratory mimic oil recovery (Fig. 1 and Table 2) is also reached around the cmc for the two surfactants, but the efficiency for 16-2-16(68% ) is higher than the one for CTAB (63% ).