脂肪酸-胺反离子耦合表面活性剂的制备与耐盐性

Synthesis and salt tolerance of fatty acid-amine counterion coupled surfactants

摘要:

长链脂肪酸钠的Krafft温度（KT）较高且对无机盐的耐受性较差，不利于低温和含盐体系中使用。为此，用十二酸（C12）分别与三甲胺（TMA）、二甲基乙胺（DMA）、甲基二乙胺（MDA）、三乙胺（TEN）、四甲基乙二胺（TMEDA）、二甲基单乙醇胺（DMEA）、甲基二乙醇胺（MDEA）、三乙醇胺（TEA）反应，得到反离子耦合表面活性剂C12-TMA、C12-DMA、C12-MDA、C12-TEN、C12-TMEDA、C12-DMEA、C12-MDEA 和C12-TEA，分别考察KT及其NaCl耐受性。结果表明：C12-TMA、C12-DMA、C12-MDA、C12-TEN、C12-TMEDA 和C12-DMEA的KT比十二酸钠（C12-Na）低；当NaCl质量浓度为25.0 g/L 时，C12-TMA、C12-DMA、C12-MDA、C12-TEN和C12-TMEDA 的KT<46 ℃；适量的NaCl能提高C12-Na、C12-TEN 和C12-TMEDA水溶液与十二烷形成乳液的稳定性，但过量NaCl则导致表面活性剂析出，C12-TEN 和C12-TMEDA 析出时NaCl质量浓度为23.0 g/L，比C12-Na 的15.0 g/L提高约53%。脂肪酸胺确实比其钠盐具有更好的NaCl耐受性。

Abstract:

Long-chain fatty acid sodium salts have high Krafft temperature (KT) and poor tolerance to inorganic salts, which is not conducive to their usages in low temperature and salt-containing systems. Therefore, dodecanoic acid (C12) were associated with trimethylamine (TMA), dimethylethylamine (DMA), methyldiethylamine (MDA), triethylamine (TEN), tetramethylenediamine (TMEDA), dimethylethanolamine (DMEA), methyldiethanolamine (MDEA), triethanolamine (TEA) to obtain counterion coupled surfactants of C12-TMA, C12-DMA, C12-MDA, C12-TEN, C12-TMEDA, C12-DMEA, C12-MDEA and C12-TEA. Both KT and NaCl tolerability were measured. The results showed that KT of C12-TMA, C12-DMA, C12-MDA, C12-TEN, C12-TMEDA and C12-DMEA were lower than that of sodium dodecanoate (C12-Na). The KT of C12-TMA, C12-DMA, C12-MDA, C12-TEN and C12-TMEDA were lower than 46 ℃ when the mass concentration of NaCl (ρNaCl) was 25.0 g/L. The appropriate amount of NaCl improved the stability of emulsions formed respectively by C12-Na, C12-TEN and C12-TMEDA solutions with dodecane, but excessive NaCl caused surfactants flocculation. The flocculation of C12-TEN and C12-TMEDA occurred when ρNaCl was 23.0 g/L, which was 53% higher than that of C12-Na (15.0 g/L). Fatty acid amines did have better NaCl tolerance than their sodium salts.