一种pH响应性氨基酸酸液起泡剂的合成与应用

Synthesis and Application of a pH-Responsive Amino Acid Acidizing Foaming Agent

摘要:

以十二胺和甲基丙烯酸甲酯为原料，通过两步反应合成了一种pH响应性氨基酸两性表面活性剂——N-月桂基-(α-甲基)-β-氨基丙酸钠（AAS-1）。采用单因素实验进行优化，得出最优工艺条件为：n（十二胺）：n（甲基丙烯酸甲酯）=1.0:1.4，反应温度为60 ℃，反应时间为10 h。以同样的方法合成表面活性剂N-月桂基-β-氨基丙酸钠（AAS）作对比实验。采用FTIR和1HNMR对产物结构进行了表征，用表面张力仪测定不同pH下AAS和AAS-1的表面张力，得出表面张力曲线，并着重考察了α-烷基对AAS-1表面活性的影响。用Waring Blender法对AAS和AAS-1在不同pH下的泡沫性能进行了测定。结果表明：AAS和AAS-1均具有pH响应性。受α-烷基的影响，pH<7时，AAS-1的泡沫体积(V0)最高可达523 mL，泡沫半衰期(t1/2)最高可达6.25 min；pH>7时，V0<125 mL，t1/2=0 min，这说明AAS-1在酸性水介质中，起泡能力强泡沫稳定性好；在碱性水介质中却可迅速消泡，与AAS的发泡规律恰好相反，且能反复起泡消泡，可用于泡沫酸液体系充当起泡剂。

Abstract:

A pH-responsive amino acid amphoteric surfactant —— N-lauryl-(α-methyl)-β-aminopropionate (AAS-1) was synthesized by a two-step reaction using dodecylamine and methyl methacrylate. The synthesis conditions were optimized by single factor experiments. The optimal synthesis conditions were as follows: n(dodecylamine)：n(methyl methacrylate)=1.0:1.4, and the reaction temperature was 60 ℃, and the reaction time was 10 h. For comparison, N-lauryl-β-aminopropionate (AAS) was prepared in the same way. The structures of products were characterized by FTIR and 1HNMR. The surface tensions of AAS and AAS-1 under different pH were measured by surface tension meter, and the surface tension curves was acquired, and the effect of α-alkyl on its surface activity was investigated. The foam properties of AAS and AAS-1 under different pH were studied by Waring Blender method. The results shows that AAS and AAS-1 all have pH responsiveness. Affected by α-alkyl, AA-1 has a foam volume (V0) of up to 523 mL and a foam half-life (t1/2) of up to 6.25 min when pH<7, but when pH>7, V0<125 mL, t1/2=0 min. This means that, in the acidic aqueous medium, AAS-1 has good foaming ability and good foam stability but can be defoamed quickly in alkaline water medium, which is exactly the opposite of AAS foaming regularity. It can be used as a foaming agent in the foam acid system and can be repeatedly foamed and defoamed.