Abstract: Disclosed are a pH-responsive amphoteric surfactant N-lauryl-(?-alkyl)-?-aminopropionic acid and a preparation method and uses thereof. An alkylamine and a solvent are added to a three-necked flask, stirred for complete dissolution, slowly dropwise added with methyl ?-alkyl-acrylate and reacted at room temperature after the ice-water bath is removed. The reaction mixture is refluxed in water bath and evaporated under rotation to remove the solvent and the residual methyl ?-alkyl-acrylate to give N-lauryl-(?-alkyl)-?-aminopropionic acid. Then N-lauryl-(?-alkyl)-?-aminopropionic acid and water are added to a three-necked flask, slowly dropwise added with a sodium hydroxide solution and reacted in water bath to give a crude product, which is filtered and dried to give a purified surfactant sodium N-lauryl-(?-alkyl)-?-aminopropionate. This surfactant is suitable for the foamed acid system and its performance can be switched by adjusting pH due to pH sensitivity.

Abstract: Disclosed are a pH-responsive amphoteric surfactant N-lauryl-(?-alkyl)-?-aminopropionic acid and a preparation method and uses thereof. An alkylamine and a solvent are added to a three-necked flask, stirred for complete dissolution, slowly dropwise added with methyl ?-alkyl-acrylate and reacted at room temperature after the ice-water bath is removed. The reaction mixture is refluxed in water bath and evaporated under rotation to remove the solvent and the residual methyl ?-alkyl-acrylateto give N-lauryl-(?-alkyl)-?-aminopropionic acid. Then N-lauryl-(?-alkyl)-?-aminopropionic acid and water are added to a three-necked flask, slowly dropwise added with a sodium hydroxide solution and reacted in water bath to give a crude product, which is filtered and dried to give a purified surfactant sodium N-lauryl-(?-alkyl)-?-aminopropionate. This surfactant is suitable for the foamed acid system and its performance can be switched by adjusting pH due to pH sensitivity.