Synthesis and Performance Evaluation of CO2/N2 Switchable Tertiary Amine Gemini Surfactant

Abstract A type of switchable tertiary amine Gemini surfactant, N , N ′‐di( N , N ‐dimethyl propylamine)‐ N , N ′‐didodecyl ethylenediamine, was synthesized by two substitution reactions with 3‐chloro‐1‐( N , N ‐dimethyl) propylamine, bromododecane and ethylene diamine as main raw materials. The structure of the product was characterized by FTIR and 1 H‐NMR. We also investigated the surface tension when CO 2 was bubbled in different concentrations of surfactant solution and the influence of different CO 2 volumes on surface tension under a constant surfactant concentration. Finally the surface tension curve and the related parameters were acquired by surface tension measurements. The experimental results showed that the structure of the synthesized compounds were in conformity with the expected structure of the surfactant, and displayed a better surface activity after bubbling CO 2 . The critical micelle concentration (CMC) surface tension at CMC ( γ cmc ) p C 20 (negative logarithm of the surfactant's molar concentration C 20 , required to reduce the surface tension by 20 mN/m) surface excess ( Γ max ) at air/solution interface and the minimum area per surfactant molecule at the air/solution interface ( A min ) were determined. Results indicate that the target product had good surface activity after bubbling CO 2 .