A Novel Alkyl Sulphobetaine Gemini Surfactant Based on S‐triazine: Synthesis and Properties

A series of alkyl sulphobetaine Gemini surfactants C n ‐GSBS ( n = 8, 10, 12, 14, 16) was synthesized, using aliphatic amine, cyanuric chloride, ethylenediamine, N , N ′‐dimethyl‐1,3‐propyldiamine and sodium 2‐chloroethane sulfonate as main raw materials. The chemical structures were confirmed by FT‐IR, 1 H NMR and elemental analysis. The Krafft points differ markedly with different carbon chain length, for C 8 ‐GSBS, C 10 ‐GSBS and C 12 ‐GSBS are considered to be below 0 °C and C 14 ‐GSBS, C 16 ‐GSBS are higher than 0 °C but lower than room temperature. Surface‐active properties were studied by surface tension and electrical conductivity. Critical micelle concentrations were much lower than dodecyl sulphobetaine (BS‐12) and decreased with increasing length of the carbon chain from 8 to 16, and can reach a minimum as low as 5 × 10 −5 mol L −1 for C 16 ‐GSBS. Effects of carbon chain length and concentration of C n ‐GSBS on crude oil emulsion stability were also investigated and discussed.