Synthesis and Surface/Interfacial Properties of Novel Dialkyl Disulfonate Gemini Surfactants Derived from 1,3,5-triazine

A series of novel dialkyl disulfonate Gemini surfactants (C-n-GSBS, n = 8, 12, 14, 16, n is the carbon number of the hydrophobic chain) was synthesized from cyanuric chloride, aliphatic amine, ethylenediamine, N, N'-dimethyl-1,3-propyldiamine and sodium 2-chloroethanesulfonate. The chemical structures of the prepared compounds were confirmed by FT-IR and H-1 NMR. The critical micelle concentrations (CMC) in aqueous solutions at 25 degrees C were determined by surface tension method. The CMC value decreased with increasing length of the carbon chain. The CMC reached a minimum as low as 5 x 10(-5) mol . L-1 for C-16-GSBS. The interfacial tensions (IFT) between Daqing crude oil and C-n-GSBS surfactant solutions were also measured. The effects of the concentration of Na2CO3, the concentration and carbon chain length of C-n-GSBS on the IFT of crude oil-water were investigated in detail. The results show that, for the aqueous surfactant system containing the weak base Na2CO3, oil-water interfacial tension can be reduced to 10(-2) mN m(-1) orders of magnitude. The results also indicate that with the increase of surfactant concentration and the chain length, the oil-water interfacial tension decreased markedly, which indicates that C-n-GSBS surfactants have a good interface activity. These surfactants are good candidates for weak base-surfactant-polymer EOR process.