Study On Synthesis And Properties Of Sulfonate Gemini Surfactants

Gemini surfactants exhibit lower CMC value and higher surface activity, which make them have a good prospect in EOR area. In this paper, eight sulfonate Gemini surfactants were synthesized from linear and branched alkylphenol respectively through dimmer ether reaction, sulfonation reaction and neutralization reaction. Through the means of single factor and orthogonal analysis, the influence of reaction time, reaction temperature, mixture ratio, sodium hydroxide dosage and catalyst on the rate of production was studied, and the methods of synthesis were optimized. Active matter content in Gemini surfactants was measured by two-phase titration method, indicating the high-purity; The structure of Gemini surfactants was confirmed by IR spectrum, 1H-NMR, MS and elementary analysis; The critical surface tension and critical micelle concentration were confirmed through the ring method and conductivity method, showing that CMC of the synthesized Gemini surfactants was 1-2 orders of magnitude lower than those of conventional surfactants; properties were compared to research the influence of hydrophobic groups and spacer groups. Thermal stability study showed that the initial decomposition temperature can reach 300℃. Effects of pH, temperature, salt content, as well as polymer to surface activity were researched and results show that synthesized surfactants have good chemical stability, temperature and salt tolerance. While polymer had little influence; Static absorption experiment on sand indicates saturated adsorptive capacity was about 3.5-4mg/g; Emulsifying capability of Gemini surfactants to a certain organic phase first increased then decreased with increasing spacer length. But to different organic phases, the longer carbon chain, the better emulsifying capability; Synthesized Gemini surfactants have excellent foam property. Foaming volume decreased and half period first increased then decreased on increasing spacer length; Foam property of combined system with AOS and OP-10 demonstrate that Gemini surfactants have good synergistic effect; The capability of Gemini surfactants to reduce the interfacial tension of Liao He crude oil have been measured, showing a good interfacial property and influence of structure to interfacial property was discussed; Laboratory displacement result indicated that Gemini surfactants could raise recovery by 15% based on water flooding.