Study On The Synthesis And Properties Of Alkyl Dimethylphenyl Sulfonates

By means of molecular designing, we synthesized three kinds of alkyl dimethylphenyl sulfonate surfactants. With dimethylbenzenes(o-,m-,p-xylene,) and α-olefin(C20-24) as raw material, by Friedel-Crafts alkylation reaction, sulfonation reaction and neutralization reaction, using ionic liquid as catalyst has strong activity,finally they synthesized series of sulfonate surfactants. And the content of surfactant in the products were all over 95% determined by two-phase titration. In the Friedel-Crafts alkylation reaction, the effect of the ratio of aromatics and olefins, the quality of olefins and catalysts, reaction time and reaction temperature on the yield of alkyl dimethylphenyl was examined by orthogonal experiments. In the optimum conditions: n(aromatics):n(olefins)=5:1,m(olefins) :m(catalysts)=30:1,the reaction time was 1h and the reaction temperature was 30℃. Under which the yield of long chain alkyl aryl was 85%~90%. The structures of sulfonates were proved to be correct by FT-IR.The surface tension of the kinds of surfactants were measured at different concentrations as well as at different temperatures by using drop-volume method. The relationship between surface tension and concentration and temperature were also obtained. At a given temperature, with the increasing of the concentration of surfactants, the critical micelle concentration(cmc) decreased and the surface tension at cmc(γcmc) reduced. At a given concentration, with the temperature rises, the cmc increased and the γcmc. decreased.The interfacial behavior relationships between alkyl dimethylphenyl sulfonate surfactants and the crude oil of 2nd plant of Daqing oilfield were measured by the Model 500 spinning drop interfacial tension meter. Then the impacts of the concentration of the sulfonates, the concentration of base,the concentration of salt and short chain alcohol on the dynamic interfacial tension were respectively discussed. In the appropriate base concentration and salt concentration, the results showed that all the interfacial tension between the kinds of alkyl dimethylphenyl sulfonate and the crude oil of 2nd plant of Daqing oilfield could reach ultra-low interfacial tension(10-3mN/m). the interfacial tension was decreased to ultra-low value with the short chain alcohol added, enhanced oil recovery greatly.The emulsification properties of alkyl dimethylphenyl sulfonate surfactants were studied by the meaning of water separation. With the increasing of the concentration of surfactants, the degree of branching became harder, the longer the time of emulsion, the better stability of emulsion formation. As the temperature increased,the emulsifying ability of surfactants decreased gradually.