Preparation And Properties Of Carboxylate Gemini Surfactant

Exploiting the crude oil economically and effectively have been to the goal that researcher strive for. EOR research and development process shows:polymer-surfactant fiooding has a very broad application prospects. But in present oil fields, the surfactants applies in polymer-surfactant flooding are petroleum sulfonate surfactants, which have poor abilities in reducing the interfacial tension. Besides, the consumption of these surfactants is large and matching performance is poor. The goal of this paper is to develop a series of excellent performance and good compatibility carboxylate Gemini surfactant to meet the needs polymer-surfactant flooding.In this paper, the Gemini surfactant R-GS was designed and synthesized. Then the surfactant was characterized by IR,1HNMR and MS, which identified the correspondence of the designe. The synthesis conditions of TE monomer and R-GS surfactants were optimized by orthogonal experiments.Through the conductivity measurements, the Krafft points of R-GS surfactants were determined and the the Krafft points were increased with the increasing hydrophobic chain length of the surfactant.Besides, cmc and ycmc of R-GS surfactants were also determined. It found that the Gemini surfactants have much higher surface activities comparing with sodium laurate, sodium palmitate, sodium myristate.Through the study of apparent viscosities of the polymer/surfactant system, it found that the mixture of hydrophobic associating polymer AP-P4and R-GS surfactant can significantly increase the apparent viscosities of the solution to some extent, and the highest point of the apparent viscosities of the surfactant concentration followed by18-GS、12-GS、14-GS、16-GS.Through the stress sweeping measurements of the polymer/surfactant system, the mixture solutions of polymer AP-P4and R-GS surfactant can form a stronger networK structure to some extent. The effects of R-GS surfactant on polymer/surfactant system on linear viscoelastic region were followed by16-GS、14-GS、12-GS、18-GS、the elastic modulus of mixture solution can reache a maximum at the14-GS surfactant concentration of30mg/L. Elevationg the14-GS surfactant concentration, the elastic modulus and the viscous modulus of the mixtured solution were decreased. When the surfactant concentration was above100mg/L, the viscous modulus posts a dominant position, which indicates that the polymer/surfactant system was transformed from the sol state into the gel state with the increasing concentrations of14-GS surfactant. By fluorescence probe measurements to study the interaction of14-GS surfactants with polymer AP-P4, it found that the formation of hydrophobic microdomain was promoted with the addition of surfactant in the initial stage, so the I3/I1values were increased. With the further addition of surfactant, the hydrophobic domains formed in solution has been able to solubilize the most of the pyrene probe. And the I3/I1values of polymer/surfactant system remained unchanged.When studying the relationship between the hydrodynamic radius<Rh> of the mixture solutions and the concentrations of14-GS surfactant, it found that the hydrodynamic radius <Rh> were firstly increased and then decreased with the increment of surfactant concentration and the a maximum particle size was at the14-GS surfactant concentration of30mg/L, which was equal to the results of apparent viscosities of mixture solutions.