Study On Synthesis Of Sulfo-betaine Surfactants And Surface Activities Of Their Combined System

Betaine type surfactant is a zwitterionic surfactant with unique properties. Thetwo type’s sulfo-betaine surfactants were synthesized in this study. With orthogonalexperiments, the influence factors of the quaternization such as reaction temperature,reaction time, the mole ratio of the feed and so on were investigated systematicallyand the optimum conditions for reaction were obtained. Following as:1) the moleratio of the tertiary amine/intermediate (I)(3-Chloro-2-Hydroxy Propanesulfonate)=1.0:1.3, mixed solvent (isopropanol and water,1:2,v/v) as reaction medium, reactedfor6hours at80oC for synthesis of SB;2) mixed solvent (isopropane/water=1:2,v/v)as reaction medium, NaOH(37.5mmol) as catalyst and reacted at90oC for24hoursfor preparing of ASB. The crude samoples obtained were purified by crystalline withabsolute ethanol and characterized by IR spetrum and elemental analysis. As theresults showed that the structures of the products obtained from the experimentsnearly are identical with the design target molecular.The products (SB and ASB) were combined with AES and LAS commonsurfactant products and the theoretic calculationof compounded systems have beendone according to the regular solution theory and Gibbs Formulae of monolayeradsorption. The interaction parameters () of the surface adsorption layer and themixed micelles were obtainedrespectively, quantitatively indicating the the synergeticeffect of compounded systems. The SB-12/AES compounded system has the biggestsynergetic effect.Some surface activities were explored. For these binary systems, thesurfacetension, interface tensions between the crude oil and aqueous solution of themix surfactants and the foaming property were determined, while some influencefactors such as the concentration of the salt, mineral materials and temperature etcwere studied. As the results show, the interfacial tension between the crude oil andmixed surfactant solutions were dropped down to10-3mN/m magnitude, especially isreached8.5×10-3mN/m for SB-16/LAS combined system (mass ratio of4:6). It fully achieves the standard of the enhancing oil recovery. Furthermore，the foamingproperties of the some mixtures are prior to that of single surfactant aqueous solutionaccording to measurements, its initial volume of the bubbles is600mL and the thefoaming half-life is reaced to80mins and more, that lays the foundation for furtherformulation of the oil displacement agent.