Study On The Synthesis Of Sodium 2-hydroxy-3, 5-alkylbenzenesulfonates And Their Physicochemical Properties

The molecular design of the oil-displacing surfactants is the researchful leading edge in the field of enhanced oil recovery, and its pivotal question is the relation between the molecular structures of the surfactants and their properties. The in-depth studies on this question can provide the academic foundation for the exploitation of new type, high performance oil-displacing surfactants.In the dissertation, novel nine sodium 2-hydroxy-3,5-alkylbenzenesulfonates, with hydroxyl substituent, were synthesized through several processes including Friedel-Crafts acylation, esterification, Fries rearrangement, Pd-catalyzed hydrogenation, sulfonation and neutralization. The chemical structures were characterized by 1H NMR, IR and MS methods. The contents of sodium 2-hydroxy-3,5-alkylbenzenesulfonates in the products, determined by two-phase titration, were all above 99%.The effects of hydrophobic structure and hydroxyl substituent of sodium 2-hydroxy-3,5-alkylbenzenesulfonates on interfacial properties were more systematically investigated. The surface tensions of sodium 2-hydroxy-3,5-alkylben- zenesulfonates were investigated in aqueous solution and in NaCl solutions, and the interfacial tension between sodium 2-hydroxy-3,5-alkylbenzenesulfonates in NaCl solutions and hendecane. The values of cmc,γcmc, pC20,Γm ax, were obtained by the 0ΔGadγ- curves. It was discovered that the hydrophobic structure and hydroxyl substituent of sodium 2-hydroxy-3,5-alkylbenzenesulfonates influence profoundly on the adsorption and interfacial tension. For the first time, the effects of particular cross-sectional area (algCs) and interaction among hydrophobic alkyl chains (BBss) of sodium 2-hydroxy-3,5-alkylbenzenesulfonates on adsorption and interfacial tension were explained on the basis of the two-dimensional gas model of Blankschtein.Dynamic surface tension of sodium 2-hydroxy-3,5-alkylbenzenesulfonates was investigated in aqueous solution. Dynamic surface parameter and effective diffusion coefficient Deff were obtained by use of Rosen equation and Word-Tordai equation.The dilational viscoelastic properties of sodium 2-hydroxy-3,5-alkylben- zenesulfonates at water-air and water-decane interfaces were investigated by means of Langmuir trough or oscillating bubble/drop method. The dynamic dilational properties and the dependences of interfacial dilational modulus, phase angle, elasticity and viscosity on the concentrations and the frequencies were explored using both methods: the interfacial tension response to sinusoidal area variations and the relaxation of an applied stress. The result showed that the distinct maxima appeared in dilational modulus vs time curve, which was different from the conventional alkylbenzene sulfonates and was believed to be attributed to the hydrogen bond interaction between surfactant molecules and water molecules at the interface, the change of surfactant conformation, and the arrangement of surface layer.The foam properties of sodium 2-hydroxy-3,5-alkylbenzenesulfonates in the aqueous solution were measured by air flowing method. It was shown that the foaming ability decreased as the carbon number of hydrophobic alkyl chain increasing, while the foaming stability increased, then decreased.The micelle formation of sodium 2-hydroxy-3,5-alkylbenzenesulfonates was investigated by Fluorescence technique. The result we obtained showed that micelle aggregation number varied as the carbon number of hydrophobic alkyl chain changed.