Effect of alcohols on micelle formation in aqueous solutions of ethoxylated nonyl-phenols.

The micelle formation of ethoxylated nonyl-phenols in the presence of short-chain alcohols was investigated within a temperature range of 293-333 K. On the basis of the actual CMC values and their temperature dependence the thermodynamic functions of micelle formation (ΔHm0, ΔSm0, ΔGm0) and the thermodynamic functions of transfer of surfactant from pure aqueous phase to water-alcohol mixtures (ΔHtr0, ΔStr0, ΔGtr0) were also calculated. According to the experimental results the set of optimum conditions leading to the formation of a micellar structure with satisfactory stability can be determined. In the three-component systems the more stable the structure of micelles formed, the higher the temperature, the longer the alcohol chain length, the lower the alcohol content, and the shorter the poly-oxyethylene chain of monomers. With respect to the practical EOR process, it may be stated that the addition of alcohols to the solutions of short-chain nonyl-phenols makes it possible to extend their application to hydrocarbon reservoirs having high formation temperature. [ABSTRACT FROM AUTHOR]