Effect of cosurfactant on water solubilization in supercritical carbon dioxide microemulsions

Abstract

Water solubilization in supercritical carbon dioxide (SC CO 2) microemulsions prepared using F-AOT (fluorinated-sodium bis (2-ethylhexyl) sulfosuccinate) analogues has been compared in the presence of cosurfactant n-butanol. At pressure 44 MPa and 35 °C, the addition of n-butanol to di-HCF4 (sodium bis(1 H,1 H,5 H, octafluoropentyl) sulfosuccinate)/SC CO 2 microemulsion enhanced the water solubilization from W 0 = 30 to 45. Increasing the amount of cosurfactant further enhanced the water solubilization. At R = 10, a maximum amount of water W 0 = 49 was dissolved in di-HCF4/SC CO 2 system which is highest reported so far in SC CO 2 microemulsions. W 0 and R represent the molar ratio of water- and n-butanol-to-surfactant, respectively. F-AOT/SC CO 2 microemulsions were characterized by pressure dependent water solubilization phase diagram and high pressure UV absorption spectroscopy.