Solubility Measurements of Surfactants in 1,1,1,2-Tetrafluoroethane
學生：李介仁 指導教授：余 艇
中亦測量一些界面活性劑如 sodium bis-2-ethylhexyl sulfosuccinate ( AOT ), didodecyldimethylammonium
bromide (DDAB), n-dodecyltrimethylammonium chloride (DTAC) 及 cetyltrimethylammonium chloride
Solubility Measurements of Surfactants in 1,1,1,2-Tetrafluoroethane Student : Jie-Ren Li Advisor : Tiing Yu Department of Applied Chemistry, National Chiao Tung University Abstract Extraction of analytes from solid and liquid matrixes using supercritical or liquid carbon dioxide ( SFCO2 ) has been extensively studied in the past. Due to its non-polar property, only less polar components are soluble in carbon dioxide. However, hydrophilic species, such as proteins can be dissolved in carbon dioxide with certain florinated surfactants. Micelle formation was proved responsible for the solubilization. Carbon dioxide turns into gas after extraction that spares the endeavor of further concentrating the collected analytes. However, the operative pressures for maintaining adequate solvent strength for supercritical or liquid carbon dioxide can be well above 100 bar; this may depreciate the value for practical application. We replaced carbon dioxide with the ozone-depletion free refrigerant 1, 1, 1, 2-tetrafluoroethane (R134a) as the solvent in this study. Hydrophilic compounds, methyl orange and cytochrome c can be solubilized in liquid R134a in the presence of cationic surfactant trioctylmethylammonium chloride ( TOMAC ). Significant red shift of methyl orange in liquid R134a in the presence of TOMAC indicates micelles were formed in liquid R134a. We also measured the solubilities of some commercial surfactants such as, sodium bis-2-ethylhexyl sulfosuccinate ( AOT ),didodecyldimethyl- ammonium bromide ( DDAB ), n-dodecyltrimethylammonium chloride ( DTAC ) and cetyltrimethylammonium chloride (CTAC) in R134a. The measurements were performed in the pressure range from 15 to 100 bar at the temperature range from 15 to 350C. In addition to the effects of pressure and temperature, the influence of cosolvent will also be discussed. AOT shows better solubility in R134a than those of other surfactants. R134a also becomes gas after extraction and separates from the collected analytes; therefore possesses the same advantage like carbon dioxide. Since the operative pressure for R134a can be as low as 10 bar, it may prove to be more practical than using carbon dioxide as the extraction solvent. Accordingly, it may be applied to recover hydrophilic compounds of low concentration from aqueous solution in the presence of surfactant.
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