T8 PM Measurement/ Estimation of Environmentally Relevant Physico-Chemical Properties
Tuesday, 15 November 2005: 1:50 PM - 5:30 PM in 337-338

(LIU-1117-821025) Determining Aqueous Solubility of Fluorotelomer Alcohols Using the Log-linear Cosolvency Model.

Liu, J¹, Lee, L¹, ¹ Agronomy Department, Purdue University, West Lafayette, IN, USA

ABSTRACT- Fluorotelomer alcohols, characterized by 4 to 14 even numbered perfluorinated carbon atoms attached to a -CH₂CH₂OH group, are a key class of compounds in understanding the global contamination of alkyl polyfluorinated compounds. However, the high level of perfluorination imparts to this group of compounds strikingly different properties than observed for its hydrogen and halogen analogues. Therefore, experimentally determined values of polyfluorinated compound properties such as solubility are needed to improve the predictive capability of current Quantitative Structure Activity Relationships (QSARs) and environmental fate and effects models. Accurate measurement of aqueous solubility of polyfluorinated compounds is greatly limited by their low solubilities, high volatility, sorption affinity for glassware and fluoropolymeric materials, thus a cosolvency approach was employed in this study to reduce possible bias of direct aqueous measurement. The log-linear cosolvency model assumes a log-linear relationship between solubility and volume fraction cosolvent (f_c) allowing estimation of aqueous solubility by extrapolation. Solubilities of 6:2, 8:2, and 10:2 fluorotelomer alcohols, the major components in commercial telomer alcohol mixtures, were determined directly in aqueous solution at 22°C and estimated by extrapolation from data measured in acetone/water and methanol/water solutions. LC-ESI-MS/MS was employed to directly analyze the fluorotelomer alcohols in aqueous and cosolvent solutions without a pre-concentration step. For the 8:2 fluorotelomer alcohol, aqueous solubilities of 0.194 mg/L and 0.224 mg/L were estimated by direct measurement and the log-linear cosolvency approach, respectively. Solubility data for the 6:2 and 10:2 fluorotelomer alcohols are currently being collected. Solubilities for the three alcohols will be correlated with each other and compared to literatures values for alky hydrocarbon alcohols using a QSAR approach.

Key words: Fluorotelomer alcohols, Aqueous solubility, Cosolvency