John Wiley & Sons, Ltd.

Evaluation of the three‐phase equilibrium method for measuring temperature dependence of internally consistent partition coefficients (KOW, KOA and KAW) for volatile methylsiloxanes and trimethylsilanol

0
- By: ,

Courtesy of John Wiley & Sons, Ltd.

Partitioning equilibria and their temperature dependence of chemicals between different environmental media are important in determining the fate, transport, and distribution of the contaminants. Unfortunately, internally consistent air/water (KAW), 1‐octanol/air (KOA), 1‐octanol/water partition coefficients (KOW), and the information of their temperature dependence, are scarce for organosilicon compounds due to the reactivity of those compounds in water and/or octanol and their extreme partition coefficients. In this study, the newly published 3‐phase equilibrium method was evaluated for simultaneous determination the temperature dependence of KAW, KOA, and KOW of five volatile methylsiloxanes (VMS) and trimethylsilanol (TMS) in the temperature range from 4 °C to 35 °C. The measured partition coefficients at the different temperatures for any given compound, and the enthalpy and entropy for the corresponding partition processes were all internally consistent, suggesting the 3‐phase equilibrium method is suitable for this type of measurement. Compared to common environmental contaminants reported in the literature, VMS have enthalpy and entropy relationships similar to those of alkanes for air/water partitioning, similar to those of polyfluorinated compounds for octanol/air partitioning, but more like those for benzoates and phenolic compounds for octanol/water partitioning. The temperature dependence of the partition coefficients of TMS is different from those of VMS and is more like that of alcohols, phenols and sulfonamides. Environ Toxicol Chem © 2014 SETAC

Customer comments

No comments were found for Evaluation of the three‐phase equilibrium method for measuring temperature dependence of internally consistent partition coefficients (KOW, KOA and KAW) for volatile methylsiloxanes and trimethylsilanol. Be the first to comment!