Prediction of the temperature dependency of Henry's law constant using poly-parameter linear free energy relationships.

The ability to predict the temperature dependence of air/water partitioning is important for the environmental fate modeling of organic pollutants. Here, literature data for the temperature dependence of air/water partitioning of some 200 compounds have been used to derive poly-parameter linear free energy relationships (pp-LFER) for predicting air/water partition coefficients at temperatures between 0 and 45 degrees C. The compounds used for calibrating the pp-LFERs span a range of almost 10 orders of magnitude in the partition constants and they cover a large variety of functional groups. Very good fits (r(2)>0.99) were obtained at all temperatures. Hence, these pp-LFERs should serve as a valuable tool for integrating the temperature dependence of air/water partitioning into fate modeling of organic compounds. In the environment one will quite often encounter a situation where water and air do not have the same temperatures. This situation is shortly discussed in the appendix.