Modeling the temperature dependence of the Henry's law constant of organic solutes in water

The Henry's law constant of a chemical solute in water exhibits a maximum value at a temperature that is characteristic of the solute. Understanding how to better correlate Henry's law constant data versus temperature can contribute to improved designs of water treatment equipment. To address this data need, two chemical structure-based models have been developed to correlate an organic chemical's Henry's law constant over a wide temperature range, i.e., from ambient conditions to temperatures in excess of 100 °C. The two models combine fundamental solution thermodynamics principles with additive bond and group contributions. A literature database of over 750 critically evaluated data points, covering six orders of magnitude in volatility, has been assembled to develop the calculation methods. The two models, which are simple to apply, correlate the aqueous Henry's law constant as a function of temperature for alkanes, cycloalkanes, alkenes, cycloalkenes, benzene, alkylbenzenes, primary and secondary alcohols, aliphatic chlorides, and ketones.