Determination of Henry's law constants through transition matrix Monte Carlo simulation

We present results for the Henry's law constant of methane, oxygen, nitrogen, and carbon dioxide in saturated liquid ethanol at temperatures of 323 and 373 K. Monte Carlo simulations are conducted in an expanded isothermal-isobaric ensemble in which the interactions between a solute particle and the solvent are gradually increased over a series of steps. A self-adaptive transition matrix Monte Carlo method is used to determine infinite-dilution excess chemical potential values for the solute. The TraPPE force field is used to describe molecular interactions. Henry's law constants follow the trend: nitrogen > oxygen > methane > carbon dioxide. Agreement between modeling and experimental values is reasonable. (c) 2005 Elsevier B.V. All rights reserved.