Prediction of phase equilibria and Gibbs free energies of transfer using molecular exchange Monte Carlo in the Gibbs ensemble

• Published in: Fluid phase equilibria Vol. 486; pp. 106 - 118
• Main Authors: Soroush Barhaghi, Mohammad, Potoff, Jeffrey J.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-05-2019
• ISSN: 0378-3812; 1879-0224
• DOI: 10.1016/j.fluid.2018.12.032

The molecular exchange Monte Carlo (MEMC) method is extended to Gibbs ensemble Monte Carlo (GEMC). The utility of the MEMC method is demonstrated through the calculation of the free energies of transfer of n-alkanes from vapor into liquid 1-octanol, n-hexadecane, and 2,2,4-trimethylpentane using isobaric-isothermal GEMC simulations. Calculations are performed for both the Transferable Potentials for Phase Equilibria (TraPPE) and Mie potentials. For all solutes, the Mie potentials predict free energies of transfer that are within 0.1 kcal/mol of experiment for solvation in n-hexadecane and 2,2,4-trimethylpentane. For TraPPE, solutes shorter than n-butane show similar agreement with experiment, but free energies for n-octane in n-hexadencane and 2,2,4-trimethylpentane are over-predicted by approximately 0.25 and 0.5 kcal/mol, respectively.