Predicting adsorption of n-perfluorohexane in BCR-704 by molecular simulation

The vapor pressure of n-perfluorohexane at 293 K was calculated using Gibbs Ensemble Monte Carlo simulation, and its adsorption isotherm in BCR-704 was estimated using Grand Canonical Monte Carlo simulation. The TraPPE force field was used with n-perfluorohexane modeled as united CF2 and CF3 atoms (pseudoatoms) with partial charges calculated using quantum chemistry. We found that the vapor pressure of pure n-perfluorohexane at 293 K to be 0.32 ± 0.06 bar, and that there are more than 16 n-perfluorohexane molecules/unit cell in BCR-704 at all the challenge pressures considered, pr = p/0.32 = 0.01, 0.05, 0.1, 0.2, 0.4, 0.6 and 0.8. The n-perfluorohexane adsorption sites in BCR-704 were found to be in the supercages and their connecting channels based on the density distribution of the adsorption sites that we found.