Molecular Dynamics Simulations for Systematic Prediction of the CO₂ Solubility of Physical Absorbents

抄録

A simple theoretical methodology to predict the CO₂ solubilities of physical absorbents is proposed based on free energy calculations using molecular dynamics simulations. Here, the free energy profiles were estimated for a CO₂ molecule approaching several types of solvent molecules: polyethylene glycol (PEG), polyethylene glycol dimethyl ether, tetraglyme, glycerol, glycerol carbonate, and methanol. Remarkable differences were observed between the minimum values of the free energy profiles for the seven solvents. The energetic minima of the PEGs were deeper and wider than those of the other solvents, demonstrating that PEG solvents have higher affinity for CO₂. It was also suggested that the simulated minimum values for these profiles are correlated with the experimental CO₂ absorbed amounts. The refinement of our simple approach can contribute to the efficient screening of possible physical absorbents for carbon capture and storage.