ie6b01074_si_001.pdf (589.87 kB)
Molecular Dynamics Simulation Study on CO2 Physical Absorption Mechanisms for Ethylene-Glycol-Based Solvents Using Free Energy Calculations
journal contribution
posted on 2016-07-05, 00:00 authored by Ryo Nagumo, Yukihiro Muraki, Shuichi Iwata, Hideki Mori, Hiromitsu Takaba, Hidetaka YamadaMolecular
mechanisms of CO2 physical absorption are
significant for the development of higher-performance CO2 absorbents. In this study, the free energy profiles for CO2 approaching several types of ethylene glycol (EG)-based solvent
molecules and their derivatives (diols, ethers, and alkanes, etc.)
were evaluated using molecular dynamics simulations. A desolvation
barrier appeared in the free energy profiles in the pure component
solvent, corroborating the negative contribution of a void effect
on CO2 affinities. The profiles in vacuum were also estimated
to investigate the functional group effects in a constituent solvent
molecule. The profiles for the EG-based solvent molecules showed similar
minimum values to their derivative diols, while the values for their
derivative ethers and alkanes were markedly higher. CO2 solubility is certainly determined by two major factors: the specific
CO2 affinities of the constituent hydroxyl groups and a
steric void effect near an absorbed CO2 molecule.