Molecular dynamics simulation and experiment measurement of infinite dilute diffusion coefficients of methanol and ethanol in supercritical CO2

A new approach to represent the infinite dilute diffusion coefficients of organic compounds in supercritical carbon dioxide was proposed. The infinite dilute diffusion coefficients of methanol and ethanol in supercritical CO2 were investigated by molecular dynamics (MD) simulation. In order to compare the simulation results, according to Taylor dispersion principles, the infinite dilute coefficients of methanol and ethanol were determined by Supercritical Chromatography. As Taylor dispersion method was easily to reach to supercritical condition, it was suit for the calculation of supercritical diffusion coefficients. In this work, the results of the MD simulation of the infinite dilute diffusion coefficients of methanol and ethanol behaved good accordance with the experiment and literature data. This new method can be used to predict the diffusion property of supercritical systems effectively and be employed for engineering design conveniently. Therefore, as an advanced research means, molecular dynamics simulation will be used more widely.