Computer Simulation Of The Solvation Properties Of Organic Species In Supercritical Water

Supercritical water(SCW) is a compressed liquid for which the temperature is higher than 647 K, and pressure is greater than 218 bar. In the supercritical state, the polarity of water can be changed by the pressure and temperature, so it can dissolve electrolytes and organic species simultaneously. As an organic solvent, supercritical water is not polluting, so making it suitable for green chemistry. SCW requires relatively harsh conditions to do experiments such as studying the solvation properties of organic substances in supercritical water, so using computer simulation to study the solvation properties of supercritical water is very beneficial.In this paper, two representative types of organic species, namely polar and non-polar organics, have been selected to study the solvation properties of supercritical water. The paper contains two main parts, the first part is studying solvation properties of the non-polar organics- CH4 and benzene – in SCW through MD simulation; the second part is studying solvation properties of polar organics – CH3 Cl and CH3 OH – in SCW through MD simulation.The solvation properties of supercritical water are investigated from four different aspects. First is to calculate the solvation free energy in different temperature through Bennett acceptance ratio method. Second, the energy of solution system is obtained from enthalpy. Third, the organic aqueous solution structure at different temperatures is obtained through the radial distribution function. Finally, to represent the solvation structure of organic molecules and water molecule through their angular distribution. For the study of the radial distribution function and angular distribution, selecting three representative temperature values, respectively is room temperature, the supercritical temperature and greater than the supercritical temperature.