Measurement of Enthalpy and Free Energy Changes for Dissolution in Concentrated Electrolyte Media Using Molecular Simulations

Although enthalpies of mixing are straightforward to calculate using molecular simulations when the individual components are both pure liquids, substantial difficulties arise when one of the components is already itself a concentrated electrolytic medium, and for the dissolution of solids in liquids. Further complications arise when entropies must be calculated to determine free energies of mixing. Using a combination of theoretical and modeling results, we show how molecular dynamics can be used to estimate the mixing properties and energies of such thermodynamic systems, using dissolution of cellulose as a test case for demonstrating the effectiveness of the method. Comparison to experimental results show good agreement as a function of solution composition.