MOLECULAR THERMODYNAMICS IN THE DESIGN OF SUBSTITUTE SOLVENTS

The use of physical properties and fluid behavior from molecular therm odynamics can lead to better decision making in the design of substitu te solvents and can greatly reduce the expense and time required to fi nd substitutes compared to designing substitute solvents by experiment , This paper systematically discusses the equilibrium and dynamic prop erties and the fluid behavior which are important for designing substi tute solvents. For each property, it discusses the rationale for using the property, the current level of understanding from molecular therm odynamics, the general methodology for estimating the property for sin gle chemicals, and suggested methods for liquid mixtures. In addition to bulk physical solvent properties such as viscosity, other solution properties such as activity coefficients are also important for design ing substitute solvents. The use of limiting or infinite dilution acti vity coefficients in the context of substitute solvent design is discu ssed. Lastly, other requirements such as solvent safety properties inc luding flash point and solvent phase and chemical stability are fully discussed.