A switchable-hydrophilicity solvent (SHS) is a solvent that in one state forms a biphasic mixture with water but can be reversibly switched to another state that is miscible with water. All of the amine SHSs that we have reported previously lie within a particular basicity and hydrophilicity range (9.5 < pKaH < 11 and 1.0 < log Kow < 2.5, respectively). We report an extension of this range by altering the pressure of CO2 as well as the water : SHS volume ratio used in the process. Increasing the pressure of CO2 and/or the water : amine volume ratio allows some amines with pKaH < 9.5 or log Kow > 2.5 to function as SHSs.

A virtual or in-silico screening approach makes it much easier to identify the molecular structure that best combines efficacy for a specific task with safety and minimum environmental or health impacts. In this approach, software is used to generate a larger number of possible molecular structures and then to use QSARs (quantitative structure-activity relationships) to predict properties related to performance, safety, and health and environmental impact. The structures are are then given scores on criteria (such as flash point or toxicity) and an overall score. The method identifies compounds that have high scores for the 3 performance criteria and 7 health, safety, and environmental criteria. This method allows for larger-scale and faster screening than can be performed using human intellect and a benchtop approach. The success of this approach is demonstrated by its application to the identification of new and possibly greener switchable-hydrophilicity solvents (SHS). Three SHS were identified using this method. This approach to molecular design is entirely modular and can be applied to the design of almost any type of chemical. However, limitations of the method include the fact that it does not take into consideration the health and environmental costs of manufacturing the chemical.

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