Use of inherent SHS switchability for purification

Abstract

Alternative solvents based on switchable hydrophilicity solvents is an exciting and interesting new field in chemistry, specifically for green chemistry. Many amines represent potential non-volatile organic solvents that could replace many of the more dangerous and environmentally problematic solvents currently used in industry. The primary challenge with many alternative non-volatile solvents, is the inability to recover the solvent from the system. However, switchable hydrophilicity solvents (SHS) solve this because they can switch reversibly between one form that is biphasic with water, to another that is monophasic after the addition of carbon dioxide. Methods to produce amines often end with a variety of side reactions, unreacted starting materials, and other unwanted compounds. This work looks at the ability to produce the “dirty’ amines of interest, then using the inherent switchability of the solvents to extract the solvents from the typical waste that results from the production. Meaning that when you have a mixture of a switchable solvent and the non-switchable waste, the addition of water will initially form biphasic layers. However, after the addition of CO2 into the system, the switchable solvent will be extracted into a monophasic mixture with water, leaving behind the waste. After removal of the water-solvent mix, and subsequent switching off of the system by the removal of CO2 , the cleaned up solvent can be recovered. This is an innovative approach to the purification of these products that can result in more environmentally friendly methodologies.

Faculty Mentor: Roland Lee

Department: Chemistry