Soybean oil extraction and separation using switchable or expanded solvents

The extraction of soy oil from soybean flakes in industry requires large amounts of hexane solvent and results in significant losses and energy consumption during the distillative removal of the solvent. Hexanes and related hydrocarbon extractants are also becoming an environmental and health concern. A new method for extraction of the oil is sought, that would require neither hexane nor distillative removal of solvent. This article presents a preliminary assessment of several new methods for soy oil extraction and subsequent solvent removal from the oil. The most promising are (a) extraction by an amidine switchable solvent that can then be removed from the soy oil by carbonated water and (b) extraction by a moderately hydrophilic solvent that can then be removed from the oil by water.