CO2-responsive switchable hydrophilic solvent as a novel extractant for selective extraction and separation of natural bioactive ingredients: A comprehensive review.

When conventional solvents such as water, methanol, ethanol, hexane, petroleum ether, etc., are used to extract active ingredients from natural resources, an evaporation process is required to remove solvent from active ingredients, which not only consumes huge amounts of energy, but also causes harm to human health and the environment. The CO 2 -responsive switchable hydrophilic solvent (SHS) based on amines and water is an emerging, green and recyclable solvent, which not only has high extraction efficiency of active ingredients, but also can remove solvent from active ingredients without evaporation process. This paper reviews the research progress of amine-based SHS in the extraction of bioactive ingredients from natural resources. The process flow, extraction mechanism, critical influencing factors, recovery of amines and latest applications have been summarized. On this basis, some shortcomings of amine-based SHS are also pointed out. Finally, the improvement directions of amine-based SHS extraction in the future is prospected. • Amine-based SHS is a feasible alternative to traditional organic solvents. • The amine-based SHS extraction of active ingredients was comprehensively reviewed. • The mechanism, key factors, solvent recovery and latest applications were summarized. • The advantages, limitations, and future development directions were also discussed. • The amine-based SHS extraction has great potential in recovering bioactive ingredients. [ABSTRACT FROM AUTHOR]