A Mini-Review on Greenness of Ionic Liquids

Ionic liquids (ILs) have been considered as "green solvents" in many published works. However, recent research on their eco-toxicity and degradability has proven that some ILs are not as "green" as expected. In this review, the greenness of ILs was discussed in terms of their synthesis, eco-toxicity and degradability and their applications. Greenness of ILs depends not only on themselves but also on their synthesis and specific applications. For a chemical process where the IL is employed, its greenness should be assessed using the life cycle analysis method and compared with other alternative processes. The green process is much more important than the IL itself with respect to green chemistry, and more research should be made to improve the greenness of process employing ILs.