Abstract
There are many advantages to using ionic liquids as solvents or catalysts in chemical processes. Their non-volatile characteristic and high cost, however, can pose economic, environmental, and long-term health concerns. As such, the recovery and recycling of ionic liquids have become essential to mitigate their environmental impact and to reduce costs. Numerous recovery and recycling methods have been reported, including distillation, extraction, membrane separation (a.k.a. filtration), adsorption, crystallization, gravity, and electrochemical separation. Whereas most of these methods recover both cations and anions of the ionic liquid as ion pairs, recycling methods such as single-phase ion exchange or mixed-ion exchange/non-ionic adsorption methods recover only one of the ionic liquid ions, typically the cation. These methods are frequently used for the recycling of ionic liquids having simple anions such as chloride or acetate, but are seldom employed for ionic liquids consisting of larger and more complex anions due to the added time and reagent costs necessary for the regeneration of the original ionic liquid. Herein, a combined cation and anion exchange adsorption-desorption method is presented that can effectively separate 1,2-dimethyl-3-propylimidazolium bis(trifluoromethylsulfonimide) [DMPIm][NTf2] ionic liquid from neutral impurities. More importantly, the method is capable of recovery and recycling of the original ionic liquid. Concomitant desorption of both ionic liquid ions was achieved using 0.1 M NaCl: methanol (90:10 v/v) eluent followed by isolation using liquid–liquid extraction to afford high purity products and yields of approximately 60%.
Highlights
Ionic liquids are high molecular weight salts that are liquid at room temperature and typically liquid over a very broad temperature range
The first room temperature ionic liquid, [EtNH3 ][NO3 ], was introduced in 1914 [1] but notable interest did not arise until the discovery of binary ionic liquids made from aluminum (III) chloride
A thorough study was performed consisting of a series of experiments aimed at finding optimal conditions for the desorption of [DMPIm][NTf2 ]
Summary
Ionic liquids are high molecular weight salts that are liquid at room temperature and typically liquid over a very broad temperature range. The adsorption–desorption recycling method has Akin attracted much attention in the last two decades, sampleto preparation techniques [31], the method utilizes an adsorption-desorption based on owing its excellent selectivity, robust and simple operation, relatively low cost,strategy non-destructive differencesmechanism, in affinitiesand of ionic liquids andtoimpurities to aphase solidextraction surface (sorbent). Is attractions to ion exchange recycling methods is their ability to produce ionic liquids of highThis purity especially whenofworking withhowever, ionic liquids comprised of large or complex that and yields.problematic. Wide utilization this method, is hampered by the method’s inabilityanions to recover are oftentimes prepared from expensive precursors.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
