Next Article in Journal
Miniaturized Matrix Solid-Phase Dispersion for the Analysis of Ultraviolet Filters and Other Cosmetic Ingredients in Personal Care Products
Previous Article in Journal
Balancing Resolution with Analysis Time for Biodiesel–Diesel Fuel Separations Using GC, PCA, and the Mahalanobis Distance
Open AccessArticle

Recycling of 1,2-Dimethyl-3-propylimidazolium bis(trifluoromethylsulfonyl)imide Ionic Liquid by Stacked Cation and Anion Exchange Adsorption-Desorption

Laboratories for Advanced Materials, Department of Chemistry & Chemistry Research Center, United States Air Force Academy, Colorado Springs, CO 80840, USA
*
Author to whom correspondence should be addressed.
Separations 2019, 6(2), 29; https://doi.org/10.3390/separations6020029
Received: 22 April 2019 / Revised: 14 May 2019 / Accepted: 27 May 2019 / Published: 3 June 2019
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%. View Full-Text
Keywords: ionic liquid; recycling; ion exchange; adsorption-desorption; [DMPIm][NTf2] ionic liquid; recycling; ion exchange; adsorption-desorption; [DMPIm][NTf2]
Show Figures

Graphical abstract

MDPI and ACS Style

Corley, C.A.; Iacono, S.T. Recycling of 1,2-Dimethyl-3-propylimidazolium bis(trifluoromethylsulfonyl)imide Ionic Liquid by Stacked Cation and Anion Exchange Adsorption-Desorption. Separations 2019, 6, 29.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop