Syntheses and Properties of Methoxy and Nitrile Functionalized Imidazolium Tris(pentafluoroethyl)trifluorophosphate Ionic Liquids

Abstract

An alternative and more benign method was employed to synthesize tris(pentafluoroethyl)trifluorophosphate (FAP) ionic liquids (ILs). Ion exchange chromatography was used instead of the typical electrochemical fluorination developed by Ignat'ev and co-workers. The resulting procedure is simple and can be readily performed, as the use of corrosive hydrofluoric acid and the production of toxic and explosive byproducts were circumvented. Functionalization of the alkyl group of the imidazolium cation with a methoxy and a nitrile moiety was employed to observe changes in properties. The success of the synthesis was confirmed by 1 H, 19 F, and 31 P NMR, IR, and UV−vis spectroscopy techniques. Quantitative product yields of approximately 80% (w/w) were obtained. The water content and viscosity values of the synthesized FAP-based ILs were found to be lower compared to other fluorinecontaining ionic liquids. Thermal analyses resulted in high thermal degradation temperatures greater than 573.15 K. Electrochemical analyses showed potential windows of values greater than 5.0 V, indicating electrochemical stability. On the basis of the basic properties observed, the FAP-based ILs synthesized in this study may be useful as gas absorbents, electrolytes, and other applications, especially those involving extended temperature ranges.

Exploring the corrosion inhibition capability of FAP-based ionic liquids on stainless steel

“…Table 1 shows the FAP-based ionic liquids used in this study. The ionic liquids were prepared according to a previously reported method by our group [ 36 ]. The spectroscopic analyses, water content and chloride impurities of these ionic liquids were also presented in the same study, showing the purity of these samples.…”

“…In addition, these types are thermally and electrochemically stable, making them ideal for anti-corrosion application [34]. In fact, a previous study performed by our group was able to show that properties of FAP ionic liquids are comparable to that of the well-studied and well-performing Tf 2 N-based ionic liquids [36]. Moreover, these FAP ionic liquids were determined to possess even better electrochemical stability showing wider potential windows, keeping in mind of course counter cations and differences in electrodes used.…”