Thermally-Stable Imidazolium Dicationic Ionic Liquids with Pyridine Functional Groups

Abstract

Thermally-stable ionic liquids (ILs) have limited structural possibilities and lack coordinating anions or functional groups. Thermal stability effectively incurs a tunability penalty, limiting ionic liquid function to render them as simple heat-stable fluids. In this work, a series of new thermally-stable dicationic ionic liquids with pyridine functional groups, abbreviated [(C8ImC1)2Py]­[A]2, are presented and compared to nonfunctional geminal dicationic ILs. All ILs have been thermally characterized to understand their elevated temperature stabilities and the processes that lead to their decomposition. Importantly, functional [(C8ImC1)2Py]­[A]2 with noncoordinating anions (i.e., [NTf2]−) have thermal stabilities comparable to those of geminal dicationic ILs, with the added advantage of a functional pyridine moiety. Dissolution of Zn­[NTf2]2 in [(C8ImC1)2Py]­[NTf2]2 is demonstrated, and the resulting solutions are characterized to show their liquid properties, high thermal stabilities, and the coordination of the metal center to the functional group. This is the first example of a thermally-stable functional IL with the potential to reclaim the tunable, task-specific nature of ILs at elevated temperatures. Importantly, these properties open new avenues for high-temperature applications of IL by extending their operational ranges; catalysis, metal remediation, and separation-based applications are potential key areas of improvement.

Controlling surface chemistry and mechanical properties of metal ionogels through Lewis acidity and basicity

“…S46 †). 40 However, thermal stability of the [omim][NTf 2 ]-0.33 Zn[NTf 2 ] 2 ionogel with 30% PEGDA was signicantly compromised when compared to the Zn free ionogel analogue (T onset reduce by 173 C). Furthermore, reducing the quantity of Zn did not improve thermal stability, and even small quantities of Zn (i.e., c ¼ 0.05) signicantly impacted ionogel thermal stability (ESI, Fig.…”

Application of Ionic Liquids for Chemical Demulsification: A Review

“…Ionic liquids have been widely used in different fields like pharmaceutical, oil and gas, and chemical industries [ 53 , 54 , 55 , 56 , 57 , 58 ], such as in pharmaceutical products manufacturing [ 59 , 60 , 61 , 62 ], viscosity modifiers [ 63 ], desulfurization of liquid fuels [ 64 ], and liquid-liquid extraction [ 65 , 66 , 67 ]. Several types of ionic liquids, such as polymeric ionic liquids [ 68 , 69 , 70 ], double salt ionic liquids [ 71 ], dicationic ionic liquids [ 72 , 73 , 74 , 75 ], deep eutectic solvents [ 76 , 77 , 78 , 79 ], chiral ionic liquids [ 80 ], and solvate ionic liquids [ 81 , 82 ], have been synthesized for different aforementioned purposes.…”

Ecotoxicity and Hemolytic Activity of Fluorinated Ionic Liquids

“…The application of ILs in such broad range of fields are supported by their great tuneability, since their final properties are dependent on the cation-anion selected pair. Amongst the most advantageous properties of ILs are their high thermal stability and "green nature", endorsed by their low flammability and reduced vapor pressure [18][19][20][21], as well as by their biocompatibility and reduced environmental toxicity associated to several cation-anion combinations [22,23].…”