Structural Effects on the Physico‐Chemical and Catalytic Properties of Acidic Ionic Liquids: An Overview

Abstract

Acidic ionic liquids (ILs) are key systems in synthesis and their performances depend greatly on their cation and anion structure and their liquid-state organization. This microreview reports several examples of Bronsted and/or Lewis acidic ILs that have been selected to highlight the main peculiarities of these systems potentially fundamental for rational design and development of new ionic media and catalysts. Fundamental physico-chemical properties, optimization of which through tailoring of molecular structures could favor more efficient and sustainable applications, are discussed

The impressive chemistry, applications and features of ionic liquids: properties, catalysis & catalysts and trends

“…Besides the anion effect, it is worth remembering that Brønsted acids have their acid strength increased in imidazolium-based ILs, 29,49 as discussed before.…”

Brønsted acids in ionic liquids: how acidity depends on the liquid structure

“…This explains why, typically, this system is not catalytically active. 39 From a practical viewpoint, when handling solutions of HOTf and HNTf 2 in ionic liquids, there is a safety benefit as the solutions do not fume like the corresponding neat acids, and are consequentially easier to handle. ACIDITY VS.…”

Synthesis of 2-arylbenzimidazoles under mild conditions catalyzed by a heteropolyacid-containing task-specific ionic liquid and catalyst investigation by electrospray (tandem) mass spectrometry

“…17 It is also known that Bronsted acids may behave as superacids when supported (or embedded) in ILs. 18,19 Initially , also detected in Figure 3) had its abundance considerably decreased, whereas the abundance of the triply charged anion PW increased. This trend shows therefore that the dissociation of the acid was even at a larger extent, in accordance with the expected acidic strength increase in the presence of the IL BMI.NTf 2 .…”