Ionic Liquids – Further Progress on the Fundamental Issues

Abstract

Ionic liquids continue to challenge conventional descriptions of liquids and their behaviour. Indeed, the ever-increasing variety of ionic liquid compounds has generated a need for multiple descriptions of the different molecular families, including protic, aprotic, solvate, and metal coordination complex families of ionic liquids, that exhibit very different behaviours. Within families, the balance of long-range electrostatic and short-range dispersion forces plays out in nanoscale heterogeneity that also impacts markedly on properties. In this perspective, we highlight some of the issues in the field that continue to deserve further investigation and development at both the experimental and fundamental levels. We also propose a set of nomenclature abbreviations in an attempt to systematise the plethora of confusing abbreviations that appear in the field. The distinction between ionic liquids, ionic liquid–solvent mixtures, and deep eutectic solvents is also discussed.

Ionic Liquid-Polymer Nanoparticle Hybrid Systems as New Tools to Deliver Poorly Soluble Drugs

“…Due to these properties and to the ability to be modified according to a desired physicochemical property, they may be used for different purposes [1,6,8]. For instance, ILs have been applied in different fields, including in several organic reactions [15,16,17,18,19,20], in extractions and separation reactions [15,21,22,23,24], in electrolysis and electrochemistry [25,26,27,28] and in nanotechnology [9,28,29,30,31]. Another emergent application of ILs is as functional excipients, due to their ability to increase drug solubility and/or permeation and as drug stabilizers [1,2,3,5,8,12,32,33,34].…”

Anomalous and Not-So-Common Behavior in Common Ionic Liquids and Ionic Liquid-Containing Systems

“…Several high quality reviews (Welton, 1999, 2018; Plechkova and Seddon, 2008; Armand et al, 2009; Hallett and Welton, 2011; Niedermeyer et al, 2012; Tariq et al, 2012; Chatel et al, 2014; Hayes et al, 2015; Hunt et al, 2015; Podgoršek et al, 2016; Kar et al, 2019) are available. No review focused on the unexpected behavior of ILs has been published, where a scrutiny of their not so well known physical chemistry responses is made.…”

Tetraethylammonium Acetate and Tetraethylammonium Bromide-Based Deep Eutectic Solvents as Thermodynamic CO2 Gas Hydrate Inhibitors

“…Without covalent or ionic bonds, these components interact merely through intermolecular forces [24]. Detailed works comparing DES and ILs have been done, and DESs have been slowly replacing ILs in various fields [23][24][25][26][27][28][29][30][31][32][33]. DESs have great potential to be effective and eco-friendly Thermodynamic Hydrate Inhibitors (THIs) because DESs have functional groups capable of forming hydrogen bonds with water.…”