Interaction studies of imidazolium based ionic liquids with organic acids and acetophenone : thermodynamic, spectroscopic, and theoretical approaches

Abstract

Ionic liquids (ILs) are salts that are primarily composed of cations and anions. They exist as liquids below 100°C or at room temperature, which is why they are sometimes referred to as room-temperature ionic liquids (RTILs). These salts are receiving a great deal of attention in a wide range of fields of chemistry and chemical engineering, this is due to their fascinating physicochemical properties like low volatility, vapour pressure, high thermal, chemical stability, good electrical conductivity and low flammability. Amongst these, the most appealing property is their ability to be customized to fulfil individual needs for various applications. This is done by making changes to the N-alkyl substituents or the hydrogen atoms attached to the imidazolium ring of the cation as well as the anion constituent, thus varying their structure. To use ILs as solvents, it is necessary to know how they behave in the presence of other chemicals, like conventional solvents such as alcohols or carboxylic acids as well as water, which are widely employed in extraction and separation processes. The nature of ILs therefore has a significant impact on the efficiency of chemical processes (e.g. synthesis, extraction, and separation). It is worth mentioning that, adding a small quantity of one or more conventional solvents, changes the physicochemical properties of ILs dramatically. Mixtures of ILs provide knowledge of different types of interactions which are absent in their pure state. ...