Ionic liquids synthesis and applications: An overview

Over the past two decades, ionic liquids (ILs) have had a wide range and cutting-edge impact, generating promising science and technologies and have also expanded exponentially in terms of their publications. They have been utilized for both academic and industrial applications. They are potential candidates for solving some of the major issues society is currently faced with by emerging as a clean, efficient, and eco-friendly alternative resource of volatile organic solvents along with many more significant benefits due to their unique thermal, physical, chemical and biological properties. Furthermore, these properties could be modified depending on their application by altering the combination of cations and anions. However, their synthesis and purification require standard synthesis methods to certify their consistent reproducibility. The yields from ILs at large scales for the industrial applications along with their synthesis, toxicity and environmentally friendly nature have become the main concerns. The aim of this review is to investigate the current literature that describes the cutting-edge-knowledge regarding the synthesis of various classes of homogeneous (task specific-ILs, chiral-ILs, switchable polarity solvent ILs, bio-ILs, poly-ILs, energetic-ILs and many more) and heterogeneous (supported-ILs) ILs. Fundamental aspects of ILs such as the green aspects, environmental impacts and purity of ILs are also discussed. The potential applications of ILs in electro-chemistry, solvent, engineering, catalysis, biological aid, physical chemistry, analytical chemistry and many more are briefly explained. In addition, the explanations based on purifications and recovery of ILs by using single or combined methods along with their physico-chemical properties were also reviewed. Moreover, the comprehensive study summarizes the latest progress on assorted classes of ILs along with discussing their prospective applications in the first half. The synthesis of homo/heterogeneous ILs is thoroughly elaborated in the second half. Finally, the future prospective medical applications of ILs are also mentioned.