Chiral Ionic Liquids from Amino Acids and Terpenoids: Synthesis and Applications

Ionic liquids (ILs) are widely useful as catalysts or as a medium for reactions in varied chemical processes since they possess environment-friendly chemical/physical properties. Ionic liquids (ILs) are those chemical entities that consist of a cation and an anion having melting points less than 100 °C. Since the last decade, there has been an increase in the number of chiral ionic liquids (CILs) and their applications. Most chiral ILs have either a chiral cationic or chiral anionic center. There are also some CILs with both chiral cationic and chiral anionic centers. Molecules obtained from nature (biomolecules) are mostly degradable; a number of them are not toxic and are sustainable in nature. So, the development of CILs from biodegradable biomolecules provides an opportunity to further improve their greener aspects. Amino acids are a special kind of biomolecule due to their easy conversion into both anions and cations; the diverse functionalities in their side chains make them chiral and also enhance their properties. In comparison to various other chiral molecules, amino acids are cheaper and plentiful. In the last few years, an array of novel chiral ionic liquids were synthesized from simple, economical, naturally occurring terpenoids. In this chapter, very recent developments about the amino acids and terpenoid-based CILs have been reported and reviewed.