Preparation, characterization and application of amino acid-based green ionic liquids
A family of novel ionic liquids with amino acids and their derivatives as cations and environmentally benign materials as anions have been synthesized using easy preparation techniques. The ionic liquids obtained have the same characteristics as conventional imidazolium ionic liquids and the same chiralities as natural amino acids. Thermal stabilities, phase behaviour, viscosities and miscibilities of the representative family members have been investigated, generally showing no difference from conventional ionic liquids. These amino acid ionic liquids may be used as catalysts and “fully green” solvents in the cycloaddition of cyclopentadiene to methyl acrylate, which is a typical Diels–Alder reaction. This approach to treating amino acids and their derivatives can serve as an alternative to traditional ionic liquids having synthetic chemical components.