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A clean and highly efficient alcohol oxidation, using hydrogen peroxide in the presence of l -aspartic acid coupled imidazolium based ionic liquid [L-AAIL], was achieved under solvent free condition with excellent yield. In this catalytic system, variety of alcohol including inactive aliphatic alcohol, could be completely oxidized with high conversion and selectivity. The catalyst can be recycled and reused for seven runs without any significant loss of its activity.

In the present work, a class of imidazolium based ionic liquid coupled with asparagine system was employed for asymmetric epoxidation. The heterogeneous catalyst exhibited excellent activity for epoxidation of α, β-unsaturated ketones, affording the corresponding epoxy ketones in the presence of hydrogen peroxide. The catalyst was easily recovered from the reaction mixture and reused for five consecutive runs.

An environmentally benign, cheap and reusable L-amino acid functionalized ionic liquid [L-AAIL]/AlCl3 was found to be an effective catalyst for the synthesis of 3,4-dihydropyrimidine-2-(1H)-thione derivatives in good to excellent yield under solvent-free condition. Compared with the classical Biginelli reactions, this method consistently enjoys the advantages of mild reaction conditions, easy work-up, and short reaction time. These one-pot three-component Biginelli products could be separated easily from the catalyst–water system, and the catalyst could be reused at least five times without noticeably reducing catalytic activity.

N-heterocyclic carbenes (NHC) are now commonly encountered in organometallic and inorganic coordination chemistry because of its environmental friendly nature as solvent and catalyst, high activity, selectivity and easily recovered materials that were used to replace the traditional volatile organic solvents which generally suffered from environmental problems. Benzimidazole based ionic liquids (BILs) offering a new possibility for developing environmentally-friendly basic catalyst with transition metal and non-transition metal (Ag, Au, Ru, Rh, Fe, Co, Cu, Cd and Pd). They are flexible, nonvolatile, noncorrosive and immiscible with many organic solvents. In this review, we wish to present an overview of the preparation and applications in various reactions like alkylation, arylation, etherification, benzoin reaction, aldol condensation and metal mediated catalyst in Suzuki, Suzuki–Miyaura, Heck cross coupling and reduction, also in electrochemical application (electrocatalyst), anion sensor, solar cell, proton conduction, malaria parasite, antimicrobial activity, etc.