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Green chemistry emphasizes designing novel routes to overcome health and environmental
problems that occur during a chemical reaction. Green solvents are used in place of conventional solvents
that are hazardous to both human and the environment. Solvents like water, ionic liquids, supercritical
CO2, biosolvents, organic carbonates, and deep eutectic mixtures can be used as green solvents.
The review focuses on the properties, applications, and limitations of these solvents.
The use of ionic liquids (ILs) as organocatalysts is reviewed for transesterification reactions, specifically for the conversion of nontoxic compounds such as dialkyl carbonates to both linear mono-transesterification products or alkylene carbonates. An introductory survey compares pros and cons of classic catalysts based on both acidic and basic systems, to ionic liquids. Then, innovative green syntheses of task-specific ILs and their representative applications are introduced to detail the efficiency and highly selective outcome of ILs-catalyzed transesterification reactions. A mechanistic hypothesis is discussed by the concept of cooperative catalysis based on the dual (electrophilic/nucleophilic) activation of reactants.
Ionic liquids as transesterification catalysts: applications for the synthesis of linear and cyclic organic carbonates
