Tertiary amines: A new class of highly efficient organocatalysts for CO₂ fixations

To realize a true green CO₂ utilization process, the development of a catalytic system having no toxic components is essential. Herein, tertiary amines without any metal or halide additives are introduced as simple and green organocatalysts to activate CO₂ and insert into epoxides, producing synthetically important cyclic carbonates. Among those amines, diamine such as N,N,N′,N′-tetraethylethylenediamine exhibited a moderate to excellent efficiency. This new class of organocatalyst which does not have any toxic metals and halides is easy to handle and only requires as low as a 0.1 mol% loading. Additional favorable features include solvent free conditions and broad substrate scopes.