Aromatic guanidines as highly active binary catalytic systems for the fixation of CO2 into cyclic carbonates under mild conditions

We have synthesised a set of aromatic mono- and bis(guanidines) which are highly effective binary catalytic systems (guanidine/cocatalyst) for the formation of cyclic carbonates. The presence of multiple N-H bonds causes a modification in the traditional mechanism proposed for the synthesis of cyclic carbonates catalysed by guanidines through the formation of hydrogen bonds between the oxygen atom of the epoxide and the N-H groups of the guanidines. This change allows a considerable reduction of the reaction temperature and CO2 pressure employed in this process.