Effect of thiophene, furan moieties and zinc ions on melamine-based porous polyaminals properties and catalytic activity on CO2 cycloaddition reaction

A new series of melamine-based porous polyaminals containing thiophene or furan moieties of different size in the polymer network were prepared and fully characterized. The new polyaminals were N-rich polymers with nitrogen content between 10 and 28%, exhibited micro-, meso- or macroporosity, depending on the type and size of the thiophene or furan moiety with specific surface areas in the range of 23–490 m2/g. The CO2 uptakes were moderated, between 1 and 5% and those polyaminals with higher CO2 uptake capacity were selected as catalysts to promote the conversion of CO2 into cyclic carbonate and also to prepare the corresponding zinc complexes, which were used as catalysts in the same reaction. The selected catalysts showed good catalytic performance working under much milder reaction conditions (CO2 pressure of 4 bar, 80 °C, 0.1 mol % of cocatalyst) than the examples of melamine-based polyaminals published so far for this reaction.