The coupling of carbon dioxide (CO ₂ ) with epoxides with the formation of cyclic carbonates is a highly attractive 100% atom economic reaction. It represents a greener and safer alternative to the conventional synthesis of cyclic carbonates from diols and toxic phosgene.

Novel linear polyurethanes were synthesized by bulk polyaddition of diamines with two vegetable-based biscarbonates produced from oleic acid methyl ester. Internal carbonated fatty acid diester (ICFAD) and terminal carbonated fatty acid diester (TCFAD) were obtained by the reaction of their epoxide precursors with CO₂. Terminal epoxy fatty acid diester (TEFAD) was found to be more soluble and more reactive in CO₂ than internal epoxy fatty acid diester (IEFAD). Polyurethanes obtained by polyaddition of TCFAD and ICFAD with diamines exhibit molecular weights up to 13 500 g mol⁻¹ and glass transitions around −15 °C. Amide linkages were not observed when secondary diamine was used as the comonomer.

The cycloaddition of carbon dioxide onto propylene oxide catalysed by ammonium and guanidinium salts has been investigated using density functional theory (DFT) in order to understand the catalytic mechanism and the role of the cation and the anion. Two different possible pathways were considered, but it has been found that the one whereby the activation of the epoxide by the onium salt occurs before the addition of CO₂ was consistent with the experimental findings. The rate-determining step was found to be the ring opening of the epoxide that results from the nucleophilic attack of the anion of the catalyst on the non-substituted carbon of the epoxide ring. Moreover, we found that in order to have an efficient catalyst, it is necessary to have an anion with an ambivalent nature (a high nucleophilicity and good leaving group ability). Finally, it turns out that for a given anion, the guanidinium salt is more efficient than the ammonium salt in opening the epoxide ring, thanks to the ability of the guanidinium cation to form hydrogen bonds with the oxygen of the epoxide.

Fatty acid-based bis-cyclic 5-membered carbonates containing amide linkages were prepared from methyl 10-undecenoate. The reaction in bulk of these bio-based carbonates with a series of di-amines led to poly(hydroxyurethane amide)s with molar masses up to 31 000 g mol⁻¹. As expected, the so-formed bio-based thermoplastic poly(hydroxyurethane)s exhibit amorphous to semi-crystalline features with respect to the chemical structure of the monomers used.