Catalytic systems for the synthesis of biscarbonates and their impact on the sequential preparation of non-isocyanate polyurethanes

The synthesis of non-isocyanate polyurethanes (NIPUs) have recently gained great attention. In this respect a bifunctional catalyst and an abundant metal catalyst system were investigated for the conversion of polyfunctional epoxides to gain general access to the corresponding cyclic carbonates as monomers for NIPU synthesis. An Ca-based catalytic system and a bifunctional ammonium salt were established for the synthesis of these monomers. In total, 14 terminal polyfunctional epoxides were converted to the corresponding carbonates in yields up to 99% and high purities. With regard to the one-pot synthesis of NIPUs directly from epoxides and CO2 the influence of the catalyst systems were evaluated. In general both catalytic systems allowed the synthesis of NIPUs in a sequential one-pot procedure yielding polymers with a molecular mass of up to 19 kg·mol–1.