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) has 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. A 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 was 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).