Non-Isocyanate Synthesis of Aliphatic Polyurethane by BiCl-Catalyzed Transurethanization Polycondensation.

Non-isocyanate polyurethane synthesis by non-Sn catalysis is an essential challenge toward green polyurethane synthesis. Bismuth compounds are attractive candidates due to their low cost, low toxicity, and availability to urethane chemistry. This work applied various Bi catalysts to the self-polycondensation of a bishydroxyurethane monomer and found BiCl to be an excellent catalyst through optimization. The catalytic activity and price of BiCl are comparable to those of BuSnO, while its toxicity is significantly low. BiCl is, therefore, a promising alternative to Sn-based catalysts in non-isocyanate polyurethane synthesis.