Organocatalytic synthesis of (poly)hydroxyurethanes from cyclic carbonates and amines

摘要

The organocatalyzed aminolysis of cyclic carbonates to form (poly)hydroxyurethanes is an important reaction as an alternative to isocyanate based chemistries. In an effort to increase reaction rates between cyclic carbonates and amines to lower cure times and increase molecular weights, various organocatalysts were surveyed. Reaction rates between monofunctional model cyclic carbonates and amines were determined in the presence of a variety of organocatalysts, which operate under different mechanisms to promote the reaction. Of the catalysts investigated, TBD was the most potent, presumably due to its bifunctional activity. TBD was also used to promote step-growth polymerization between difunctional cyclic carbonates and amines. The polymers produced in the presence of TBD at room temperature were much higher in molecular weight than polymers produced in the absence of catalyst at both room temperature and at 80 C.