Catalysis of the reaction between isocyanates and protonic substrates. II. Kinetic study of the polyurea foaming process catalyzed by a series of amino compounds

The catalytic activity of secondary and tertiary amines were determined in the reaction of phenyl isocyanate with water and aniline, respectively, in dioxane at 25°C. The polyurea formation is largely controlled by a base‐type catalysis. However, this general behavior can be perturbed by steric factors, and still more obvious deviations appear with protic catalysts reacting rapidly with the isocyanate. The resulting urea or urethane groups can display a significant activity in relation to the nature and the composition of the reaction medium. Very good quality foams can be obtained with these protic catalysts.