Isocyanates Bloques: Etude Cinetique Et Thermodynamique

Abstract

Abstract A kinetic and thermodynamic study of the deblocking of urethanes is presented; the blocking agents are phenols, aliphatic alcohols and a polyether. The deblocking occurs via the elimination‐addition mechanism. In the transamination reaction, the rate determining step is the amine catalyzed dissociation of the blocked isocyanate. The equilibrium constants of these reactions give the relative stability of blocked isocyanates. The dissociation equilibrium of several urethanes were also determined; temperature higher than 170°C are required to obtain a significant dissociation in the case of usual urethanes.