Melamine formaldehyde compounds. The active species in acid catalyzed reactions

Applying results from previously published kinetic investigations on the hydrolysis and condensation of methylol melamine compounds in acid solution a thorough analysis of the reaction mechanism is given. In the literature it has been discussed whether the acid catalysis takes place by protonation of the triazine ring, if it is a protonation of the methylol side groups or if both types of protonation are active. In the present paper strong support is given to a kinetic model where the side group activated species are the reactive ones. Ring protonation, on the other side, leads to deactivation. Included are also computer simulations in Matlab of the decomposition of tri- and hexa-methylol melamine in dilute solution, assuming the hydrolysis to take place by series first order reactions. The computer simulations allow us to calculate the relative composition of the reaction mixture as a function of time and to see the effect of changes in the experimental rate constant as the reaction proceeds.