Abstract
Hydroxymethylation of melamine with formaldehyde was kinetically investigated in aqueous sodium hydrogencarbonate-sodium carbonate buffers in the range of pH 8.89 ([HCO-3] / [CO2-3] =7.0) -10.57 ([HCO-3] / [CO2-3] =1/7) at 20°C. The unreacted melamine was determined by means of high pressure liquid chromatography with an ultraviolet spectrophotometer, and the rate equation and constants were obtained. The rate constants for sodium hydroxide catalyst and those without additional catalyst were also estimated. By the use of the rate constants of the general-base catalyzed reaction thus obtained, Brönsted plot was established, and the reaction mechanisms were postulated.
