THE HYDROLYSIS KINETICS AND DYEING PROPERTIES OF 3'-CARBOXYPYRIDINO-TRIAZINE REACTIVE DYES

The kinetics of the hydrolysis of 3'-carboxypyridino-s-triazine reacti ve dyes were studied at 60-130 degrees C in a neutral medium using HPL C. A series of hydrolysis rate constants were obtained and the effects of pH and temperature on the reaction were evaluated. It was found th at pH is a key factor at low temperature, but that when the temperatur e was raised, temperature becomes the more important influence on the hydrolysis. The reactivities of the monochloro- and 3'-carboxypyridino -s-triazine dyes were compared and the results showed that the hydroly sis rate constants of the latter were two grades higher than those of the former. The dyeing properties were also examined and it was demons trated that the most favourable pH value for dyeing at high temperatur e is 8; the neutral medium employed in commercial processes is thus no t necessarily the optimum condition. (C) 1997 Elsevier Science Ltd.