Factors affecting the hydrolysis rate of reactive dyes

Factors affecting the hydrolysis rate of reactive dyes

There are many factors that affect the hydrolysis rate of reactive dyes, such as electrolyte concentration, temperature, dye bath pH, dye concentration and so on.

(1) The influence of electrolyte concentration: the higher the electrolyte concentration in the water-based dyeing bath, the more the dye is hydrolyzed.

(2) The influence of temperature: Increasing temperature will lead to more hydrolysis of reactive dyes.

(3) The influence of the pH value of the dye bath: by studying the relationship between the pH value of the medium and the degree of cellulose dissociation, it is found that the alkali concentration cannot be increased to make the pH value of the solution exceed 10-11. Because, at this time, all accessible hydroxyl groups in the cellulose are ionized, and increasing the pH will only cause its hydrolysis.

(4) The influence of dye concentration: increasing the concentration of reactive dyes in the solution will promote their aggregation, thereby reducing the rate of hydrolysis.

The reactivity of reactive dyes with water is also related to the chromophore in the dye molecule, because the chromophore affects the electron cloud density of the reaction center. If anionic groups are formed in the color system, the electron cloud density of the reaction center increases, thereby reducing the reactivity of the reactive dye with water.