Diffusion with simultaneous reaction of reactive dyes in cellulose

Abstract

SynopsisThe theoretical equations which described the concentration profile of immobilized species of reactive dyes in the substrate were derived from the diffusion equation with the chemical reaction of first-order or pseudofirst-order. The theoretical profiles in the substrate described by the equations were discussed. The larger the diffusion coefficient D of active species and the smaller the reaction rate constant h , the deeper is the penetration of the immobilized and active species of reactive dyes into the substrate. The method of estimating D and k from the diffusion profiles of both species obtained by means of the method of the cylindrical cellophane film roll was described.The diffusion coefficients of the hydrolyzed species of C.I. Reactive Orange 1 and Red 1 were nearly constant in all the pH values examined. The concentration profiles of both the species of Orange 1 at pH 8.8 were identical with the theoretical ones; while the profiles of immobilized species of Red 1 at pH 10 and of Orange 1 a t pH 12 agreed with the theoretical ones and those of active species did not because of the hydrolysis. The diffusion coefficients of active species of these dyes a t these pH ranges were smaller than those of the hydrolyzed species.

Diffusion and simultaneous reaction in cellulose of reactive dyes bearing various reactive groups.

“…On integrating the equation by t and further by x, equations giving the concentration profile of the fixed and the active species in the substrate were derived. 32,33,35) Most of the experimental profiles of the active and the fixed species agreed well with the theoretical profiles drawn according to above equations. some examples are shown in Figures 1 and 2, where the theoretical average concentration (mol/ kg) of the active (Ci) and the fixed (C1 ?? )…”

“…21,22,28) In the previous studies , the diffusions with simultaneous reaction in cellulose for mono -and dichlorotriazinyl and vinylsulfonyl reactive dyes were investigated by the cylindrical film roll method. [29][30][31][32][33] The pseudofirst -order rate constants of reaction with cellulose, the diffusion coefficients and the surface dye concentrations under various conditions were evaluated from the diffusion profiles of the active and the fixed species.…”

“…In order to elucidate the effect of the reactive groups on the mechanism of dyeing, the results were compared with those obtained in the previous studies. [29][30][31][32][33] 2. EXPERIMENTAL Samples of reactive dyes used and the experimental conditions are shown in Table I.…”

Reaction of Dichlorotriazinyl Reactive Dyes With Cellulose and Simultaneous Diffusion in Cellulose

“…The values of D for the hydrolyzed and active species over the pH range [7][8][9][10][11][12] are shown in Fig. 4.…”

“…The experimental profiles of re- In the present paper, five dichlorotriazinyl reactive dyes are examined by the same methods as reported in the previous papers10-12) in order to obtain general dyeing properties of dichloro triazinyl dyes. These eight dyes, including three dyes examined previously, [10][11][12] are the same as used by Ingamells et al2) In this paper, the hydrolysis and the reaction with cellulose will be compared, and relationships among the diffusion, the reaction with cellulose and with water in cellulose, the hydrolysis in the dyebath, the affinity and the molecular structure will be also discussed. 3.1 Reaction with Cellulose and Water in Cellulose As the dichlorotriazinyl reactive dyes have a high reactivity, the higher the pH, the faster the hydrolysis in cellulose may become.…”