Synthesis and Application of Novel Heterobifunctional Reactive

Abstract

With the goal of improving the performance of traditional dichlorotriazine reactive dyes, three types of heterobifunctional reactive dyes were synthesized and evaluated in this study. Type 1 dyes were prepared by a reaction of one equivalent of a DCT-based parent dye with two equivalents of cysteamine followed by two equivalents of cyanuric chloride and para-aminobenzenesulfato-ethylsulfone. To make type 2 dyes, cysteine was used instead of cysteamine, and the synthesis of type 3 dyes employed a DCT-based parent dye, and one equivalent of cysteamine, cyanuric chloride, and para-aminobenzenesulfato-ethylsulfone.

The visible absorption spectra of the new reactive dyes showed a 7-17 nm increase in λmax compared to parent dichlorotriazine dyes. The structures of new dyes were supported by data from ESI mass spectrometry and results from HPLC analysis indicated that isomeric structures had formed, in which the reaction of cysteamine/cysteine simultaneously occurred at the —NH2 and —SH groups.

The application properties of the new dyes on cotton fabric were compared with those of the DCT-based commercial dyes. The results indicated that type 1 and type 3 dyes, which are derived from cysteamine, gave higher exhaustion levels and K⁄S values than the corresponding commercial dyes. Type 2 dyes, which are based on cysteine, did not have a good affinity for cotton. It is believed that the presence of a carboxyl group on the linking moiety distorts the geometry of the dye structure, giving an irregular shape.

The results of percent fixation studies showed that type 1 and type 3 dyes can be applied at a lower salt level (40g⁄L) than the commercial dyes and simultaneously give higher fixation and better leveling. Similarly, it was found that the fastness properties of type 1 and type 3 dyes are not adversely affected by modification of the commercial dyes.

The above mentioned results suggest that the new dyes can be used to produce standard depths using less dye and salt, giving the potential to reduce color and chloride in reactive dye wastewater.