What are Reactive Dye? History of reactive dye?

A dye, which is capable of reacting chemically with a substrate to form a covalent dye substrate linkage, is known as reactive dye.

Here the dye contains a reactive group and this reactive group makes covalent bond with the fiber polymer and act as an integral part of fiber. This covalent bond is formed between the dye molecules and the terminal –OH (hydroxyl) group of cellulose fibers on between the dye molecules and the terminal –NH2 (amino) group of poly-amide or wool fibers.

Reaction:

D-SO2-CH2-CH2-OSO3Na +OH-cell     =>      D-SO2-CH2-CH2-O-cell + NaHSO3

D-SO2-CH2-CH2-OSO3Na + NH2- wool   =>    D-SO2-CH2-CH2-NH-Wool + NaHSO3

Here, D= dye part.

Wool = wool polymer.

Cell = cellulose polymer.

Reasons for so named of Reactive dye

Reactive dyes are so called because this is the only type of dye, which has reactive group, and that reactive group reacts chemically with fiber polymer molecules and form covalent bond. This covalent bond is formed between the reactive group and terminal –OH (Hydroxyl) group of polyamide and wool fiber or between reactive group and terminal    -NH2 (Amino) group of cellulosic fiber polymer. The strength of this covalent bond is more than ionic bond, hydrogen bond and Vander Waal’s force of attraction. Thus the reactive group becomes an integral part of the fiber.

For this reasons the dyes are so called. They are also called ‘fiber reactive group’.

History of reactive dye:

On the occasion of 100 year’s celebration of synthetic dye manufacturing, two chemists of ICI company (UK) named Stephen and Rattee tried to manufacture a new dyestuff. Thus they succeed to invent a new dye in 16965, which was named REACTIVE DYE. This was manufacture for dyeing cellulosic fabrics. The first three reactive dyes were PROCION YELLOWR, PROCION BRILLIANT RED 2B and PROCION BLUE 3G.for this effort they were awarded gold medal of the society of dyes and colorists for the year 1960. 

Reactive Dyes :

Form a covalent bond between the dye and fiber

Introduced to the market by ICI in 1956.

Inspired by esterification of cellulose in 1895 with benzoyl chloride

Show improved fastness properties

Great improvement for cellulosic fibers

Simplify dyeing procedure

No oxidation / reduction.