The — Chemistry Of Synthetic Dyes. Reactive Dyes

The part that provides color (usually azo, anthraquinone, or phthalocyanine groups). Solubilising Group: Often sulfonic acid salts ( SO3Nacap S cap O sub 3 cap N a ) that make the dye water-soluble.

Common in dyes. The chlorine atom on the dye molecule is displaced by the hydroxyl ( OHcap O cap H ) group of the cellulose or the amino ( NH2cap N cap H sub 2 ) group of protein fibres. Result: A stable carbon-oxygen or carbon-nitrogen bond. 2. Nucleophilic Addition The Chemistry of Synthetic Dyes. Reactive Dyes

The dye attaches to the fibre through a chemical reaction triggered by alkaline conditions (high pH). There are two main types of reaction mechanisms: 1. Nucleophilic Substitution The part that provides color (usually azo, anthraquinone,