The Chemistry Of Synthetic Dyes. Reactive Dyes -

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

A major challenge where the dye reacts with water instead of the fibre, creating "spent" dye that must be washed away. 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 Common in dyes

Known for incredibly vivid and brilliant shades. There are two main types of reaction mechanisms: 1

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.