The Chemistry Of Synthetic Dyes. Reactive Dyes -

While reactive dyes are safer than many older synthetics (like those using heavy metals), they require large amounts of salt and water for the fixation and rinsing processes. Modern research focuses on "low-salt" dyes and increasing the to reduce chemical waste.

Generally requires salt to drive the dye into the fibre and alkali to fix it. 🌍 Environmental Impact

The "business end" that reacts with the fibre (e.g., vinyl sulfone or cyanuric chloride). 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

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. While reactive dyes are safer than many older

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

Known for incredibly vivid and brilliant shades. 🌍 Environmental Impact The "business end" that reacts

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