Links the chromophore to the reactive system. ⚗️ The Reaction Mechanism
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.
Excellent, because the dye is chemically locked to the fibre. 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.
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 Links the chromophore to the reactive system
Generally requires salt to drive the dye into the fibre and alkali to fix it. 🌍 Environmental Impact
Typical of dyes (like Remazol). In an alkaline bath, the dye undergoes an elimination reaction to form a vinyl sulfone group, which then adds across the fiber's functional groups. Result: A highly durable covalent linkage. ⚡ Key Properties Excellent, because the dye is chemically locked to the fibre
The chemistry of reactive dyes centers on their unique ability to form a permanent covalent bond with the substrate, typically cellulose (cotton) or protein fibres (wool/silk). Unlike other dyes that simply "sit" on or inside the fibre, reactive dyes become a chemical part of the fibre itself. 🧪 Chemical Structure Reactive dyes consist of four primary components:
Classen Becker
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