Components Required for Various Types of Dyes 1. ...

Components Required for Various Types of Dyes 1. Azo Dyes Structure: Characterized by -N=N- (azo) group Used in: Cotton, wool, silk, leather 🧪 Key Components: Diazo Component: Aromatic amines like Aniline, Toluidine, Sulfanilic acid Coupling Component: Phenols, naphthols like β-naphthol, resorcinol Oxidizing Agents: Sodium nitrite (NaNO₂), hydrochloric acid for diazotization Acid/Base: Sodium carbonate, acetic acid 2. Reactive Dyes Structure: Contains reactive groups that form covalent bonds with fibers Used in: Cotton, rayon, wool 🧪 Key Components: Chromophores: Based on azo, anthraquinone, or phthalocyanine Reactive Groups: Vinyl sulfone, triazine, monochlorotriazine (MCT) Linking Agents: Cyanuric chloride, sulphatoethylsulphone Auxiliary Chemicals: Sodium carbonate, sodium chloride (for fixation) 3. Vat Dyes Structure: Water-insoluble, reduced to soluble form and oxidized back on fabric Used in: Denim (Indigo), cellulosic fibers 🧪 Key Components: Base Chromophores: Indigo, anthraquinone derivatives Reducing Agents: Sodium hydrosulfite (Na₂S₂O₄) Alkali: Caustic soda (NaOH) Dispersing agents 4. Acid Dyes Structure: Water-soluble, applied in acidic conditions Used in: Silk, wool, nylon 🧪 Key Components: Aromatic Amines: For diazotization Sulfonic Acid Groups (-SO₃H): Enhance water solubility Couplers: Phenol, amines Acids: Acetic acid, formic acid for pH control 5. Disperse Dyes Structure: Nonionic, low solubility, used for hydrophobic fibers Used in: Polyester, acetate 🧪 Key Components: Aromatic Compounds: Benzene, anthraquinone, nitrobenzene Nitro Derivatives Acetylating agents: Acetic anhydride Dispersing agents: Lignin sulfonate, naphthalene sulfonates 6. Direct Dyes Structure: Large planar molecules with affinity to cellulose Used in: Cotton, viscose 🧪 Key Components: Azo Compounds Sulfonic Acid Derivatives Phenyl and Naphthylamines Salt (NaCl): Helps fix dye on fiber 7. Basic (Cationic) Dyes Structure: Positively charged; high affinity for negatively charged surfaces Used in: Acrylic fibers, paper, jute 🧪 Key Components: Aromatic Amine Bases: Aniline, benzidine Alkyl Halides: For quaternary ammonium salts Solvents: Alcohol, water 🧭 Supporting Chemicals Common Across Dye Making: Solvents: Water, ethanol, methanol pH Adjusters: NaOH, HCl, acetic acid Stabilizers: Urea, surfactants Intermediates: H-acid, J-acid, Tobias acid, naphthionic acid, etc.