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.