Carbocyclic Azo Dyes

Carbocations, 12 161—162, 163 from alkanes, 12 187 Carbocation salts, stable, 14 269 Carbochlorination, zircon, 13 82 Carbocyclic azo dyes, 9 245, 251 Carbodiimide (CDI) method, for covalent ligand immobilization, 6 396t Carbohydrate chemistry, microwaves in, 16 547-548... 

Carbocyclic azo dyes are the backbone of most commercial dye ranges. Based totally on benzene and naphthalene derivatives, they provide yellow, red. blue, and green colors for all the major substrates such as polyester, cellulose, nylon, polyacrylonitrile, and leather. 

The carbocyclic azo dye class provides dyes having high cost-effectiveness combined with good all-around fastness properties. However, they lack brightness, and consequently, they cannot compete with anthraquinone dyes lor brightness. This shortcoming of carbocyclic azo dyes is overcome by heterocyclic azo dyes. 

Most azoic dyes belong to the carbocyclic azo class, but these dyes are formed in the fiber pores during the application process. 

Diazo Components With Cycloammonium Groups. Polynuclear N heterocycles that carry an amino group in the carbocyclic aromatic ring can be diazotized and then joined to azo dyes by using aromatic or heterocyclic coupling components. Quatemization at the heterocyclic nitrogen atom may occur before or after coupling. The azo dye 43, from 2-methyl-5-aminobenzimidazole and l-phenyl-3-methyl-5-pyrazolone, used in the form of its hydrochloride, dyes paper and leather in clear yellow shades [130],... 

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