Depending upon the number of azo-groups present they are called as monazo, disazo, trisazo, tetrakisazo and polyazo dyes. All types of azo-dyes amount to over one thousand, commercially most important class of synthetic coloring compound. It has wide variety of applications. Anthraquinone Dyes Anthraquinone is the basic unit of this class of dyes. Introduction of hydroxyl and amino groups in anthraquinone a wide range of colors are available.
Dyes containing anthraquinone unit belong to mordant, disperse and vat dyes.
Its quinonoid system acts as a chromophore. Anthraquinone dyes have excellent fastness properties. Disperse dyes Dyes generally use to dyecellulose acetate, nylon and other hydrophobic fibres are called disperse dyes. They are also known as acetate dyes. Dispersal and cellitoin are the important dispersing agents.