Anthraquinonoid dyes (Part 1)
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Anthraquinonoid dyes:-
Anthraquinonoid dyes constitute a large group of dyes which are subdivided into various subclasses. The chomophoric system present in most of these dyes is the quinonoid or the presence of two keto groups in the system linked together by the chain of alternate double bonds. The auxochromes present are substitutents such as hologen, hydroxy, amino, their various alkyl, acyl, aryl or aroyl derivatives, etc. Anthroquinonoid dyes can be broadly classified based on their structureal configuration such as dyes in which anthraquinone structure is present, dyes in which fused aryl rings are attached to the anthraquinone structure like benzanthrone, Dibenzanthrone, anthranthrone, etc. and dyes in which fused heterocyclic rings attached to anthraquinone structure are present. From the application point of view the anthraquinone dyes can be divided as anthraquinone dyes other than vat dyes such as direct dyes, acid dyes, mordant dyes, disperse dyes, cationic dyes, etc. and anthraquinone vat dyes. The discussion of various subclasses of anthraquinone dyes are out of scope of this book. However, some representative classes and their examples are discussed in short.
