Structure And Photolytic Properties Of Ortho Substituted Monoazo Dyes And Disazo Disperse Dyes PDF Download

A general survery of the preparation and application of disazo dyes, imidazole dyes, pyrazole dyes and their related intermediates has been made. A range of disazo dyes has been prepared by the synthesis of the ... methanesulphonate salts of aniline and its substituted analogues, and their subsequent coupling reaction in the synthesis of the intermediate monoazo dye followed by a second diazotization and coupling reaction to give the required disazo dyes. Colour-structure relationships are discussed, and PPP MO calculations used to evaluate colour and structure relationships. The synthesis of a series of azo colourants from diazotised arylamines and 4(5)-cyano- 5(4)-hydroxyimidazole is described. The dyes exhibit a large bathochromic shift of the visible absorption maxima relative to analogous dyes derived from carbocyclic coupling components. A series of pyrazolyazo dyes was also synthesized, the hues of which varied from yellow to red. The dyes did not a exhibit bathochromic shift of the visible absorption maxima relative to analogous dyes derived from carbocyclic diazo components, but gave bright hues characteristic of heterocyclic dyes. The colour-structure relationships are discussed.