THE POTEBTLAL FOR NEW CHROMOPHORES:-
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THE POTEBTLAL FOR NEW CHROMOPHORES:-
New chromophore development has had notable successes recently recently Benzodifuranone chromophores for brilliant red disperse dyes have been pioneered by Zeneca Colours (now BASF) but are unlikely to find application as the basis of water-soluble dyes for cotton and wool, since the lactone ring in the chromophore is readily hydrolysed.In fact this latter aspect is utillised to advantage when applying this type of disperse dye to polyester, since the dyeing produced are readily alkali cleared, because the chromophore is discharged by alkali to a colourless compound. Undoubtedly it would be possible to develop yellows and blues based on benzo or naphthodifuranone chemistry and it is interesting to speculate that should azo dyes be limited by legislation, then the industry has the potential to develop a new class of chromophore based only on carbon, hydrogen and oxygen.
The brilliant red diphenyldiketopyrrolopyrrole was developed by Iqbal at Ciba and has resulted in widespread usage. The pigmentary properties of this chromophore are first class and has earned it the nickname 'phthalocyanine red'. The structure is shown in figure. This fairly recent discovery and the bringing to maket of these brilliant red chromophores must surely indicate that innovations in colour chemistry are still possible, and that future research may unlock new treasures. There is clearly a need to develop unmetallised turquoise blue chromophores of lower molecular size than copper phthalocyanine. Equally, intense, non-azo blues of the brilliance normally achieved with anthraquinone chemistry would be a market winner.
