The synthesis of a series af disperse dyes derived from 5 -pyrazolone-3-methyl-1- (m-nitrophenyl) is described The colour fastness of those dyes to washing, dry-heat and to artificial light (Xenom are fading lamp) are reported and found to depend en the influence of the substituents on the electron density around the azo-group. The visible absorption spectra of all the dyes showed that the colours of these dyes lie in the range of yeIlow - orange - red.
M A AHMED ,RAIZ UR REHMAN ,T H USMANI ,A AKHTAR ,I SIDDIQUI ,
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