Abstract


Some new acid dyes have been synthesized bycoupling tetrazotised 4, 4-methylene-bis (2, 5-dimethyl aniline) (2) withdifferent coupling components (3a-f) and their dyeing performance on wool, silkand nylon have been assessed. They are characterized by their elementalanalysis, UV-visible spectra, IR and PMR spectra. All the dyes showed goodexhaustion and fixation properties. All the dyes show generally moderate tovery good light fastness properties. The washing and rubbing fastness propertiesranges from good to excellent fastness on wool and silk and nylon.


Keywords


4,4-methylene-bis(2,5-dimethyl aniline),Exhaustion, Fixation, Light Fastness, Wash Fastness and Rubbing Fastness.


Introduction


Acid dyes are water-soluble anionic dyes that areapplied to nitrogeneous fibres such as wool, silk, nylon and modified acrylicfibres from acid or neutral baths. Attachment to the fibre is attributedatleast partly to salt formation between anionic groups in the dyes andcationic groups in the fibre. Acid dyes are not substantive to cellulosicfibres. The acid dyes were probably originally so named because of the presenceof one or more sulphonic acid or other acidic groups in their molecules. Theterm applies to an application class rather than a chemical class however, andsince acidic groups are also present in many mordant, direct and reactive dyestheir presence is not a distinguish feature.


Aciddyes can easily be applied on wool, silk and other protein and polyamide fibresand therefore are largely used. They are applied generally in the presence ofan organic or an inorganic acid and hence are called acid dyes. Acid dyes, thenewest addition of existing dyes are the centre of attraction in dyestuffresearch1. Acid dyes have found wide application in dyeing wool,polyamide fibers and blends of both these fibers but they have to meet veryhigh requirements as regards their application and fastness



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The Authors are associated with Department of Chemistry, Veer Narmad South Gujarat University,Udhana-Magdalla road, Surat, Gujarat, India.