Synthesis of new congo red derivative dyes and their application as hardness reduction in hard water

Azo dyes are exceptionally important in a variety of industries for diverse technical purposes. synthesis of new congo red derivatives (6a-j) was achieved by diazotization of congo red at low temperature followed by coupling with a number of different coupling partners 5a-j in basic medium. the structures of newly synthesized dyes were confirmed using elemental and spectral data. the synthesized dyes were tested for their ion scavenging properties in hard water. compounds 6b-d and 6h-i were found to be successful in decreasing the water hardness,making them valuable candidates for water treatment in boilers and cooling towers in the chemical industry. © 2017,chemical society of pakistan. all rights reserved.