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.

Ghulam Shabir and Aamer Saeed