One-Step Dyeing and Antimicrobial Finishing of PET Fabric with Novel 4-Arylazopyrazolone Disperse Dyes

Azopyrazole disperse dyes 8-12 could be synthesized either by condensing ethyl 3-hydroxy-2-aryldiazenyl butenoates 3-7 with S-methyl hydrazine carbodithioate 1 or by coupling the parent pyrazole 2 with diazotized aniline, p-substituted anilines and/or 4-aminoantipyrine. These dyes were applied to polyester fabrics using a high-temperature dyeing method at 120 degrees C and displayed yellow to orange hues. Raman spectra of the dyed samples undoubtedly excluded ring dyeing and were found to agree with the proposed structures. The synthesized disperse dyes were found to possess very good dyeing properties, as indicated by color strength measurements, and all of them except dye 12 had a color strength (K/S) value ranging from 19-23. The dyed fabrics exhibited excellent fastness to washing and dry and wet rubbing as well as light fastness, which varied from moderate to very good. The antimicrobial activities of the synthesized pyrazoles 2 and 8-12 as well as the dyed fabric samples against Escherichia coli and Staphylococcus aureus were measured, and the results showed very good activity.