Synthesis And Use Characterization Of Antimicrobial Monoazo Dyes Incorporating Quaternary Ammonium Salts

Bacteria can grow on the surface of textiles because fibers may provide bacteria allrequirements including nutrients, water and warmth. Sometimes bacteria growths on textilesgenerate adverse effects, such as, odor generation, PH charges, staining, and loss ofperformance. These adverse effects may threat user's health, deteriorate textile performancesand degrade services. Production of antimicrobial textile and antimicrobial finishing ofordinary fiber are current approach, Appearance of antimicrobial dyes provide anothereffective approach. In this paper, ten dyes having no previous reports are synthesized byintegrating quaternary ammonium salts into dye structure. Their structures are determinedusing FF-IR, ¹H NMR, ¹³C NMR, and ESI-MS analysis. Nine (three series) antimicrobialcationic monoazo dyes are prepared by a diazotization-coupling reaction involving twoaromatic amino compounds (featuring different chain length alkyl quaternary ammonium salts)as diazo components, and N, N-dimethyl-benzeneamine and 1-phenyl-3-methyl-5-pyrazoloneas coupling components. Nine cationic dyes are yellow. Dye H1 is prepared by adiazotization-coupling reaction involving aromatic amino compound (featuring dodecylquaternary ammonium salts) as dizao component, and H acid as coupling components. DyeH1 is a red dye.The spectrum characterization of ten dye aqueous solutions is studied. It was found thatalkyl chain length do not significantly affectλ_max among the nine cationic dyes. Withinpyrazolone series dyes (dye series 2 and 3), absorption decreases as alkyl chain lengthincreases, but aniline series dye (dye series 1) shows the opposite trend.There is azo-hydrazone tautomer in the structures of pyrazolone series dyes and dye H1.For example, adding acid or alkali into dye 2c aqueous solution may transform each otherbetween azo-hydrozone tautomer. Dye 2c aqueous solution is hydrozone structure in acidenvironment. Dye 2c aqueous solution is azo structure in alkali environment.Acrylic fabrics were dyed with nine cationic dyes by traditional cationic dyeingprocedures and the exhaustion of dyes is close to 100%. Differing dye structure and alkylchain length have an influence on the dyeing properties of acrylic fabrics.The colorfastness of nine dyes is tested. It was found that pyrazolone series dyes ownbetter colorfastness. The antimicrobial activities of ten dyes are tested and tested bacteria are Staphylococcusaureus and Escherichia coli.Minimum inhibitory concentration (MIC) data shows the efficacy of nine cationic dyesagainst both Staphylococcus aureus and Escherichia coli. Nine dyes are especially sensitiveto Staphylococcus aureus. Alkyl chain length and different dye structures have effects on theantimicrobial activity. The bacteria reduction ratio of dyed fabrics exceeded 70%.Antimicrobial activity of acrylic fabrics gradually fades away.Dyeing and simultaneous antimicrobial finishing of acrylic fabrics is carded out withnine cationic dyes, and economizes energy and water, and has great environment protectionsignificance.Nine dye aqueous solutions and acrylic fabrics treated with antimicrobial cationic dyesshow better antimicrobial efficacy against Staphylococcus aureus than Escherichia coli.The antimicrobial effcacy of dye H1 aqueous solution is so weak that dyed fabricstreated by dye H1 (depth of shade 1%) show no antimicrobial activity.The dyeing characterization of Dye H1 is studied, and Dye H1 may dye wool fabrics withoutsalts, and decreases environment pollution. The colorfastness of fibrics did not high, but itprovided a promising method for salts-free dyeing.