Design, synthesis of novel bisazo disperse dyes: Structure analysis and dyeing performance on PET

To achieve bisazo disperse dyes with better dyeing performances, novel bisazo disperse dyes based on butane1,4-diyl bis(ethyl(phenyl)carbamate) were synthesized by coupling with diazonium salts. Butane-1,4-diyl bis (ethyl(phenyl)carbamate) was prepared by condensation of 1,4-butanediol and N-ethyl-N-phenylglycinoyl chloride. N-ethyl-N-phenylglycinoyl chloride was achieved from N-ethyl-N-phenylglycine, which was hydrolyzed from ethyl N-ethyl-N-phenylglycinate. Compared with previously reported bisazo disperse dyes' low exhaustion, poor fastness performance or monotone color, constructed symmetrical bisazo disperse dyes exhibited excellent dyeing performance on polyethylene terephthalate (PET) fabrics, by introducing 1,4-butanediol as soft chain to lessen structure hardness of dye molecule and stronger hydrophobicity. Enhanced affinity between dye molecular and fiber was achieved by ester groups existing both in dye molecular and fiber, increased molecular size also enhanced stronger Van der Waals force and hydrogen bonding. Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance techniques (1H NMR) were used to confirm the structures of synthesized dyes. UV-Vis method was applied to estimate relationship between spectral properties and structures. Constructed bisazo disperse dyes were applied on polyethylene terephthalate (PET) fabric using conventional high temperature dyeing method under pressure, gave orange to blue shade with satisfying fastness properties. Quantum simulation was applied to provide a new guide line to evaluate structure-property relationship for dyestuffs.

Automated summary

Novel bisazo disperse dyes based on symmetrical structures were successfully synthesized, showing improved dyeing performance on PET fabrics by introducing 1,4-butanediol as a soft chain to enhance affinity with fibers. The use of ester groups in both dye molecules and fibers, along with increased molecular size, resulted in stronger Van der Waals forces and hydrogen bonding, contributing to the enhanced dyeing properties.