Synthesis of biscoumarin bifunctional reactive fluorescent whitening agents and their application on nylon-6 fabric

Two new bifunctional reactive fluorescent whiting agents based on joining two coumarin moieties together through triazinyle-stilbene fluorescent moiety have been successfully synthesized, applied on nylon-6 fabrics and then characterized by NMR and elemental analysis. Spectral properties, such as absorption and emission spectra in solution and on fabrics are investigated. The application of all the prepared compounds as fluorescence [fluorescence whiting agents (FWAs)] and their whiteness as well as light fastness properties on nylon-6 fabric have been compared with monofunctional agent. Despite the fact that the FWAs, containing either mono or bis methyl coumarin derivatives, show better whiteness properties than the FWA containing phenyl coumarin derivative, the later compound shows higher light fastness (excellent).