Synthesis and properties of symmetrically substituted 4,4′-bis(1,3,5-triazinyl)-diamino stilbene-2,2′-disulfonic acid derivatives as UV absorbing and fluorescent whitening agents

Abstract

The fluorescence properties of textiles dyed with optical brighteners have been widely reported in literature. However, little sufficient study has investigated the UV protection properties of textiles dyed with fluorescent whitening agents (FWAs). This study reports the synthesis of a series of stilbene-triazine compounds and their performance on cotton fiber as UV absorbing and FWAs. Triazinyldiaminostilbene compounds were synthesized by reacting 4,4′-diaminostilbene-2,2′-disulfonic acid with 2,4,6-trichloro-1,3,5-triazine to give 4,4′-bis(4,6-dichloro-1,3,5-triazin-2-yl)aminostilbene-2,2′-disulphonic acid. This intermediate was further condensed in two steps with amines by nucleophilic substituents on their triazine moiety. The structure of synthesized compounds were characterized by spectroscopic techniques i.e. IR, UV, elemental analysis and conformed by proton NMR Spectroscopy. These compounds were applied to cotton fiber as fluorescent whitening and UV absorbing agents. Their performances were evaluated with regards to whitening effects, ultraviolet protection factor (UPF), degree of exhaustion and fastness test.