The synthesis and properties of benzoxazole fluorescent brighteners for application to polyester fibers

Fluorescent brighteners based on dicarboxylic acid derivatives are compounds of the benzoxazole type, synthesized by a simple reaction using polyphosphoric acid. The obtained compounds (4a–c, 6a–c, 8a–c) were characterized by the analysis of proton NMR spectrum and confirmed by UV spectrum. The physical properties of the compounds (4a–c, 6a–c, 8a–c) were performed by fastness test and whiteness measurement.