Synthesis and application of a novel, triphendioxazine-based, phosphorus-containing acid dye for wool

A novel phosphorus-containing acid dye based on triphendioxazine was designed and synthesised from diphenylamine through a series of reactions. The dye has a navy-blue colour, high molar extinction coefficient of 5.32 x 10(4) l/mol<bold>cm</bold>, and high substantivity for dyeing wool in a salt-free, aqueous dyebath. A high exhaustion value of 98.2% on wool fabrics was recorded at 3% omf and a liquor ratio of 1:20. The wash fastness values of the acid dye, including colour change and staining on cotton and wool, were grades 5, 4 and 4-5, respectively. The dry and wet fastness are grades 4-5 and 4, respectively. In addition, light fastness reaches grades 6-7 at 3% omf dye concentration. These dye properties are better than those of commercial triphendioxazine dyes, for example, CI Direct Blue 106 and CI Reactive Blue 198, under analogous dyeing conditions.