Design and application of a multifunctional reactive dye capable of high fixation efficiency on cellulose

A polyfunctional reactive dye containing two dichloro‐s‐triazine residues linked through aliphatic amino groups via a third triazine system to the chromophoric residue has been prepared. The dye was synthesised stepwise from a specially synthesised 2,4‐dichloro‐s‐triazine dyes. The first step is the reaction of both carbon–chlorine sites in the ‘parent’ dye with 2 mol ethylenediamine under selected conditions of pH and temperature; these conditions ensure that only one of the amino groups in the ethylenediamine will react to give the bis‐2,4‐aminoethyleneaminotriazine dye. The second step is the condensation of 2 mol cyanuric chloride with the two pendant primary amino groups. The alkylamino‐linked dichloro‐s‐triazine dyes show very different dyeing properties when compared with those shown by the parent dichloro‐s‐triazine dye, which has the reactive group linked directly into the aromatic chromophore; in particular, the new dyes have high fixation efficiencies when dyed on cotton at 50 °C and the dye–fibre bond stability to boiling acidic conditions is very good.