Green synthesis of reactive dye for ink‐jet printing

Abstract

Chloropyrimidine‐based reactive dyes are reported as well suited to textile printing; however, nucleophilic aromatic substitution of chloropyrimidines with amino‐containing chromophores is slow and often suffers from poor yields. In this study, a novel and simple method was developed for the synthesis of chloropyrimidine‐based reactive dye under microwave irradiation. In addition, the dye was also synthesised by conventional heating for comparison, which took both the reaction time and yield into account. The progress of the synthesis reactions concerned were monitored using capillary electrophoresis and the purity of the dye obtained was assessed by thin‐layer chromatography. The structure of the synthesised trichloropyrimidine dye was confirmed by Fourier Transform–infrared spectroscopy and elemental analysis. It was found that the reaction rate of the nucleophilic aromatic substitution carried out under microwave irradiation was 4‐fold faster than that carried out under conventional heating, although the enhancement in product yield was modest. These results suggest that microwave irradiation is an effective technique for the synthesis of chloropyrimidine‐based reactive dyes. The synthesised chloropyrimidine dye was formulated into an ink and applied onto a wool fabric by ink‐jet printing. The printed fabrics were steamed at 102°C for 5‐25 minutes at 5‐minute intervals. Good K/S and rate of dye fixation were obtained, both of which improved with increasing steaming time. The prints obtained exhibited reasonably good light and wash fastness properties.

Synthesis, stability and printing properties of a novel 2‐sulphophenoxy‐4‐chloro‐s‐triazine reactive dye for ink‐jet printing of wool

“…Analytics: micellar electrokinetic chromatography (MEKC) Migration time (MT) (4.55 minutes); purity (100%); R f (0.63); the chromophore 1 structure was confirmed by Fourier Transform–infrared (FTIR) (FTIR spectrum not shown here): N–H stretch, primary amine, 3328 cm ‐1 and 3227 cm −1 ; overtone or combinational bands, 2000‐1667 cm −1 ; C = C stretch, 1651, 1588 cm −1 ; N–H bending, 1625 cm −1 ; C = C ring stretch, 1555, 1492; azo group stretch, 1414 cm −1 ; C–N stretch (primary amine), 1247 cm −1 ; sulphonate salts, 1176 cm −1 ; in‐plane C–H bend, 1037 cm −1 ; broad, N–H wag, 881 cm −1 ; out‐of‐plane aromatic C–H bend, 809, 763 cm −1 ; CH 3 rock, 727 cm −1 . Elemental analysis, found: C, 41.98%; H, 3.03%; N, 8.59%; calculated for C 17 H 13 N 3 Na 2 O 6 S 2 .…”

“…The raw data were analysed using OriginPro 9.0.0. Elemental analysis of synthesised dyes for carbon, hydrogen and nitrogen was performed using a FlashEA 1112 analyser from Thermo Scientific …”

“…The inks were formulated using the following composition in deionised water: 40 g/dm 3 of synthesised yellow dye 1a or 1b , 20 g/dm 3 of 2‐pyrrolidone, 300 g/dm 3 of N‐methylmorpholine N‐oxide, 25 g/dm 3 of propan‐2‐ol and 10 g/dm 3 of polysorbate 20. The formulated inks were placed inside an ultrasonic water bath for 10 minutes then filtered using a 1 μm filter prior to use …”

“…The dye fixation percentage was determined using a Perkin Elmer Lambda 40 ultraviolet‐visible spectrophotometer to calculate the dye concentration in the various wash‐off solutions according to the procedure described previously …”

“…Light fastness and wash fastness tests were carried out according to BS EN ISO 105‐B02 (Method 3) and BS EN ISO 105‐C06:2010 (A1S) …”