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An investigation into the in situ preparation of hetero bifunctional monochlorotriazinyl-vinyl sulphone reactive dyes for cotton.

Sumifix Supra dyes developed by Sumitomo showed minimal sensitivity to changes in electrolyte, alkali, liquor and exhibit high fixation over a range of processing conditions as compared with homobifunctional dyes (Aspland, 1993; Abeta et al., 1984; Fujioka and Abeta, 1982). These hetero bifunctional reactive dyes are also robust to changes in processing conditions such as application temperature (Hunter and Renfrew, 1999). Earlier it was assumed that under strict neutral conditions and at constant temperature the major reaction would be the condensation reaction of dichlorotriazinyl dyes with aminophenyl-P-sulphatoethyl sulphone not the hydrolysis of dichlorotriazinyl dyes or of vinyl sulphone group with water (Lewis and Loan, 2007; Weber and Vicki, 1993). An attempt was made in this research work to condense dichlorotriazine dyes with aminophenyl-P-sulphatoethyl sulphone in the dye bath under neutral conditions prior to addition of salt and alkali required for the (neutral) exhaustion and (alkaline) fixation stages.

Dichlorotriazinyl dyes Cl Reactive Orange 86, Cl Reactive Red 11, Cl Reactive Blue 168 and dyes of Sumifix Supra type Cl Reactive Yellow 145, Cl Reactive Red 195, Cl Reactive Blue 221 were available commercially. All other chemicals used in this study were of general laboratory grade purchased from Aldrich or Merck. Samples of para and meta aminophenyl-Psulphatoethyl sulphone were generously provided by BASF. The strength of dyestuff samples were estimated from the ratio of its actual molecular weight (MW) to its effective molecular weight (Mole In) estimated by titanous chloride titration method (Murtagh, 2004) and is given in Table 1.

Experimental results suggested that for in situ application of dichlorotriazine dye and sulphatoethyl sulphones agents, temperature of dye bath should beat70 [degree]C, and pH should be 6.0-6.5 using phosphate buffer with reaction time of 1 h, however, reaction period of 2 and 4 h were also measured. Each dye was applied to bleach unmercerised woven cotton at five depths, viz. 1,2,4, 6 and 9% dye o.m.f. at 60 [degree]C and liquor ratio 10:1, using the quantities of Glauber's salt (exhaustion for 30 min) and soda ash (fixation for 60 min) as shown in Table 2. After dyeing, the fabric was rinsed with cold and hot water before soaping at boil for 10 min and finally rinsed with cold water and air dried at room temperature. Colorimetric properties of dyeing were determined using a Spectraflash 600 spectrophotometre (D65 illumination, 10[degree] observer). To facilitate the comparison of the build-up properties of these dyes, k/s values versus dye concentrations in millimoles per 100g of fabric were plotted.

[FIGURE 1 OMITTED]

Dyeing results of Cl Reactive Orange 86 with PABSES (Fig. 1) showed that the depths of shade under these conditions are far inferior to when PABSES is present, supporting the premise that a Sumifix Supra type of heterobifunctional dye is indeed formed in the dye bath. Dyeing results appeared to indicate partial conversions of dichlorotriazine to a monochlorotriazine-vinyl sulphone mixed reactive system. Results for meta isomer (MABSES) are given in Fig. 2 and shows that significant conversion to mixed bifunctional dye had occurred within two hours but again build up was inferior on an equimolar basis to CI Reactive Yellow 11.

[FIGURE 2 OMITTED]

Results for both isomers (PABSES and MABSES) with CI Reactive Red 11 are depicted in Fig. 3-4 and shows that the best build up was obtained when dichlorotriazine and amine were reacted at 70 [degree]C for 2 h prior to addition of salt and alkali. Interestingly, with Cl Reactive Red 11, the para isomer performed significantly better than the meta isomer.

CI Reactive Blue 168 showed mixed results which are shown in Fig. 5-6. In some cases build-up was almost comparable to CI Reactive Blue 168 (commercial counterpart). However, in all cases build-up tailed of f above 4% depth of dye shade.

[FIGURE 3 OMITTED]

[FIGURE 4 OMITTED]

[FIGURE 5 OMITTED]

[FIGURE 6 OMITTED]

Dyeing results when compared with commercial Sumifix Supra dyes of similar shades were inferior in performance. Meta isomer of aminophenyl-[beta]-sulphatoethyl sulphone appeared to be more effective than the para isomer. This probably reflects more nucleophilic character of the former isomer (Sheng, 1998). The falling-off of the build-up properties of some of the dyes at darker shades may be due to blocking effect.

References

Abeta, S., Yoshida, T., Imada, K. 1984. Problems and progress in reactive dyes. American Dyestuff Reporter, 73: 26-49.

Aspland, J.R. 1993. A Series on dyeing, Chapter 15, Colour, colour measurement and control. Journal of the American Association of Textile Chemists and Colourists, 25: 34-42.

Fujioka, S., Abeta, S. 1982. Development of novel reactive dyes with a mixed bifunctional reactive system. Dyes andPigments, 3: 281-294.

Renfrew, A.H.M. 1999. Reactive Dyes for Textile Fibres. 224 pp., Society of Dyers and Colourists, Bradford, UK.

Lewis, D.M., Loan, T.T.V. 2007. Dyeing cotton with reactive dyes under neutral conditions. Coloration Technology, 123: 306-311.

Sheng, Y., Zhenghua, Z. 1998. Kinetic study of reaction of vinylsulfonyl aniline and dichlorotriazinyl group. Dyes andPigments, 38: 137-146.

Taylor, J.A., Murtagh, V. 2004. A simple titrimetric method for the estimation of reactive dye fixation on cellulosic fabrics. Dyes and Pigments, 63: 17-22.

Weber, E.J., Stickney, V.C. 1993. Hydrolysis kinetics of reactiveblue 19-vinylsulfone. Water Research, 27: 63-67.

Khalid Pasha (a) * and John Anthony Taylor (b)

(a) Textile Engineering Department, NED University of Engineering and Technology, Karachi, Pakistan

(b) Colour Synthesis Solution Ltd., Hexagon Tower, Manchester M9 8ZS, UK

(received June 3, 2014; revised March 3, 2015; accepted April 1, 2015)

*Author for correspondence; E-mail: drkpasha@hotmail.com
Table 1. Effective dye strength

Dyes                      Moles In

CI Reactive Orange 86     1792
CI Reactive Red 11        1482
CI Reactive Blue 168      2919
CI Reactive Yellow 145    1472
CI Reactive Red 195       1705
CI Reactive Blue 221      3310

Table 2. Amount of salt and alkali used

               Sodium sulphate       Sodium carbonate
               (g/L)                 (g/L)

Shades % dye   Procion    Sumifix    Procion    Sumifix
(o.m.f)        MX         supra      MX         supra

1&2            35         35         10         20
4              45         50         15         20
6&9            55         50         20         20
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Title Annotation:Short Communication
Author:Pasha, Khalid; Taylor, John Anthony
Publication:Pakistan Journal of Scientific and Industrial Research Series A: Physical Sciences
Article Type:Report
Date:Jan 1, 2016
Words:1008
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