The reaction of monochlorotriazine (MCT) & Dichlorotriazine (DCT) with cellulose and water
The following diagram illustrates the reaction between the dye and water in the case of the "H" type dye (mono chloro triazine reactive dye)
Monochlorotriazine reaction with-
(A) Cellulose hydroxide (Cell-OH)
(B) Water(H2O)
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| Dyeing of Cotton Fabric with Reactive Dyes |
Explanation-
(A) Reaction with Cellulosic Hydroxide (Cell-OH):
(i) Resulting in Desirable compound
(B) Reaction with Water (H2O) :
(ii) Resultant in Undesirable compound
The reaction of the dye with Cellulose ions to give compound -Although undesirable, the reaction shown in
(ii) with water cannot be prevented even though it is desired. However,
the reactive dyes combine with Cellulose hundreds of times faster than they do with water.
Dichlorotriazine reaction with -
(A) Cellulose
(B) Water
The reactions are more complicated in the case of dichlorotriazine dyes (M type), as demonstrated below::
Reaction :
Both reactions of (DCT) Dichlorotriazine are shown above Dichlorotriazine (DCT) will form various compounds so, it's a bit complicated process with Dichlorotriazine.
Where For the easy representation of triazine ring is given by-
Only compounds leading to (iii) and (iv) are important as far as the fixation of the dyes to the fibre is anxious. The Cellulose fibre when dyed with dichlorotriazine dyestuff, contains a mix of (iii),(iv) and (v) and their proportion varies with the strategy of drying. In cold dyeing within the presence of mild alkali, most of the dye remains in form (iii), since the reactivity of the second chlorine atom is much reduced.
With a stronger alkali employed in cold dyeing, more cross-linkage takes place to supply a greater proportion of (v) but at higher temperatures (100°C), hydrolysis occurs giving rise to compound (vi) mainly.
The single linkages to Cellulose remaining in compound (vi) are proof against further Alkaline Hydrolysis but in some cases in danger of acid hydrolysis. In the actual dyeing operation, the second stage reaction of dichlorotriazine dyestuff could even be ignored.
The main objective of dyeing with reactive dyes is to induce the utmost fixation and minimum hydrolysis with water. The smaller the quantity of hydrolysed dye the simpler it'll be within the ultimate washing operation.
Questions -
- Describe The reaction of monochlorotriazine (MCT) with cellulose and water.
- Describe The reaction of Dichlorotriazine (DCT) with cellulose and water.
References
Ahmed, S. (2014, September 29). Reactive dyes - classification. TextileTuts. https://textiletuts.com/reactive-dyes/
Chakraborty, J. N. (2010). Waste-water problem in textile industry. In Fundamentals and Practices in Colouration of Textiles (pp. 381–408). Elsevier.
Clark, M. (2011). Handbook of textile and industrial dyeing: Principles, processes and types of dyes (Matthew Clark, Ed.). Woodhead Publishing.
No title. (n.d.). Acs.org. from https://cen.acs.org/articles/96/i29/new-textile-dyeing-methods-make.html
Patwary, E. M. Z. (2012, February 18). Reactive dyes. Textile Fashion Study; Engr. Mohammad Zillane Patwary. https://textilefashionstudy.com/reactive-dyes-definition-classification-properties-and-influencing-factors/
Sayed, A. (n.d.). Why reactive dye is so called? Blogspot.com. from https://textileapex.blogspot.com/2013/11/reactive-dye.html
(N.d.). Textilelearner.net. from https://textilelearner.net/reactive-dyes-classification-dyeing-mechanism/
What are Reactive Dyes? Types of Reactive Dyes. (n.d.). Meghmaniglobal.com. from https://www.meghmaniglobal.com/what-are-reactive-dyes-types-of-reactive-dyes/
Continue reading,
Part 2 Classification of Reactive dyes
Part 3 The reaction of MCT and DCT of reactive dyes
Part 4 General Factors affecting the results of reactive dyeing
Part 5 Reactive dyeing method - DCT
Part 6 Bifunctional systems of reactive dyes
Part 7 Development of reactive dyes
Part 8 Reactive dyes on Silk and nylon with their application
Part 9 Industrial applications of reactive dyes
Part 10 After treatment of reactive dyes
Writer - Rushikesh Patil (Textile Engineer)
