FACTORS ASSOCIATED WITH FUNCTIONAL GROUP ATTACHMENT TO THE CHROMOGEN AND IMPORTANT REACTIVE SYSTEMS WITH TYPICAL BRAND NAME

Many reagents can be used to acylate cellulose when it is partially ionised under alkaline conditions but in the production of reactive dyes of commercial interest numerous factors other than the chemistry of such reactions have to be taken into account. Some of the most important are the following:

1. Economy – any reactive system selected as the basis of a range of dyes must enable them to be produced at acceptable cost.
2. Availability – the system selected must be free from patent restrictions, health hazards or other limitations to exploitation.
3. Facility – it must be possible to attach the reactive system to the dye chromophoric groupings readily in manufacture.
4. Storage stability – the dye containing the reactive groups must be stable to storage under ambient conditions.
5. Efficiency – the yield in manufacture of the reactive dye must be efficient and the dye fixation must be high under conventional conditions of application.
6. Bond stability – the dye–fibre bond must be reasonable stable under severe conditions of washing and durable finishing.

Only a few reactive systems (Table) have met these requirements sufficiently well to become commercially established in a significant segment of the market for reactive dyes on cellulosic fibres. In addition to these important types, several others have been marketed as alternative ranges that have failed to maintain a foothold in the market-place, or as individual members of established ranges where they show reactivity characteristics similar to one of the more important reactive systems. These systems of relatively minor significance include: 2-alkoxy- 4-chloro-s-triazine, 2,4-dichloropyrimidine-5-carbonylamino, 5-cyano-2,4-dichloropyrimidine, 5-chloro-2-fluoro-4-methylpyrimidine, 5-chloro-4-methyl-2- methylsulphonylpyrimidine, 1,4-dichloropyridazine-5-carbonylamino, 2-chlorobenzothiazole- 6-sulphonylamino, sulphatoethylsulphamoyl and sulphatopropionylamino.

During the early years of development of reactive dyes it was soon recognised that the important reactive systems could be classified into two distinct categories, depending on the mechanism of formation of the dye–fibre bond and the stability of this bond to subsequent treatments [8,10]. Those based on nitrogen-containing

System	Typical brand name
Monofunctional
Dichlorotriazine	Procion MX (Zeneca)
Aminochlorotriazine	Procion H (Zeneca)
Aminofluorotriazine	Cibacron F (CGY)
Trichloropyrimidine	Drimarene X (S)
Chlorodifluoropyrimidine	Drimarene K (S)
Dichloroquinoxaline	Levafix E (BAY)
Sulphatoethylsulphone	Remazol (HOE)
Sulphatoethylsulphonamide	Remazol D (HOE)
Bifunctional
Bis(aminochlorotriazine)	Procion H-E (Zeneca)
Bis(aminonicotinotriazine)	Kayacelon React (KYK)
Aminochlorotriazine-sulphatoethylsulphone	Sumifix Supra (NSK)
Aminofluorotriazine-sulphatoethylsulphone	Cibacron C (CGY)