Azide Reactive Dyes

Abstract

Reactive dyes containing a sulphonylazide group can undergo fixation on nylon substrates by two different mechanisms. Under aqueous dyeing conditions, at or below 120d̀ C, the free amino end‐groups of the polymer attack the sulphonylazide group with displacement of azide ion, and results in attachment of the dye to the substrate by a sulphonamide linkage. In contrast, if the dyed substrate is subjected to dry heat fixation at 170d̀ C, the azide group decomposes to a sulphonylnitrene species which undergoes insertion into C‐H bonds of the polymer. The dye is again attached by a sulphonamide bridge, but in this case the amount of dye that can be fixed is independent of the amino end‐group content of the polymer.

Azides Part II — Mechanism of Fixation of Sulphonazido Dyes on Polyester Fibre*

“…As expected, the reaction gave dimethyl 2-p-(2'-hydroxy-5'-methylphenylazo)-benzenesulphonamidoterephthalate (111) and 2,s-dicarbomethoxy-I -p- The n.m.r. 3. Aromatic protons appeared in the region 7.1-8.…”

“…The protons of the azepine ring overlapped with the aromatic protons and appeared as multiplets in the region 6.2-8. 3.…”

“…Recently, Griffiths and McDarmaid [3] have studied the mechanism of fixation of sulphonazido disperse dyes on nylon 6 and the use of azido dyes for transfer printing [4]. They chose the 2-hydroxy-5-methyl-4'-sulphonazidoazobenzene (I) as a model.…”

The Influence of Polymer Morphology on the Dyeing Properties of Synthetic Fibres

“…An interesting mechanism of dye interaction has been observed with sulphonazide disperse dyes [37]. From an aqueous dyebath at or below 120"C, the dye is bound at the free amino end groups (AEG) of the polymer, which are sufficiently nucleophilic to displace the a i d e ion to form a sulphonamide covalent link.…”

Azides Part I ‐ Reactive Dyes Containing the Azido Group for Synthetic‐polymer Fibres*

“…After preliminary findings on the synthesis and application to synthetic-polymer fibres of dyes containing reactive azido groups [ l ] , the mechanism of fixation of sulphonylazido disperse dyes on nylon 6 [2] and their transfer-printing properties on nylon 6.6 [3] were reported. The present paper reports work on reactive dyes containing sulphonylazido, carbonylazido, arylazido and azidoacetamido groups for synthetic-polymer fibres (polyester, nylon and cellulose acetate).…”