Modification of cellulose with N-(2-chloroethyl)diethylamine hydrochloride: mechanism of improved dyeability with 5-chloro-2,4-difluoropyrimidinyl dyes

摘要

Monofluorotriazinyl and 5-chloro-2,4-difluoropyrimidinyl dyes were each reacted, in turn, with trimethyl-and triethyl-amine in aqueous solution. Tri methylamine was quaternised by both the fluoroheterocyclic reactive dyes, In the case of the chlorodifluoropyrimidinyl dye, NMR spectroscopy showed that displacement of the C-2 fluorine atom had occurred. Triethylamine, on the other hand, failed to react with either fluoroheterocycle, strongly suggesting that the covalent bond formation reaction of DEAE-cotton, with a 5-chloro-2,4-difluoropyrimidinyf dye under neutral conditions, does not involve initial quaternisation. A mechanism involving the deprotonation of the cellulose hydroxy groups, catalysed by the basic groups in DEAE-cotton, is proposed.