John A Taylor

Monoazo disperse dyes: Part 1: Synthesis, spectroscopic studies and technical evaluation of monoazo disperse dyes derived from 2-aminothiazoles

Novel disperse dyes have been prepared from thiazolyl diazonium salts and coupling components based on m-aminoacetanilide derivatives. Depending upon various substituents incorporated into the chromophore, absorption maxima varied from 495 to 591 nm in various organic solvents. These dyes were chromophorically strong as evidenced both by molar extinction coefficient in solvent and by strength and build up on polyester.

A chemometric approach to understanding the bioelimination of anionic, water-soluble dyes by a biomass using empirical and semi-empirical molecular descriptors.

Single correlation and multiple linear regression analyses have been applied to understand the bioelimination of 103 anionic, water-soluble dyes by a biomass at a wastewater treatment works. The chemometric approach highlighted that anionic, water-soluble dyes with larger molecular size/ionic charge ratios and containing more primary aromatic amines and unsulphonated naphthalene nuclei and fewer aliphatic alcohol groups had superior levels of bioelimination.

The dyeing of cotton with hetero bi-functional reactive dyes containing both a monochlorotriazinyl and a chloroacetylamino reactive group

Water-soluble reactive dyes incorporating both a chloroacetylamino group and a monochlorotriazinyl group have been prepared. Under the alkaline application conditions employed, little or no additional fixation, via the desired nucleophilic displacement of chloride from the chloroacetylamino group, by cellulosate, was observed. The principal reaction was amide hydrolysis.

The dyeing performance on cotton of reactive dyes containing the α-bromoacrylamido group

Three reactive dyes containing the α-bromoacrylamido group have been synthesised and their performance assessed for the exhaust dyeing of cotton. The results indicate that, when situated in the appropriate electronic environment in the dyestuff molecule, this reactive grouping is compatible with the sulphatoethylsulphonyl (vinylsulphonyl) group in delivering warm dyeing (60°C) characteristics.

Synthesis and application of disperse dyes based on 1,4-bis(benzothiazol-2-yl)benzene to polyethylene terephthalate

Abstract Two novel water-insoluble dyes based on the 1,4-bis(benzothiazol-2-yl)benzene chromophore have been synthesised and applied to polyethylene terephthalate (PET) by exhaust dyeing. The dyes exhibited high levels of heat and wet-fastness but light fastness was very poor.

Interaction of oxidative bleach containing detergents with dyes. Part 1: Preparation and resistance of 1-amino-2-arylazonaphthalene-4-sulphonic acid dyes to hydrogen peroxide and m-chloroperbenzoic acid

A series of red water soluble azo dyes were prepared by coupling variously substituted phenyldiazonium salts onto 1-aminonaphthalene-4-sulphonic acid. In order to mimic the conditions experienced during domestic laundering, in presence of an oxidative-bleach containing detergent, the dyes were then subjected, separately, to treatment with m-chloroperbenzoic acid and with hydrogen peroxide. Experiments were conducted under alkaline conditions (pH 9.8) and pseudo first order rate constants were determined for dye destruction. The m-chloroperbenzoic acid was much more effective than hydrogen peroxide in bringing about loss of colour. The introduction of electron donating groups into the diazo component of the dyestuff, which would be expected to lead to an increased propensity to undergo attack by electrophilic species, resulted in increased levels of bleaching by the peracid. Additionally reduction in pH caused an increase in the rate of bleaching in presence of peracid, the rate increasing approximately tenfold per unit drop in pH. These observations are consistent with attack by m-chloroperbenzoic acid, a highly electrophilic species, rather than m-chloroperbenzoate (the major species present at pH 9.8).