Deaggregation of benzimidazolone azo dyes

Synthesis and spectroscopic properties of novel phthalimide‐derived monoazo disperse dyes containing ester groups

“…Phthalimidylazo disperse dyes first appeared as the subject of patents over 30 years ago [18,19] and have also formed the basis for claims over the last few years [20–22] concerning good fastness and dyeability on polyester. While industry has exploited their chemistry commercially [23], little has appeared in the academic literature concerning their colour and application properties and that which has been published features examples with relatively simple structures [24–27].…”

Novel symmetrical and asymmetrical disaryl hydrazono sulphur-containing direct dyes as possible alternatives for benzidine-based dyestuffs

“…Unlike other dyes that accommodate additional o-sulphonic or carboxylic groups and suffer lower substantivity behavior, as a result of deformation of the dye molecules due to the vicinity of the previous group to an azo function [2], the hitherto synthesized highly colored products, being substituted with additional p-sulphonic acid groups, exhibited high substantivity and preliminary good light and washing fastness and thus might fully satisfy all the requirements for a satisfactory replacement of the harmful benzidine-based dyes. Detailed study for the dyeing performance, all-round fastness properties and evaluation of applying Fenton oxidation process [18] (as simple oxidation technology) for decomposition and removal of the residual of these dyes from dyeing baths, are for the time being, under investigation and will be the subject of the forthcoming communication.…”

“…The problem of replacing benzidine dyes has not been fully resolved, although a number of approaches have been made, based on two concepts. The first consists of the use of other classes of dyes for dyeing purposes, and the second approach involves the use of other diamines, i.e., diaminostilbene disulphonic acid [1] and diaminodiphenylaminesulphonic acid [2] in the dye synthesis. The first solution does not usually ensure obtaining all the hues possible from disaryl azo benzidine-based dyestuffs; it is more expensive, and often requires alternative dyeing technology.…”

“…The produced dyes, having their azo function attached to aliphatic side chain and accommodating solubilizing functions (sulphonic and sulphonamide moieties), are likely to undergo simple oxidation and/or hydrolysis to soluble metabolites, thus ensure lack of carcinogenicity [2] and in turn satisfy the basic requirements for a satisfactory replacement of the prohibited benzidine-based dyes.…”

Reactive dyes containing a benzimidazolone residue

“…An especially effective way of raising the substantivity was obtained by introducing a benzimidazolone residue into the dye molecules. It has been shown that the high substantivity of dyes containing a cyclic amide system is caused by the aggregation of the dye in solution, and on the fibre (3), as well as by the possibility of its disaggregation at elevated temperatures [8]. Our earlier attempts at increasing the fixation ratio of reactive dyes by increasing their substantivity through the building into their molecules of the benzimidazolone system proved to be ineffective; these results were not published [9].…”