Anthraquinone, reactivity with

Many anthraquinone reactive and acid dyes are derived from bromamine acid. The bromine atom is replaced with appropriate amines in the presence of copper catalyst in water or water—alcohol mixtures in the presence of acid binding agents such as alkaU metal carbonate, bicarbonate, hydroxide, or acetate (Ullmaim condensation reaction). 

SuIfona.tlon, Sulfonation is a common reaction with dialkyl sulfates, either by slow decomposition on heating with the release of SO or by attack at the sulfur end of the O—S bond (63). Reaction products are usually the dimethyl ether, methanol, sulfonic acid, and methyl sulfonates, corresponding to both routes. Reactive aromatics are commonly those with higher reactivity to electrophilic substitution at temperatures > 100° C. Tn phenylamine, diphenylmethylamine, anisole, and diphenyl ether exhibit ring sulfonation at 150—160°C, 140°C, 155—160°C, and 180—190°C, respectively, but diphenyl ketone and benzyl methyl ether do not react up to 190°C. Diphenyl amine methylates and then sulfonates. Catalysis of sulfonation of anthraquinone by dimethyl sulfate occurs with thaHium(III) oxide or mercury(II) oxide at 170°C. Alkyl interchange also gives sulfation. 

Reactive dyes generally contain colored anthraquinones with various reactive groups attached to the nonchromophotic portions of the molecule. 

Efforts to raise the alpha-selectivity have been made. Thus nitration of anthraquinone using nitrogen dioxide and ozone has been reported (17). l-Amino-4-bromoanthraquinone-2-sulfonic acid (bromamine acid) [116-81 -4] (8) is the most important intermediate for manufacturing reactive and acid dyes. Bromamine acid is manufactured from l-aminoanthraquinone-2-sulfonic acid [83-62-5] (19) by bromination in aqueous medium (18—20), or in concentrated sulfuric acid (21). l-Aminoanthraquinone-2-sulfonic acid is prepared from l-aminoanthraquinone by sulfonation in an inert, high boiling point organic solvent (22), or in oleum with sodium sulfate (23). 

Green dyes are obtained by bridging an anthraquinone blue chromogen with a yeUow chromogen, as in the following reactive green (28) [72090-52-9] (14) or from phthalocyanine (7). 

Heavy metals are widely used as catalysts in the manufacture of anthraquinonoid dyes. Mercury is used when sulphonating anthraquinones and copper when reacting arylamines with bromoanthraquinones. Much effort has been devoted to minimising the trace metal content of such colorants and in effluents from dyemaking plants. Metal salts are used as reactants in dye synthesis, particularly in the ranges of premetallised acid, direct or reactive dyes, which usually contain copper, chromium, nickel or cobalt. These structures are described in detail in Chapter 5, where the implications in terms of environmental problems are also discussed. Certain basic dyes and stabilised azoic diazo components (Fast Salts) are marketed in the form of tetrachlorozincate complex salts. The environmental impact of the heavy metal salts used in dye application processes is dealt with in Volume 2. 

Two different chemical classes contribute to this sector. Initially it was entirely dominated by anthraquinone dyes typified by structure 7.102. The dye bases for attachment of haloheterocyclic (Z) systems are prepared by condensing bromamine acid (7.103) with various phenylenediamines. The outstandingly successful Cl Reactive Blue 19 (7.3 7) is the... 

The effect of this additive on the conventional dyeing of wool with the anthraquinone sulphatoethylsulphone dye Cl Reactive Blue 19 (7.37) was investigated. 

As noted in the Introduction sulfenic acids are generally unstable and reactive. A few, namely, anthraquinone-1-sulfenic acid [1], anthraquinone-l,4-di-sulfenic acid [2], and the sulfenic acid [3] (generated by thermolysis of sulfoxide [4]) have, however, been isolated as pure crystalline compounds (Bruice and Sayigh, 1959 Bruice and Markiw, 1957 Chou et al., 1974). Another sulfenic acid that appears to be of considerable stability is the pyrimidine derivative [5]. The silver salt of [5] was isolated by Pal et al. (1969) from the alkaline hydrolysis of the corresponding disulfide. The free sulfenic acid [5] was then liberated in solution by treating the silver salt with dilute aqueous hydrochloric acid and filtering off the silver chloride formed. Solutions... 

Quinones of the more reactive, polycyclic, aromatic systems can usually be obtained by direct oxidation, which is best carried out with chromium(vi) compounds under acidic conditions. In this way 1,4-naphthoquinone, 9,10-anthraquinone and 9,10-phenanthraquinone are prepared from naphthalene, anthracene and phenanthrene respectively (Expt 6.128). Also included in this section is the reduction of anthraquinone with tin and acid to give anthrone, probably by the sequence of steps formulated below. 

In a DTA study of 14 anthraquinone dyes, most had high flash points (225—335°C) and ignition points (320—375°C). Purpurin dianilide [107528-40-5] was exceptional with the much lower values of 110 and 155°C, respectively [1]. A similar study of indigo type dyes and vat solubilised modifications is reported. The basic dyes decompose over 350°C, destabilised to around 200°C for solubilised dyes. The relation between functional groups, structure and flammability is discussed [2]. Sulfonyl azides have been employed for attachment of reactive dyes, it is claimed they are safer used in supercritical carbon dioxide than in water [3]. 

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