Basic dyes anthraquinone

Dyes, Dye Intermediates, and Naphthalene. Several thousand different synthetic dyes are known, having a total worldwide consumption of 298 million kg/yr (see Dyes AND dye intermediates). Many dyes contain some form of sulfonate as —SO H, —SO Na, or —SO2NH2. Acid dyes, solvent dyes, basic dyes, disperse dyes, fiber-reactive dyes, and vat dyes can have one or more sulfonic acid groups incorporated into their molecular stmcture. The raw materials used for the manufacture of dyes are mainly aromatic hydrocarbons (67—74) and include ben2ene, toluene, naphthalene, anthracene, pyrene, phenol (qv), pyridine, and carba2ole. Anthraquinone sulfonic acid is an important dye intermediate and is prepared by sulfonation of anthraquinone using sulfur trioxide and sulfuric acid. 

In the 1950s acid dyes were successively developed to dye nylon carpet with excellent fastness and uniform leveling. Development of polyacrylonitrile fiber stimulated the invention of anthraquinone basic dyes, modified disperse dyes in which quaternary ammonium groups are introduced. 

Most of these products are azo or anthraquinone types, often with a localised quaternary ammonium group isolated from the chromogen by a saturated alkyl chain, as in Cl Basic Red 18 (1.52). Such products often exhibit higher light fastness than the traditional delocalised types. Improved azomethine, methine and polymethine basic dyes of good light fastness are also available. In contrast to the more specialised traditional classes, the azo and methine dyes have contributed to the basic dye range across the entire spectrum of hues (see Table 1.6) and now account for a clear majority of all basic dyes listed in the Colour Index. 

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. 

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]. 

Most of the basic dyes used for the polyacrylonitriles belong to the more recently developed azo and anthraquinone groups, as well as the methines. An example of an azo dye is ... 

The anthraquinone vat dyes derived basically from anthraquinone, (3) ... 

It has been reported that y3-CD could improve the selectivity of the color reactions of various metal ions with triphenylmethane, xanthene acid dyes and some other coloring reagents. The effect of fi-CD on the association compound system of metal (Mo, Zn, Co)-thiocyanate basic dyes such as malachite green, crystal violet, rhodamine B, rhodamine 6G and butyhhodamine B, has been investigated and the result shows that /3-CD could contribute to a more sensitive and stable system which improve the solubility of the basic dyes and produce a favorable microenviromnent for the color reactions [63]. /3-CD could be employed to solubilize the 1,2-amino anthraquinone in water due to the formation of inclusion complex which acts as a ligand for metal ions could be used for the determination of palladium at trace levels by spectrophotometry. In the spectrophotometric determination of microamounts of Zn based on the Zn-dithizone color reaction, -CD could increase the apparent molar absorptivity at 538 nm by 8.37 times. In the presence of cr-CD, the determination sensitivity of copper in leaves based on the color reaction of Cu(II) and mesotetrakis (4-methoxy-3-sulfophenyl) porphyrin was enhanced by 50% in the spectrophotometric analysis [64,65]. 

Basic (or cationic) dyes They contain quaternary amine groups in their molecular structure. Examples of basic dyes are azo basic dyes (e.g. Basic Red 22) and cationic anthraquinone dyes (e.g. Basic Blue 47). Figure 4.3.3 shows the chemical structure of two of these semi-permanent dyes. 

Several basic chromophore stmctures have been proposed for this purpose. Anthraquinone dyes appear to be predominant since they have a wider color range, excellent photostabiHty, good solubiHty in Hquid crystal media, and very high order parameters. Typical basic stmctures of the three primary colors are illustrated in Figure 11. Some examples are given in Table 10. The appropriate combination of three primary colors gives a black display. 

Fig. 11. Basic stmctural concepts for the three primary color anthraquinone Hquid crystal dyes.

DC11 Malachite Green, Basic Blue efficiency (95-98%) achieved within 6 h for 100 mM Acid Blue 25 (anthraquinone dye), 4 h for 55 mM Malachite Green (triphenylmethane dye), and 2 h for 750 mM Basic Blue X-GRRL under anaerobic conditions ... 

Basic chrome sulfate, 6 543 Basic copper chromate, molecular formula, properties, and uses, 6 561t Basic detergents, 15 222 Basic (cationic) dyes, 9 217, 242-243 anthraquinone, 9 301 azo, 9 421 24 Basic dyestuffs, 9 224 Basic extractants, of rare-earth elements, 14 642... 

ANTHRAQUINONE ACID, DISPERSE, BASIC AND REACTIVE DYES... 

Some anthraquinone dyes with pendant cationic groups are used commercially on acrylic and modacrylic fibres [22]. Only two disclosed structures are included in the latest revision of the Colour Index, the dyes being the reddish blue Cl Basic Blue 47 (6.54) and the greenish blue Cl Basic Blue 22 (6.55). 

Anthraquinone acid, disperse, basic and reactive dyes 280 Polycyclic vat dyes 294 Indigoid and thioindigoid dyes 316 Sulphur and thiazole dyes 321 Diarylmethane and triarylmethane dyes 327 Miscellaneous colorants 344 References 353... 

The dyes bearing pendant cationic gronps are usually derived from azo or anthraquinone dyes. The azo dyes are normally made by coupling the diazo component onto a preformed cationic coupling component, exemplified by Cl Basic Blue 119 (2.46) from (2.44) and (2.45). Contrastingly, in anthraquinones the quatemisa-tion is usually carried as a post colour forming step, e.g. Cl Basic Blue 13 (2.48) from (2.47). 

Colouring matters which are neither acid nor basic are reduced and oxidised on the cotton itself. The resistance to reduction exhibited by certain azo-colouring matters, especially those formed directly on the fibre, is overcome by addition of very small quantities of suitable colouring matters or other reducing bodies, such as indulin scarlet, alizarin or anthia-quinone, which increase the activity of the hydrosulphite. The use of anthraquinone is preferred because it does not dye cotton, while addition of it in minimal quantity to the hydrosulphite solution and slight acidification with acetic acid yields a reagent (hydrosulphite B X) which causes reduction in every case. 

Acid, basic, and direct dyes are all ionic in nature. Acid dyes contain free acid groups which are ionized in the aqueous application medium (dyebath). They generally used to dye polyamine, wool, or silk and are primarily azo, anthraquinone, or triarylmethane structures. 

Basic (cationic) dyes contain cationic groups which are ionized in the dyebath. They are applied to acrylics, nylon, polyester, and paper and are most often azo, anthraquinone, triarylmethane, quinoline, thiazine, methine, oxazine, and acridine types. 

Reactive cotton, wool, silk, and nylon reactive site on dye reacts with functional group on fiber to bind dye covalently under influence of heat and pH (alkaline) azo, anthraquinone, phthalocyanine, formazan, oxazine, and basic... 

The introduction of auxochromes into the almost colorless anthraquinone permits the tailoring of compounds to cover nearly all shades of dye colors types and positions of the substituents in the molecule determine the hue. As a rule the bathochromic shift in simple anthraquinones increases with increasing basicity of the substituents. This generalization is clearly shown by the wavelengths of the longest wavelength absorption maximum of anthraquinones mono substituted in the 1-position [1] (Table 3.5) ... 

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