Basic blue dyes

In the ketone method, the central carbon atom is derived from phosgene (qv). A diarylketone is prepared from phosgene and a tertiary arylamine and then condenses with another mole of a tertiary arylamine (same or different) in the presence of phosphoms oxychloride or zinc chloride. The dye is produced directly without an oxidation step. Thus, ethyl violet [2390-59-2] Cl Basic Violet 4 (15), is prepared from 4,4 -bis(diethylamino)benzophenone with diethylaruline in the presence of phosphoms oxychloride. This reaction is very useful for the preparation of unsymmetrical dyes. Condensation of 4,4 -bis(dimethylamino)benzophenone [90-94-8] (Michler s ketone) with AJ-phenjl-l-naphthylamine gives the Victoria Blue B [2580-56-5] Cl Basic Blue 26, which is used for coloring paper and producing ballpoint pen pastes and inks. 

Methylene Blue [61-73-4] CI Basic Blue 9 (CI 52015), (26), is the classic thiazine dye still in use today. This dye was first reported in 1876 (1). 

So-called delocalized cationic azo dyes are another type ia which the positive charge is delocalized (or distributed) across the dye cation. Basic Blue 54 (132) (2-amiao-6-methoxybenzothiazole coupled to /V, /V-dimethy1 ani1 ine and then quarternized with dimethyl sulfate) is an example of this class which can also be considered as a diazamethine dye. 

Another bright blue dye from diazotized 2-amiao-6-methoxybenzothiazole [1747-60-0] by azo coupling, eg, with 2(/V-ethy1ani1ino)ethano1 is Basacryl Blue X-3GL [12270-13-2] (133) (Cl Basic Blue 41 Cl 1110S). After couphng, the water-iusoluble dye is methylated at the thiazole nitrogen. 

The Cl name for a dye is derived from the appHcation class to which the dye belongs, the color or hue of the dye, and a sequential number, eg. Cl Acid Yellow 3, Cl Acid Red 266, Cl Basic Blue 41, and Cl Vat Black 7. A five digit Cl number is assigned to a dye when its chemical stmcture has been made known by the manufacturer. The following example illustrates these points, where CA indicates Chemicalj bstracts and Cl Colourindex. 

Benzoyl leuco Methylene Blue (1), which is a phenothiazine leuco dye, has been known since 1900. The material was developed to extend the range of hues and colors obtainable in such applications as pressure-sensitive carbonless paper and to complement other classes of leuco dyes such as triarylmethanes, crystal violet lactone, and fluorans. Benzoyl leuco Basic Blue 3 (2), which is a phenoxazine leuco dye, is a more recent development. 

The purple phenoxazone 36 is obtained by alkaline hydrolysis of Basic Blue 3.14 The benzophenoxazone 38 is obtained by coupling of 2-nitroso-5-diethylaminophenol with a-naphthol.14 The leucos 37 and 34 are obtained by refluxing the corresponding dyes with zinc powder in acid anhydride. 

Leuco Methylene Blue, Basic Blue 3, or phenazine dyes are capped with a dye bearing acid chloride or chlorocarbonyl functionality. Normal procedures employed for the synthesis of benzoyl leuco Methylene Blue can be utilized except that a dye chloroformate (69) replaces the benzoyl chloride. 

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 ... 

Continuous culture of immobilized P. chrysosporium on PuF was studied for decolorization of 4 different azo dyes [57]. Acid Black 1, Basic Blue 41, Reactive Black 5, and Reactive Orange 16 (R016) were effectively decolorized depending on the dye concentration. 

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). 

The thiazole ring system is found in many types of dye. Thiazole-containing sulphur dyes and primuline were considered in section 6.4-2. Quaternised dehydrothio-p-toluidine 6.133 is available as Cl Basic Yellow 1 (6.152). Other derivatives of this intermediate are used as direct dyes, such as Cl Direct Yellow 8 (4-58). The benzothiazole ring appears in various azo disperse dyes [14], quatemisation of which gives useful cationic dyes, an important example being Cl Basic Blue 41 (4.99). Another example containing a quaternised thiazole ring is Cl Basic Red 29 (4-102). 

Bindschedler s Green (6.204) can be made by condensing p-nitroso-N,N-dimethylaniline with N,N- dimethyl aniline. A similar condensation with 2-naphthol gives Meldola s Blue (6.209 Cl Basic Blue 6), the first oxazine dye, discovered in 1879. The symmetrical Cl Basic Blue 3 (6.210) is of more commercial significance. It is synthesised by nitrosation of N,N-diethybrn-anisidine followed by condensation with N,N-diethybm-aminophenol, and is used for dyeing acrylic fibres. This dye is now classified by ETAD as toxic [73]. 

The adsorption of textile dyes on natural sorbents was investigated by various HPLC methods. The chemical structures and calculated molecular areas of the dyes are depicted in Fig. 3.83. Because of their different chemical structures and retention characteristics, the dyes were separated in different columns with different mobile phases. Basic blue 41 (BB41) was determined in an octylsilica column (75 X 4.6 mm i.d.). The mobile phase consisted of methanol-KH2P04-Na2HP04 buffer (pH = 5) in volume ratio 1 1. Acid blue... 

Nonchelating dyes include basic triphenylmethane dyes (e.g., Brilliant Green, Malachite Green, Crystal Violet), xanthene dyes (e.g., Rhodamine B, Rhodamine 6G), azine dyes (e.g., Methylene Blue), and acid dyes (e.g., Eosin, Erythrosin). These are intensely colored and when paired with an oppositely charged analyte ion lead to high sensitivities. 

Figure 9. Structures of azo dyes acid green 25 (AG25), basic blue 9 (BB9), direct red 23 (DR23), acid orange 7 (A07) and amaranth (Am).

Awad, HS Abo Galwa N. Electrochemical degradation of Acid Blue and Basic Brown dyes on Pb/Pb02 electrode in the presence of different conductive electrolyte and effect of various operating factors. Chemosphere, 2005 61, 1327-1335. 

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). 

The delocalised charged dyes are dominated by cyanine dyes, exemplified by the azacarbocyanine Cl Basic Yellow 11 (2.27), the diazacarbocyanine Cl Basic Yellow 28 (2.30) and the diazahemicyanine Cl Basic Blue 41 (2.49). Where necessary quatemisation is carried out as a post colour forming reaction. Other structural types include oxazines, thiazines and triphenyhnethane dyes. 

Dyes with 2-amino-6-methoxybenzothiazole as diazo component are of industrial importance because their alkylated products dye polyacrylonitrile in clear, very lightfast, blue shades. With AfJV-dim ethyl aniline as coupling component, C.I. Basic Blue 54, 11052 [1500-59-6] is obtained. 

With butylcyanoethylaniline a blue dye is obtained that produces very steam-fast dyeings on polyacrylonitrile [76], The dyes with jV-methyldiphcnylaminc as coupling component dye polyacrylonitrile in greenish-blue shades. C.I. Basic Blue 41, 11105 [12270-13-2], for instance,... 

Attractive lightfast turquoise shades can be obtained witb Cu phthalocya-nines. Although these molecules are planar, they are insufficiently substantive in sulfited form so that the dyeings must be post treated with a fixative. By introducing cationic groups, e.g., by treatment with chlorosulfonic acid and subsequent amidation (26), very good affinity to paper is obtained, e.g., C.I. Basic Blue 140, [61724-62-7]. 

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