Violet dye

Many hydrazones and azines are colored and useful as dyestuffs. Examples are 2-hydroxynaphthazine, a yellow fluorescent dye (Lumogen LT Bright Yellow), and the pyridon—azino—quinone class of red-violet dyes. Numerous hydrazine derivatives are antioxidants and stabilizers by virtue of their reducing and chelating powers. 

Bromide ndIodide. The spectrophotometric determination of trace bromide concentration is based on the bromide catalysis of iodine oxidation to iodate by permanganate in acidic solution. Iodide can also be measured spectrophotometricaHy by selective oxidation to iodine by potassium peroxymonosulfate (KHSO ). The iodine reacts with colorless leucocrystal violet to produce the highly colored leucocrystal violet dye. Greater than 200 mg/L of chloride interferes with the color development. Trace concentrations of iodide are determined by its abiUty to cataly2e ceric ion reduction by arsenous acid. The reduction reaction is stopped at a specific time by the addition of ferrous ammonium sulfate. The ferrous ion is oxidi2ed to ferric ion, which then reacts with thiocyanate to produce a deep red complex. 

Many red dyes are based on H-acid [90-20-0] (11), eg, Reactive Reds 2, 24, and 218. Others are substituted phenyl and naphthyl or metallised systems (7) (Table 2). Violet dyes are also metallised monoaso dyes (7). 

Pigments or dyes may be added at this stage and where clear water-white sheet is required a small amount of a soluble violet dye is added to offset the faintly yellow colour of the natural mix. Stabilisers such as zinc oxide, zinc acetate or urea may be added to prevent the composition from developing acidity. 

The decolorization of crystal violet dye by reaction with sodium hydroxide is a convenient means for studying mixing effects in continuous-flow reactors. The reaction is... 

Treatment of the complex with further amine produced the violet dyes. The importance of this complex in the mechanism is suggested by the inability of cupric acetate, nitrate or sulphate to achieve the oxidation. 

Going, R. E., Massler, M. Dute, H. L. (1960). Marginal penetration of dental restorations as studied by crystal violet dye and Journal of the American Dental Association, 61, 285-300. 

Hexa(hydroxyethyl)pararosaniline nitrile has been used in a chemical radiochromic dosimeter.130 Ferricyanide oxidation of leuco Crystal Violet to Crystal Violet dye finds use in detection of various heavy metals131 at trace quantities. Oxidation of leuco triphenylmethanes by chloramine-T is catalyzed by iodide and therefore is used for detection of iodide.132 On the other hand, the inhibition of the catalytic effect of iodide by some ions can be used for determining traces of Ag(I), Hg(II), Pd(II). In addition, the triphenylmethane leuco dyes, phenolphthalein or phenol red are used extensively as indicators in calorimetric and titrimetric determinations. 

When all the violet dye is off the column, begin to collect and evaporate 10-ml. fractions. Two or three fractions, which on evaporation yield little or no residue, will precede the appearance of the 7-benzene hexachloride. Continue to collect 10-ml. fractions and evaporate until no more 7-benzene hexachloride is obtained. Stop the column operation, dissolve the several 7-benzene hexachloride residues with a minimum quantity of n-hexane, and pour into a tared 125-ml. Erlenmeyer flask. Evaporate under vacuum, using the solvent evaporator, at 60° and finally at room temperature for 5 minutes with a high vacuum pump. Release the vacuum, wipe the flask with a clean, moist towel, and weigh after allowing the flask to come to equilibrium near the balance. Calculate the percentage of 7-benzene hexachloride in the original sample. 

The natural dye was extracted by immersion of fresh Morns nigra (black mulberry) in ethanol for several hours. The pure violet dye extract, a blend of p-carotene and Morus nigra, and a composite blend of chlorophyll A and B, carminic acid, trans-P-carotene, and Morus nigra extracts (hereafter called Mix) were deposited on Ti02. 

Direct vacuum gauges, 20 657 Direct vasodilators, antihypertensive agents, 5 165-166 Direct violet dyes, 9 406... 

Monoarylation of l-amino-4-hydroxyanthraquinone (6.39 X = OH) results in violet dyes such as Cl Disperse Violet 27 (6.44 R = H) and the bluish violet Cl Disperse Blue 72 (6.44 R = CH3) the latter dye is also important as Cl Solvent Violet 13. Chlorination of 1,4-diaminoanthraquinone with sulphuryl chloride gives the 2,3-dichloro derivative (Cl Disperse Violet 28), which on condensation with phenol yields Cl Disperse Violet 26 (6.45). Monoaryl or dialkyl derivatives of 1,4-diaminoanthraquinone (6.19 Cl Disperse Violet 1) are blue. Typical examples include Cl Disperse Blue 19 (6.46) and Cl Disperse Blue 23 (6.47). 

Fig. 3.99. Examples of the evolution of the chromatographic peak areas corresponding to the dye metabolites during SBR 1 cycles in periods 2 (a) and 3 (b). Metabolites 1 ( ) and 3 ( ) correspond to the benzene-based and naphtalene-based amines, respectively. Metabolite 2 (o) is apparently in equilibrium with metabolite 1. The violet dye concentrations calculated form spectrophotometric analysis ( ) are also presented. Reprinted with permission from N. D. Lourenco et al. [156],...

In principle, the same photoexcited reactant, if it is liable both to oxidation and reduction, can inject both electrons (into an -type semiconductor) and holes (into a p-type semiconductor). Such a material is, for example, the crystal-violet dye. Figure 25 shows the spectra of cathodic photocurrent iph at p-type gallium phosphide and anodic photocurrent at n-type zinc oxide both in a solution, which does not absorb light (dashed lines), and in the presence of crystal violet the absorption spectrum of the latter is also shown for comparison. 

Fig. 25. Absorption spectrum of the crystal-violet dye (a) and the spectra of anodic photocurrent at an electrode of n-type ZnO (b) and of cathodic photocurrent at an electrode of p-type GaP (c) in the presence of crystal violet (in pA/cm2). The dashed line is the photocurrent in the absence of the dye. [From Gerischer (1977b).]...

Pyrazolinones belong to the heterocyclic class of coupler and are widely used the sulfonamide (124) is representative of this type (51USP2537098). Substituted thiophenes (125) (58GEP1025265) and hydroxypyridones (126) (47USP2431190) are couplers which form blue-violet dyes resistant to light. Pyranones (127), analogous to the latter, have also been used (51USP2542849). 

Proton abstraction from the neutral imine gives its conjugate base, which is a violet dye. 

Chaube et al. [47] investigated the determination of ultratrace concentrations of nitrite in sulfuric acid extracts in soil. In their method, the nitrite is used to diazotise o-nitroaniline and the o-nitrophenyldiazonium chloride produced is coupled with N-naphlhylcthylcncdiaminc hydrochloride. The red-violet dye produced is extracted into isoamyl alcohol and evaluated spectrophotometrically at 545 nm. Beer s law is obeyed in the range 0.1 to 0.6 mg nitrate per litre of solution. 

Such anionic surfactants that form ion pairs with methylene blue and that are extractable with chloroform are known as Methylene Blue Active Substances (MBAS). Other cationic dyes, such as crystal violet dye, may be used instead of methylene blue. Extraction of such an ion-pair complex into benzene has been reported (Hach, 1989). Detection Limit = 10 pg/L. 

A redder and brighter shade is obtained with isoviolanthrone. Its halogenation products are marketed as brilliant violet dyes. Related to violanthrone is the alkaline ring-closure product of 3-pyrazolanthronylbenzanthrone, which is used as a navy blue vat dye. 

Other Acid Anthraquinone Dyes. In addition to the dyes in the preceding classes, a whole series of specially developed products is available. For instance, derivatives of the anthrimide or carbazole series are known to be very light-fast gray and brown wool dyes. The post-sulfonation products of 1,5- and 1,8-diarylami-noanthraquinones are violet dyes commonly applied as mixtures. 

Orange, red, and violet dyes can be obtained by using as coupling components aminonaphtholsulfonic acids that are connected via the N atom to a 1,3,5-triazine with different aminoalkylamino, trialkylammonium alkylamino, or cyclic ammonium substituents in the 4- and 6-positions [79], e.g., 27. Dye 28 dyes paper in a scarlet shade [80],... 

Amino acids react with ninhydrin to give a violet dye. This reaction is useful for detection and quantitative analysis of amino acids. 

Besides indigo and Phoenician or Tyrian purple, the red madder and insect dyes were of particular importance for the dyeing of textile materials in earlier centuries. These dyes were used to produce the highly prized red and violet dyeings with outstanding fastness to light and... 

Thoroughly dissolve the dye in hot water, filter, add the acid, and dilute to 1.0 liter. For methyl violet dye, use 0.05 grams. 

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