Phenol dyes

Aurin—CisH Os and Rosolicacid—CioHigOs—are substances existing in the dye obtained by the action of oxalic acid upon phenol in presence of HjSOi, known asoorallin or pceouin, which communicates to silk or wool a fine yellow-red color. 

Aurin crystallizes in fine, red needles from its solution in HCl. It is insoluble in HjO, but soluble in HCl, alcohol, and glacial acetic acid. It forms a colorless compound with potassium bisulfite. 

Phthaleins.—These substances are produced by heating the phenols with phthalic anhydrid, CsHgOs, water being at the same time eliminated. 

Their constitution is that of a benzene nucleus, two of whose H atoms have been replaced by two acetone groups (CO), whose remaining valences attach them to two phenol groups by exchange with an atom of hydrogen. 

Sesorcin-phthalein—Fluorescein—CaoHuOa—bears the same relation to resorcin that phenol-phthalein does to phenol, and is-obtained from resorcin by a corresponding method. It is a dark brown crystalline powder, which dissolves in ammonia to form a red solution, exhibiting a most brilliant green fluorescence. A tetrabromo-derivative of fluorescein is used as a dye under the name eosin. 

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Benzene (and alkylbenzene) sulphonic acids QH5SO3H Detergents, phenols, dyes... 

The reaction of 2,4,6-trihalophenols with tropylium perchlorates in the presence of triethylamine gives phenolate dye (Scheme 10) followed by acetylation to give dye 76 from which the leuco compounds 77 can be prepared103 by catalytic reduction using Pd-C/H2. 

Figure 7 shows phenol, dye, oxygen and suspended biomass concentrations and biofilm thickness as a function of time. 

Selectivity of Mg2+ against Ca2+ is achieved by using RO ligands such as phenoles, enolates, or hydroxide, and using nitrogen donors (e.g., 8-hydroxy-quinolinate or diazo-phenol dyes). In biology this may not be necessary as biology can control Ca2+ concentration very well. 

Hydroxyazo dyes vary in the proportion of tautomers present, from pure azo tautomer to mixtures of azo and hydrazone tautomers, to pure hydrazone tautomer. Almost all azo phenol dyes (64) exist totally in the azo form, except for a few special cases [4],... 

Jung et al. [58] obtained permethylated a-CD bridged with (nitrophenylazo)-phenol dye (Figure 21). This compound exhibits time-dependend UV-Vis and NMR spectra in aqueous solutions at room temperature in the dark. This phenomenon was interpreted in terms of self-aggregation involving intermolecular inclusion of the p-nitrophenylazophenol group with one of the two permethylated cyclodextrin residues of the original compound. 

Jung, J.H., Takehisa, C., Sakata, Y., and Kaneda, T. (1996) p-(4-Nitrophenylazo)phenol Dye-bridged Permethylated a-Cyclodextrin Dimer Synthesis and Self-aggregation in Dilute Aqueous Solution, Chem. Lett. 147-148. 

In general, the sulfonic acids are water soluble and are strong acids because of virtually complete loss of ionizable H+ in aqueous solution. They have some important commercial applications, such as in the hydrolysis of fats and oils (see Section 3.5) to fatty acids and glycerol. Benzenesulfonic acid is fused with NaOH in the preparation of phenol. Dyes and some pharmaceutical compounds are manufactured from p-toluenesulfonic acid. Methanesulfonic acid has been developed as an esterification catalyst in place of sulfuric acid for the synthesis of resins in paints and coatings. 

Oxidation of phenols, dyes, and polycyclic aromatic hydrocarbons [48,49], decolorization of Kraft bleaching effluents, binding of phenols and aromatic amines with humus [47] Transformation of phenols, aromatic amines, polyaromatic hydrocarbons, and other aromatic compounds, decolorization of Kraft bleaching effluents, treatment of dioxins, pyrene [86-89,114] Improved sludge dewatering [59]... 

To gain a better understanding of the effect of protein fiber type, dye, and mordant on sunlight and burial weathering processes, we dyed wool and silk with three phenolic dyes (found as major components in natural dye mixtures extracted from various plant sources) and post-mordanted samples of the dyed fabrics with five representative metal salts. We then exposed the unmordanted and the dyed-mordanted samples to simulated sunlight or soil burial and measured the differences in the color and tensile properties that resulted from these treatments. 

Just as collagen fibers may suffer changes in staining properties so may elastin if it is damaged by the action of enzymes or by too severe isolation procedures. Rupture of a peptide bond results in the appearance of a new a-amino and a new a-carboxyl group and these added to the very few acidic and basic groups in elastin result in a much increased affinity for acidic and basic dyes. Concurrently the affinity for phenolic dyes may be reduced, particularly in acid or alkaline solutions, due to the repulsive forces set up by the increased charge. 

TABLE 2. Commercially available phenolic dyes listed in the Color Index (Cl)... 

This reaction is also applicable to 1,8-diamino-4-naphthalenesulfonic acid, t,8-diamino-3,6-naphthalenedisulfonic acid (24) and to the indo-phenol dyes of 1,8-naphthalenediamine with p-aminophenol and 4-amino-2,6-dichlorophenol. Owing to the liberation of hydrogen sulfide during the cyclization, the leuco-indophenol dyes of 2,3-dihydro-fH-periniidine-2-thione are obtained (25). 

The catalysts used depend upon the compound that has to be removed (Table 6.6). Some catalysts used for the removal of different compoimds such as phenol, dye solutions. Some of zeolite synthesised methods are shown in Table 6.7. 

The major application of electrochemical ozone cells is in the oxidation of water-based species (in order to provide sterilization) and the oxidation of industrial process liquors containing cyanides or organicSte.g. phenols, dyes and pesticides, In such applications it is environmentally more desirable than CI2 or OCl" treatment (Chapter 7) as the latter chemicals may leave a range of undesirable species. Ozone treatments may be advantageously coupled with ultraviolet treatments in order to remove certain persistent chemicals (such as certain pesticides or polychlorinated biphenyls). In the case of sterilization of potable water the cells are likely to remain small modular designs (Fig. 5,15(b)). While the O3 required is very dependent on inlet-water quality, a cell of 100 cm anode area may service up to KKK) m day of water at the 1 mg dm O3 dose level... 

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