Phthalein dye

Phthaleins. Dyes of this class are usually considered to be triaryhnethane derivatives. Phenolphthalein [77-09-8] (23, R = CO) and phenol red [143-74-8] (23, R = SO2) are used extensively as indicators in colorimetric and titrimetric determinations (see Hydrogen-ION activity). These compounds are prepared by the condensation of phenol with phthaUc anhydride or i9-sulfoben2oic anhydride, respectively, in the presence of a dehydrating agent. 

In this case the sulphonic acid group is present in a sulphon-phthalein dye namely the indicator bromophenol blue. As in the previous example, the species (R3NH + )(R S03 ) can be extracted into chloroform whilst the indicator itself is not extracted, and the colour of the extract is proportional to the quantity of surfactant in the material under test. 

Phthalazinone, 19 332 o-Phthaldialdehyde-2-mercaptoethanol, chiral derivatizing reagent, 6 76t Phthalein dyes, 19 304-305 Phthalic acid, 19 332... 

Various phthalein dyes have been proposed for detection and determination of H2O2, with different operating principles, such as direct measurement of the dye and complex formation. The FOX assay is based on the oxidation of Fe(II) to Fe(III), followed by complex formation of the latter ion with Xylenol Orange (71). The concentration of the complex is measured at = 560 nm (e = 4.3 x 10 The linearity... 

Phthalein dyes, hydrogen peroxide determination, 628-9 Phthaloyl peroxide, luminol chemilumine scence, 1245 Physiological matrices... 

Phthaleins. Dyes of Uiis class are usually considered to be tnaryl-methane derivatives. Phenolphthalein and phenol red are used extensively as indicators in colorimetric and titrimetric determinations. See also Hydrogen-Ion Activity. 

In a related phthalein dye, however, this condition is fully met. The dye fluorescein is resorcinol phthalein and is made from phthalic anhydride or phthalyl chloride and resorcinol just as phenol phthalein is made from phthalic anhydride and phenol (p. 750). These relationships may be expressed as follows writing the final dye salt both as a tri-phenyl methane derivative (B) and as a pyronine (C). The reactions are exactly analogous to those given for the preparation of phenolphthalein and its dye salt (p. 750), some of the intermediate steps being omitted in the present case. 

Use Dyes (aniline dyes, phthalein dyes), alkylation and condensation catalyst, iodides, iodates, antiseptics and germicides, X-ray contrast media, food and feed additive, stabilizers, photographic film, water treatment, pharmaceuticals, medicinal soaps, unsaturation indicator. 

Fia. 1. The structure of some phthalein dyes. (A) Phenol tetrachlorophthalein (B) tetraiodophenolphthalein (C) phenol tetrabromophthalein disulfonate (BSP) (D) phenol 3,6-dibromophthalein disulfonate (E) phenol sulfonephthalein (phenol red) (F) tetraiodotetrachlorofluorescein (rose bengal). 

It should be noted that some iodinated phthalein dyes, e.g., tetraiodo-phenolphthalein and phenol tetraiodophthalein have been used in cholecystography. These compounds are very similar to BSP structurally and probably competitively inhibit uptake and excretion of the dye. 

R22. Rosenthal, 8. M., and White, E. C., Studies in hepatic function. VI. A. The pharmacological behavior of certain phthalein dyes. B. The value of selected phthalein compounds in estimation of hepatic function. J. Pharmacol. Exptl. Therap. 24, 265-288 (1924). 

OTHER COMMENTS used in the manufacture of dyes (aniline dyes, phthalein dyes), iodine compounds (iodides, iodates), antiseptics, and germicides used to reduce friction of hard surfaces, including glass and stainless steel also used as an alkylation and condensation catalyst in the preparation of aromatic amines, in sulfonations and sulfations useful as x-ray contrast media, as stabilizers, food and feed additives, and in water treatment important reagent in analytical chemistry has also been used in pharmaceuticals and medicinal soaps artificial isotopes of iodine are used in biochemical, biological, and chemical structure research. 

Industrial Products. Fischer s thesis leading to the doctorate at Strasbourg in 1874, was concerned with phthalein dyes, particularly fluorescein and ordn-phthalein. At Munich, Emil and cousin Otto Fischer investijpited rosaniline, the dye prepared by A. von Hofman in 1862 by the oxidation of aniline and toluidine. They converted one... 

As encapsulation of the guest depends on shape and size, tetrahedral lacton, which can better fit the cavity of the coordination cage, encapsulated and stabilized more than quinone. This can shift the equilibrium of two forms toward lactonization and disappearance of pink color. In this way, cavity-directed (and not pH-dependent) chromism can be obtained. Therefore, phthalein dyes remain colorless, even in a basic solution. Upon release of phthalein dyes by the addition of a competitive guest, the pink color will be recovered. The authors believed that this procedure could be used to control the responsiveness of target compounds to external stimuli without any chemical modification [46]. 

Takezawa H, et al. Cavity-directed chromism of phthalein dyes. J Am Chem Soc 2015 137 7043-6. 

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