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Phthaleins
Phthalein dyes are a class of dyes mainly used as pH indicators, due to their ability to change colors depending on pH. They are formed by the reaction of phthalic anhydride with various phenols. They are a subclass of triarylmethane dyes. Common phthalein dyes include: *Bromothymol blue *Bromocresol green *Bromocresol purple *Cresol Red * ''o''-Cresolphthalein * Chlorophenol red * Dixylenolphthalein * Guaiacolphthalein * α-Naphtholphthalein * Phenolphthalein * Phenolsulfonphthalein * Tetrabromophenolphthalein * Thymol blue * Thymolphthalein * Xylenolphthalein See also *Triarylmethane dye Triarylmethane dyes are synthetic organic compounds containing triphenylmethane backbones. As dyes, these compounds are intensely colored. They are produced industrially as dyes. Families Triarylmethane dyes can be grouped into families accordin ... References Triarylmethane dyes Phthalides {{organic-compound-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenol Red
Phenol red (also known as phenolsulfonphthalein or PSP) is a pH indicator frequently used in cell biology laboratories. Chemical structure and properties Phenol red exists as a red crystal that is stable in air. Its solubility is 0.77 grams per liter (g/L) in water and 2.9 g/L in ethanol.''Merck Index'', 11th ed., 7213 Phenolsulfonphtalein It is a weak acid with p''K''a = 8.00 at . A solution of phenol red is used as a pH indicator, often in cell culture. Its color exhibits a gradual transition from yellow ( λmax = 443 nm) to red (λmax = 570 nm) over the pH range 6.8 to 8.2. Above pH 8.2, phenol red turns a bright pink (fuchsia) color.''Merck Index'', 13th ed., 7329 PhenolsulfonphthaleinBeilstein 5-19-03-00457 In crystalline form, and in solution under very acidic conditions (low pH), the compound exists as a zwitterion as in the structure shown above, with the sulfate group negatively charged, and the ketone group carrying an additional proton. This form is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bromocresol Green
Bromocresol green (BCG) is a dye of the triphenylmethane family (triarylmethane dyes). It belongs to a class of dyes called sulfonephthaleins. It is used as a pH indicator in applications such as growth mediums for microorganisms and titrations. In clinical practise, it is commonly used as a diagnostic technique. The most common use of bromocresol green is to measure serum albumin concentration within mammalian blood samples in possible cases of kidney failure and liver disease. Properties In aqueous solution, bromocresol green will ionize to give the monoanionic form (yellow), that further deprotonates at higher pH to give the dianionic form (blue), which is stabilized by resonance: : The acid dissociation constant (p''K''a) of this reaction is 4.8. Tap water is sufficiently basic to give a solution of bromocresol green its characteristic blue-green color. The acid and basic forms of this dye have an isosbestic point in their UV-Visible spectrum, around 515 nm, ind ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thymolphthalein
Thymolphthalein is a phthalein dye used as an acid– base ( pH) indicator. Its transition range is around pH 9.3–10.5. Below this pH, it is colorless; above, it is blue. The molar extinction coefficient for the blue thymolphthalein dianion is 38,000 M−1 cm−1 at 595 nm. Thymolphthalein is also known to have use as a laxative and for disappearing ink. Preparation Thymolphthalein can be synthesized from thymol and phthalic anhydride Phthalic anhydride is the organic compound with the formula C6H4(CO)2O. It is the anhydride of phthalic acid. Phthalic anhydride is a principal commercial form of phthalic acid. It was the first anhydride of a dicarboxylic acid to be used commer .... : References {{reflist PH indicators Triarylmethane dyes Phthalides Phenols Isopropyl compounds ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenolphthalein
Phenolphthalein ( ) is a chemical compound with the chemical formula, formula carbon, C20hydrogen, H14oxygen, O4 and is often written as "HIn", "HPh", "phph" or simply "Ph" in shorthand notation. Phenolphthalein is often used as an indicator in acid–base titrations. For this application, it turns colorless in acidic solutions and pink in base (chemistry), basic solutions. It belongs to the class of dyes known as phthalein dyes. Phenolphthalein is slightly soluble in water and usually is dissolved in Alcohol (chemistry), alcohols for use in experiments. It is a weak acid, which can lose H+ ions in solution. The nonionized phenolphthalein molecule is colorless and the double deprotonated phenolphthalein ion is Fuchsia (color), fuchsia. Further loss of proton in higher pH occurs slowly and leads to a colorless form. Phenolphthalein ion in concentrated sulfuric acid is orange red due to sulfonation. Uses pH indicator Phenolphthalein's common use is as an indicator in acid-base t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triarylmethane Dye
Triarylmethane dyes are synthetic organic compounds containing triphenylmethane backbones. As dyes, these compounds are intensely colored. They are produced industrially as dyes. Families Triarylmethane dyes can be grouped into families according to the nature of the substituents on the aryl groups. In some cases, the anions associated with the cationic dyes (say crystal violet) vary even though the name of the dye does not. Often it is shown as chloride. Methyl violet dyes Methyl violet dyes have dimethylamino groups at the ''p''-positions of two aryl groups. Image:Methyl Violet 2B.png, Methyl violet 2B Image:Methyl Violet 6B.png, Methyl violet 6B Image:Methyl Violet 10B.png, Methyl violet 10B Fuchsine dyes Fuchsine dyes have primary or secondary amines (NH2 or NHMe) functional groups at the ''p''-positions of each aryl group. File:Pararosaniline.png, Pararosaniline File:Rosaniline hydrochloride.svg, Fuchsine (hydrochloride salt) Neofuchsin.svg, New fuchsine (As chlorid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thymol Blue
Thymol blue (thymolsulfonephthalein) is a brownish-green or reddish-brown crystalline powder that is used as a pH indicator. It is insoluble in water but soluble in alcohol and dilute alkali solutions. It transitions from red to yellow at pH 1.2–2.8 and from yellow to blue at pH 8.0–9.6. It is usually a component of Universal indicator __FORCETOC__ A universal indicator is a pH indicator made of a solution of several compounds that exhibits several smooth colour changes over a wide range pH values to indicate the acidity or alkalinity of solutions. Although there are several .... At wavelength (378 - 382) nm, extinction coefficient > 8000 and at wavelength (298 - 302) nm , the extinction coefficient > 12000. Structures Thymol blue has different structures at different pH. :thymol blue. Safety It may cause irritation. Its toxicological properties have not been fully investigated. Harmful if swallowed, Acute Toxicity. Only Hazardous when percent values are above 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
α-Naphtholphthalein
α-Naphtholphthalein (C28H18O4) is a phthalein dye used as a pH indicator A pH indicator is a halochromic chemical compound added in small amounts to a solution so the pH (acidity or basicity) of the solution can be determined visually or spectroscopically by changes in absorption and/or emission properties. Hence, ... with a visual transition from colorless/reddish to greenish blue at pH 7.3–8.7. References PH indicators 1-Naphthols Phthalides Triarylmethane dyes {{organic-compound-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorophenol Red
Chlorophenol red is an indicator dye that changes color from yellow to violet in the pH range 4.8 to 6.7. The pH of a substance is determined by taking the negative logarithm of the Hydronium ion concentration and the indictor changes color due to the dissociation of H+ ions. The lambda max is at 572 nm. Properties and Uses of Chlorophenol Red The dissociation mechanism of Chlorophenol Red is similar to that of phenolphthalein meaning it can be used as a color indicator. The dissociation of hydroxyl In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydro ... and hydrogen atoms creates the dissociate scheme of chlorophenol red to change color from yellow to red. The pH properties of chlorophenol red are used to selectively determine the amount of chlorine dioxide in drinking water. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
