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gallic acid
gallic acid or 3,4,5-trihydroxybenzoic acid , C 6 H 2 (OH) 3 CO 2 H, colorless crystalline organic acid found in gallnuts, sumach, tea leaves, oak bark, and many other plants, both in its free state and as part of the tannin molecule (see tannin ). Since gallic acid has hydroxyl groups and a carboxylic acid group in the same molecule, two molecules of it can react with one another to form an ester, digallic acid. Gallic acid is obtained by the hydrolysis of tannic acid with sulfuric acid. When heated above 220°C, gallic acid loses carbon dioxide to form pyrogallol, or 1,2,3-trihydroxybenzene, C 6 H 3 (OH) 3 , which is used in the production of azo dyes and photographic developers and in laboratories for absorbing oxygen. |
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"gallic acid." The Columbia Encyclopedia, 6th ed.. 2011. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. "gallic acid." The Columbia Encyclopedia, 6th ed.. 2011. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1E1-gallicac.html "gallic acid." The Columbia Encyclopedia, 6th ed.. 2011. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1E1-gallicac.html |
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gallic acid
gal·lic ac·id / ˈgalik; ˈgôlik/ • n. Chem. an acid, C6H2(OH)3COOH, extracted from oak galls and other vegetable products, formerly used in making ink. |
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Cite this article
"gallic acid." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. "gallic acid." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1O999-gallicacid.html "gallic acid." The Oxford Pocket Dictionary of Current English. 2009. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O999-gallicacid.html |
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3,4,5-trihydroxy- benzoic acid
3,4,5-trihydroxy- benzoic acid IUPAC name for gallic acid . |
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Cite this article
"3,4,5-trihydroxy- benzoic acid." The Columbia Encyclopedia, 6th ed.. 2011. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. "3,4,5-trihydroxy- benzoic acid." The Columbia Encyclopedia, 6th ed.. 2011. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1E1-X-benzoic345.html "3,4,5-trihydroxy- benzoic acid." The Columbia Encyclopedia, 6th ed.. 2011. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1E1-X-benzoic345.html |
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