Gallic acid 291767 200909192 2008-03-25T22:14:16Z Hellbus 290570 {{Chembox new | Name = Gallic acid | ImageFile = Gallic acid.svg <!-- | ImageSize = 150px --> | ImageName = Gallic acid | IUPACName = 3,4,5-hydroxybenzoic acid | OtherNames = Gallic acid | Section1 = {{Chembox Identifiers | SMILES = Oc1cc(cc(O)c1O)C(O)=O | CASOther = [149-91-7] (Anhydrous)<br />[5995-86-8] (Monohydrate) }} | Section2 = {{Chembox Properties | Formula = C<sub>7</sub>H<sub>6</sub>O<sub>5</sub> | MolarMass = 170.12 g/mol | Appearance = White, yellowish-white, or<br />pale fawn-colored crystals. | Density = 1.7 g/cm<sup>3</sup> (anhydrous) | Solubility = 1.1g/100ml water @ 20°C (anhydrous)<br />1.5g/100ml water @ 20°C (monohydrate) | MeltingPt = 250°C (523 K) | BoilingPt = (? K) | pKa = COOH: 4.5, OH: 10. }} | Section3 = {{Chembox Structure | CrystalStruct = | Dipole = }} | Section7 = {{Chembox Hazards | ExternalMSDS = [http://bulkpharm.mallinckrodt.com/_attachments/msds/G0806.htm External MSDS] | MainHazards = Irritant }} | Section8 = {{Chembox Related | Function = [[phenol]]s,<br />[[carboxylic acid]]s | OtherFunctn = | OtherCpds = [[Benzoic acid]], [[Phenol]] }} }} '''Gallic acid''' is an [[organic acid]], also known as 3,4,5-trihydroxy[[benzoic acid]], found in [[gallnut]]s, [[sumac]], [[witch hazel]], [[tea]] leaves, [[oak]] [[bark]], and other [[plant]]s. The chemical formula is [[carbon|C]]<sub>6</sub>[[hydrogen|H]]<sub>2</sub>([[oxygen|OH]])<sub>3</sub>COOH. Gallic acid is found both free and as part of [[tannin]]s. [[Salts]] and [[ester]]s of gallic acid are termed [[gallate]]s. Despite its name, it does not contain [[gallium]]. Gallic acid is commonly used in the pharmaceutical industry.{{Fact|date=March 2008}} It is used as a [[standard]] for determining the [[phenol]] content of various analytes by the [[Folin-Ciocalteau assay]]; results are reported in ''gallic acid equivalents''.<ref>{{cite web | author = Andrew Waterhouse | title = Folin-Ciocalteau Micro Method for Total Phenol in Wine | publisher = [[UC Davis]] | url = http://waterhouse.ucdavis.edu/phenol/folinmicro.htm}}</ref> Gallic acid can also be used to synthesize the hallucinogenic alkaloid [[mescaline]], also known as 3,4,5-trimethoxyphenethylamine.{{Fact|date=March 2008}} Gallic acid was one of the substances used by [[Angelo Mai]] among other early investigators of [[palimpsest]]s to clear the top layer of text off and reveal hidden manuscripts underneath. Mai was the first to employ it, but did so "with a heavy hand," often damaging manuscripts for future study.{{Fact|date=March 2008}} ==See also== *[[Pyrogallol]] *[[Syringol]] *[[Syringaldehyde]] ==References== {{citationstyle|date=September 2007}} *LD Reynolds and NG Wilson, “Scribes and Scholars” 3rd Ed. Oxford: 1991. pp193–4. <references/> ==External links== *[http://www.henriettesherbal.com/eclectic/kings/acidum-gall.html King's American Dispensatory (1898) entry on Gallic acid] [[Category:Benzoic acids]] [[Category:Phenols]] [[Category:Astringent flavors]] [[cs:Kyselina gallová]] [[de:Gallussäure]] [[fr:Acide gallique]] [[it:Acido gallico]] [[nl:Galluszuur]] [[ja:没食子酸]] [[pl:Kwas galusowy]] [[ru:Галловая кислота]] [[fi:Gallushappo]] [[zh:没食子酸]]