View source for Tartaric acid

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{| align="right" border="1" cellspacing="0" cellpadding="3" style="margin: 0 0 0 0.5em; background: #FFFFFF; border-collapse: collapse; border-color: #C0C090;"
! {{chembox header}}| '''Tartaric acid'''
|-
{{Chembox/Image|Tartaric acid.png|Tartaric acid}}
|-
| [[IUPAC nomenclature|Systematic name]]
| 2,3-dihydroxybutanedioic acid
|-
| Other names
| 2,3-dihydroxysuccinic acid<br>threaric acid<br>racemic acid<br>uvic acid<br>paratartaric acid
|-
{{Chembox/Formula|C<sub>4</sub>H<sub>6</sub>O<sub>6</sub>}}
{{Chembox/SMILES|<nowiki>C(C(C(=O)O)O)(C(=O)O)O</nowiki>}}
{{Chembox/MolarMass|150.087}}
{{Chembox/Appearance|white powder}}
{{Chembox/CASNo|526-83-0}}
{{Chembox/SectProperties}}
{{Chembox/SolubilityWater|133|20}}
{{Chembox/MeltingPt|168-170°C}}
{{Chembox/Bottom}}


{{CMG}}



==Overview==
'''Tartaric acid''' is a white crystalline [[organic acid]]. It occurs naturally in many plants, particularly [[grape]]s, [[banana]]s, and [[tamarind]]s, and is one of the main acids found in [[wine]]. It is added to other foods to give a sour taste, and is used as an [[antioxidant]]. Salts of tartaric acid are known as [[tartrate]]s. It is a di[[hydroxyl|hydroxy]] derivative of di[[carboxylic acid]].

Tartaric acid was first isolated from [[potassium tartrate]], known to the ancients as [[cream of tartar|tartar]], c. [[800]] by the [[Persian people|Persian]] [[alchemy|alchemist]] [[Jabir ibn Hayyan]], who was also responsible for numerous other basic chemical processes still in use today. The modern process was developed in [[1769]] by the [[Sweden|Swedish]] chemist [[Carl Wilhelm Scheele]].  The [[chirality (chemistry)|chirality]] of tartaric acid was discovered in 1832 by [[Jean Baptiste Biot]], who observed its ability to rotate polarized light.  [[Louis Pasteur]] continued this research in [[1847]] by investigating the shapes of tartaric acid crystals, which he found to be asymmetric.  Pasteur was the first to produce a pure sample of levotartaric acid.

==Stereochemistry==

Naturally-occurring tartaric acid is [[chirality (chemistry)|chiral]], meaning that it has molecules that are non-superimposable on their mirror-images. It is a useful raw material in organic chemistry for the synthesis of other chiral molecules. The naturally occurring form of the acid is '''<small>L</small>-(+)-tartaric&nbsp;acid''' or '''dextrotartaric&nbsp;acid'''.
The mirror-image (enantiomeric) form, '''levotartaric&nbsp;acid ''' or '''<small>D</small>-(−)-tartaric&nbsp;acid''', and the achiral form, '''mesotartaric&nbsp;acid''', can be made artificially. Note, that the ''dextro'' and ''levo'' prefixes are not related to the D/L configuration (which is derived from the reference <small>D</small>- or <small>L</small>-[[glyceraldehyde]]), but to the orientation of the [[optical rotation]], (+) = dextrorotatory, (−) = levorotatory. Sometimes, instead of capital letters, small italic ''d'', ''l'' are used. They are abbreviations of ''dextro''- and ''levo''-, and nowadays should not be used. Levotartaric and dextrotartaric acid are [[enantiomer]]s, mesotartaric acid is a [[diastereomer]] of both of them. 

A rarely occurring optically inactive form of tartaric acid, '''<small>DL</small>-tartaric acid''' is a 
1:1 mixture of the ''levo'' and ''dextro'' forms. It is distinct from mesotartaric acid and was called
'''racemic&nbsp;acid''' (from [[Latin]] ''racemus'' - "a bunch of grapes"). The word ''racemic'' later changed its meaning, becoming a general term for 1:1 enantiomeric mixtures - [[racemate]]s.

{| align="center" cellpadding="5" cellspacing="0"
! levotartaric acid<br><small>(<small>D</small>-(−)-tartaric acid)</small> !! dextrotartaric acid<br><small>(<small>L</small>-(+)-tartaric acid)</small> !! mesotartaric acid
|-
| align="center" width="150" style="border-right:1px dashed black;" |
[[Image:D-tartaric acid.png]]
| align="center" width="150" style="border-right:1px solid black;" | [[Image:L-tartaric acid.png]]
| align="center" width="270" | [[Image:DL-tartaric acid.png]]
|-
| align="center" colspan="2"  valign="bottom" style="border-right:1px solid black;border-top:1px dashed black;" |
'''<small>DL</small>-tartaric acid (racemic acid)'''<br><small>(when in 1:1 ratio)</small>
|
|}

{| align="center" border="1" cellspacing="0" cellpadding="5px" background: #FFFFFF; border-collapse:collapse; border-color: #C0C090;"
! {{chembox header}} colspan=7| '''Forms of Tartaric Acid'''
|- align="center" style="background:#DADADA;"
| [[Common name]]
| tartaric acid
| levotartaric acid
| dextrotartaric acid
| mesotartaric acid
| racemic acid
|-align="center"
| Synonyms
| 
| <small>D</small>-(''S'',''S'')-(−)-tartaric acid <br> unnatural isomer
| <small>L</small>-(''R'',''R'')-(+)-tartaric acid <br> natural isomer
|(2''R'',3''S'')-tartaric acid
| <small>DL</small>-(''S'',''S''/''R'',''R'')-(±)-tartaric acid
|-align="center"
| [[PubChem]]
| {{PubChemCID|875}}
| {{PubChemCID|439655}}
| {{PubChemCID|444305}}
| {{PubChemCID|78956}}
| {{PubChemCID|5851}}
|-align="center"
| [[EINECS number]]
| 
| {{EINECS|205-695-6}}
| {{EINECS|201-766-0}}
| {{EINECS|205-696-1}}
| {{EINECS|205-105-7}}
|-align="center"
| [[CAS number]]
| 526-83-0
| 147-71-7
| 87-69-4
| 147-73-9
| 133-37-9
|}

==Derivatives==<!-- This section is linked from [[Napoleon I of France]] -->
[[Image:CommercialTartaric.jpg|thumb|225px|Commercially produced tartaric acid.]]
Important derivatives of tartaric acid include its salts, [[Potassium bitartrate|Cream of tartar]] (potassium bitartrate), [[Rochelle salt]] (potassium sodium tartrate, a mild [[laxative]]) and tartar emetic (antimony potassium tartrate).

Tartaric acid is a [[muscle]] [[toxin]], which works by inhibiting the production of [[malic acid]], and in high doses causes paralysis and death.  The minimum recorded fatal dose for a human is about 7,5 grams/kg.
In spite of that, it is included in many foods, especially sour-tasting [[sweet]]s. As a [[food additive]], tartaric acid is used as an [[antioxidant]] with [[E number]] '''E334''', [[tartrate]]s are other additives serving as antioxidants or [[emulsifier]]s.

When cream of tartar is added to [[water]], a suspension results which serves to clean [[copper]] [[coin]]s very well.  This is due to the fact that the tartrate solution can dissolve the layer of copper(II) oxide present on the surface of the coin. The resulting Copper(II)-tartrate complex that results is easily soluble in water.

==Tartaric acid in wine==
[[Image:HomemadeTartaric.jpg|thumb|225px|Unpurified tartaric acid, separated from grape juice, can take on the color of the latter.]]
Tartaric acid may be most immediately recognizable to wine drinkers as the source of "wine diamonds," the small [[potassium bitartrate]] crystals that sometimes form spontaneously on the [[cork (material)|cork]]. These "tartrates" are harmless, despite sometimes being mistaken for broken glass, and are prevented in many wines through [[cold stabilization]]. The tartrates that remain on the inside of [[aging barrel]]s were at one time a major industrial source of potassium bitartrate.

However, tartaric acid plays an important role chemically, lowering the pH of fermenting "must" to a level where many undesirable spoilage bacteria cannot live, and acting as a preservative after [[fermentation (food)|fermentation]]. In the mouth, tartaric acid provides some of the tartness that is currently out of fashion in the wine world, although [[citric acid|citric]] and [[malic acid]]s also play a role. The modern practice of extended hang time, where grapes are allowed to sit on the vine nearly until they become [[raisin]]s, can dramatically reduce the taste of tartaric acid in a wine, leaving it smoother but also potentially less compatible with food.

== External links ==
*[http://www.linanwindow.com/tartaric/history.htm "History of Tartaric Acid" from Linan Euro-China Co., Ltd.]


{{commons|Tartaric acid}}

[[Category:Hydroxy acids]]
[[Category:Dicarboxylic acids]]
[[Category:Food antioxidants]]
[[Category:Food acidity regulators]]
[[Category:Oenology]]

[[bg:Винена киселина]]
[[ca:Àcid tàrtric]]
[[cs:Kyselina vinná]]
[[de:Weinsäure]]
[[el:Τρυγικό οξύ]]
[[es:Ácido tartárico]]
[[eo:Tartrata acido]]
[[fr:Acide tartrique]]
[[he:חומצה טרטרית]]
[[it:Acido tartarico]]
[[hu:Borkősav]]
[[nl:Wijnsteenzuur]]
[[ja:酒石酸]]
[[lv:Vīnskābe]]
[[pl:Kwas winowy]]
[[pt:Ácido tartárico]]
[[ru:Винная кислота]]
[[fi:Viinihappo]]
[[sk:Kyselina vínna]]
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[[zh:酒石酸]]
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