Malonic acid
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220518783
2008-06-20T07:01:42Z
Puppy8800
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{{Chembox new
| Name = '''Malonic acid'''
| ImageFile = Malonic_acid structure.png
| ImageSize = 180px
| ImageName = Malonic acid
| IUPACName = propanedioic acid
| OtherNames = methanedicarboxylic acid
| Section1 = {{Chembox Identifiers
| CASNo = 141-82-2
| SMILES = O=C(O)CC(O)=O
}}
| Section2 = {{Chembox Properties
| Formula = C<sub>3</sub>H<sub>4</sub>O<sub>4</sub>
| MolarMass = 104.03 g/mol
| MeltingPt = 135 - 137 °C ''decomp.''
| Density = 1,619 g/cm<sup>3</sup>, Solid
| Solubility = Completely Soluble
| MeltingPt = 135-136°C (408-409 K)
| BoilingPt = Decomposes}}
| Section7 = {{Chembox Hazards
| ExternalMSDS = [http://physchem.ox.ac.uk/MSDS/MA/malonic_acid.html External MSDS]
}}
}}
'''Malonic acid''' ([[IUPAC]] [[systematic name]]: '''propanedioic acid''') is a [[dicarboxylic acid]] with structure [[carbon|C]][[hydrogen|H]]<sub>2</sub>([[carboxyl group|COOH]])<sub>2</sub>. The [[ion]]ised form of malonic acid, as well as its [[ester]]s and [[salt]]s, are known as '''malonates'''. For example, [[diethyl malonate]] is malonic acid's [[ethyl]] [[ester]]. The name originates from [[Latin]] ''malum'', meaning ''apple''.
==Biochemistry==
The [[calcium]] salt of malonic acid occurs in high concentrations in [[beetroot]]. It exists in its normal state as white crystals. Malonic acid is the archetypal example of a [[competitive inhibitor]]: it acts against [[succinate dehydrogenase]] (complex II) in the [[oxidative phosphorylation|respiratory electron transport chain]].
==Organic synthesis==
A classical preparation of malonic acid starts from [[acetic acid]]<ref>{{OrgSynth | title = Malonic acid | author = Nathan Weiner | collvol = 2 | collvolpages = 376 | prep = cv2p0376}}</ref>. This acid is chlorinated to chloroacetic acid. [[Sodium carbonate]] generates the sodium [[salt]] which is then reacted with [[sodium cyanide]] to the cyano acetic acid salt in a [[nucleophilic substitution]]. The [[nitrile]] group can be [[hydrolysis|hydrolysed]] with [[sodium hydroxide]] to sodium malonate and acidification affords malonic acid.
==Organic reactions==
In a well known reaction malonic acid [[condensation reaction|condenses]] with [[urea]] to [[barbituric acid]]. Malonic acid is frequently used as an [[enolate]] in [[Knoevenagel condensation]]s or condensed with [[acetone]] to form [[Meldrum's acid]]. Its esters are also used for the <sup>-</sup>CH<sub>2</sub>COOH synthon in the [[malonic ester synthesis]].
==External links==
{{commons|Malonic acid|Malonic acid}}
* pH spectrum http://www.Theoprax-Research.com [http://www.Theoprax-Research.com/fmalonS.html Disodium Malonate]
* pH spectrum http://www.Theoprax-Research.com [http://www.Theoprax-Research.com/MalonCu.html Malonic acid copper complex]
==References==
<references />
[[Category:Malonates]]
[[Category:Dicarboxylic acids]]
[[cs:Kyselina malonová]]
[[de:Malonsäure]]
[[es:Ácido malónico]]
[[fr:Acide malonique]]
[[it:Acido malonico]]
[[lv:Malonskābe]]
[[nl:Malonzuur]]
[[ja:マロン酸]]
[[no:Malonsyre]]
[[pl:Kwas malonowy]]
[[pt:Ácido malônico]]
[[ru:Малоновая кислота]]
[[fi:Malonihappo]]
[[zh:丙二酸]]