Malonic acid 570542 220518783 2008-06-20T07:01:42Z Puppy8800 5404759 iw {{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]]