Malonic acid

Malonic acid

Names
Preferred IUPAC name Propanedioic acid
Other names Malonic acid Methanedicarboxylic acid
Identifiers
CAS Number	141-82-2 Y
3D model (Jmol)	Interactive image Interactive image
ChEBI	CHEBI:30794 Y
ChemSpider	844 Y
DrugBank	DB02175 Y
ECHA InfoCard	100.005.003
PubChem CID	867
InChI InChI=1S/C3H4O4/c4-2(5)1-3(6)7/h1H2,(H,4,5)(H,6,7) Y Key: OFOBLEOULBTSOW-UHFFFAOYSA-N Y InChI=1/C3H4O4/c4-2(5)1-3(6)7/h1H2,(H,4,5)(H,6,7) Key: OFOBLEOULBTSOW-UHFFFAOYAJ
SMILES O=C(O)CC(O)=O C(C(=O)O)C(=O)O
Properties
Chemical formula	C3H4O4
Molar mass	104.06 g·mol−1
Density	1.619 g/cm3
Melting point	135 to 137 °C (275 to 279 °F; 408 to 410 K) (decomposes)
Boiling point	decomposes
Solubility in water	Miscible
Acidity (pKa)	pKa1 = 2.83 pKa2 = 5.69
Magnetic susceptibility (χ)	-46.3·10−6 cm3/mol
Related compounds
Other anions	malonate
Related carboxylic acids	acetic acid oxalic acid propionic acid tartronic acid acrylic acid butyric acid succinic acid fumaric acid
Related compounds	propanone propionaldehyde propanedial dimethyl malonate
Hazards
Safety data sheet	External MSDS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y  (what is YN ?)
Infobox references

Malonic acid (IUPAC systematic name: propanedioic acid) is a dicarboxylic acid with structure CH₂(COOH)₂. The ionized form of malonic acid, as well as its esters and salts, are known as malonates. For example, diethyl malonate is malonic acid's diethyl ester. The name originates from the Greek word μᾶλον (malon) meaning 'apple'.

Malonic acid is often mistakenly believed to occur in beetroot at high concentration, and a study on the composition of sugar beet liquors revealed no malonic acid. It exists in its normal state as white crystals. Malonic acid is the classic example of a competitive inhibitor: It acts against succinate dehydrogenase (complex II) in the respiratory electron transport chain.

A classical preparation of malonic acid starts from chloroacetic acid:

Sodium carbonate generates the sodium salt, which is then reacted with sodium cyanide to provide the cyano acetic acid salt via a nucleophilic substitution. The nitrile group can be hydrolyzed with sodium hydroxide to sodium malonate, and acidification affords malonic acid. Industrially, however, malonic acid is produced by hydrolysis of dimethyl malonate or diethyl malonate.