Malic acid

Malic acid is an organic compound with the molecular formula C4H6O5. It is a dicarboxylic acid that is made by all living organisms, contributes to the sour taste of fruits, and is used as a food additive. Malic acid has two stereoisomeric forms (L- and D-enantiomers), though only the L-isomer exists naturally. The salts and esters of malic acid are known as malates. The malate anion is a metabolic intermediate in the citric acid cycle.

Malic acid

DL-Malic acid
Names
Preferred IUPAC name
2-Hydroxybutanedioic acid
Other names
  • Hydroxybutanedioic acid
  • 2-Hydroxysuccinic acid
  • (L/D)-Malic acid
  • (±)-Malic acid
  • (S/R)-Hydroxybutanedioic acid
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.027.293
EC Number
  • 230-022-8
E number E296 (preservatives)
KEGG
UNII
  • InChI=1S/C4H6O5/c5-2(4(8)9)1-3(6)7/h2,5H,1H2,(H,6,7)(H,8,9) Y
    Key: BJEPYKJPYRNKOW-UHFFFAOYSA-N Y
  • InChI=1/C4H6O5/c5-2(4(8)9)1-3(6)7/h2,5H,1H2,(H,6,7)(H,8,9)
    Key: BJEPYKJPYRNKOW-UHFFFAOYAM
  • O=C(O)CC(O)C(=O)O
Properties
C4H6O5
Molar mass 134.09 g/mol
Appearance Colorless
Density 1.609 g⋅cm−3
Melting point 130 °C (266 °F; 403 K)
558 g/L (at 20 °C)
Acidity (pKa) pKa1 = 3.40
pKa2 = 5.20
Hazards
GHS labelling:
Flash point 203 °C
Related compounds
Other anions
Malate
Succinic acid
Tartaric acid
Fumaric acid
Related compounds
Butanol
Butyraldehyde
Crotonaldehyde
Sodium malate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references
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