Malic acid

Malic acid
Skeletal structure
Ball-and-stick model

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 Edit this at Wikidata
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) checkY
    Key: BJEPYKJPYRNKOW-UHFFFAOYSA-N checkY
  • 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)[1]
Acidity (pKa) pKa1 = 3.40
pKa2 = 5.20[2]
pKa3 = 14.5[3]
Hazards
GHS labelling:
GHS07: Exclamation mark
Flash point 203 °C[4]
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 checkY☒N ?)

Malic acid is an organic compound with the molecular formula HO2CCH(OH)CH2CO2H. 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.

  1. ^ "chemBlink Database of Chemicals from Around the World". chemblink.com. Archived from the original on 2009-01-22.
  2. ^ Data for biochemical research (3rd ed.). Oxford: Clarendon Press. 1986. ISBN 0-19-855358-7. OCLC 11865673.
  3. ^ Silva, Andre M. N.; Kong, Xiaole; Hider, Robert C. (2009). "Determination of the pKa value of the hydroxyl group in the α-hydroxycarboxylates citrate, malate and lactate by 13C NMR: implications for metal coordination in biological systems". BioMetals. 22 (5): 771–778. doi:10.1007/s10534-009-9224-5. ISSN 0966-0844. PMID 19288211.
  4. ^ "DL-Malic acid - (DL-Malic acid) SDS". Merck Millipore.