5707. Malic Acid

Nomenclature

CAS number: 6915-15-7
Hydroxybutanedioic acid; hydroxysuccinic acid.
C4H6O5; mol wt 134.09.
C 35.83%, H 4.51%, O 59.66%.

Description and references

The naturally occurring isomer is the l-form which has been found in apples and many other fruits and plants. Prepn of d- and dl-forms, and resolution of racemic mixture: McKenzie et al., J. Chem. Soc. 123, 2875 (1923). Solubilities: Descamps, Bull. Soc. Chim. Belg. 49, 91 (1940). Microbial production of l-form: Kitahara; Abe et al., US 2972566; US 3063910 (1961, 1962, both to Kyowa). Configuration: J. A. Mills, W. Klyne in Progress in Stereochemistry vol. 1, W. Klyne, Ed. (Academic Press, New York, 1954) pp 182-183; E. L. Eliel, Stereochemistry of Carbon Compounds (McGraw-Hill, New York, 1962) pp 97-98; Cymerman-Craig, Roy, Tetrahedron 21, 1847 (1965). Review of uses: Manuf. Chem. Aerosol News 35, 56 (December, 1964). Review: S. E. Berger, “Hydroxy Dicarboxylic Acids” in Kirk-Othmer Encyclopedia of Chemical Technology vol 13 (Wiley-Interscience, New York, 3rd ed., 1981) pp 103-110.

Chemical structure

Derivative

dl-Form.

Nomenclature

CAS number: 617-48-1

Properties

Crystals, mp 131-132°. Soly in g/100 g solvent at 20°: methanol 82.70, diethyl ether 0.84, ethanol 45.53, acetone 17.75, dioxane 22.70, water 55.8. Practically insol in benzene.

Derivative

d-(+)-Form.

Nomenclature

CAS number: 636-61-3

Properties

Crystals, mp 101°.

Derivative

l-(-)-Form.

Nomenclature

CAS number: 97-67-6
Apple acid.

Properties

Crystals from acetone, or acetone + CHCl3, mp 100°. Dec ≈140°. [α]D -2.3° (c = 8.5). Soly in g/100 g solvent at 20°: methanol 197.22, diethyl ether 2.70, ethanol 86.60, acetone 60.66, dioxane 74.35, water 36.35. Practically insol in benzene.

Use

Intermediate in chemical synthesis. Chelating and buffering agent. Flavoring agent, flavor enhancer and acidulant in foods.