5703. Maleic Acid

Nomenclature

CAS number: 110-16-7
(Z)-Butenedioic acid; toxilic acid; cis-1,2-ethylenedicarboxylic acid.
C4H4O4; mol wt 116.07.
C 41.39%, H 3.47%, O 55.14%.

Description and references

Prepd by the catalytic oxidation of benzene over vanadium pentoxide: Bhattacharyya, Venkataraman, J. Appl. Chem. 8, 728 (1958); Saffer, Olenberg, FR 1321416 (1963 to Scientific Design), C.A. 59, 11265d (1963). Crystal structure: Shahat, Acta Crystallogr. 5, 763 (1952). Review: W. D. Robinson, R. A. Mount in Kirk-Othmer Encyclopedia of Chemical Technology vol. 14 (Wiley-Interscience, New York, 3rd ed., 1981) pp 770-793.

Chemical structure

Properties

White crystals from water, mp 138-139°; from alcohol and benzene, mp 130-131°. Faint, acidulous odor; characteristic repulsive, astringent taste. d 1.59. Is converted in part into the much higher-melting fumaric acid (mp 287°) when heated to a temp slightly above the melting point. Freely sol in water or alcohol. Sol in acetone, glacial acetic acid. Slightly sol in ether. Practically insol in benzene.

Caution

Strong irritant.

Use

Manuf artificial resins; to retard rancidity of fats and oils in 1:10,000 (these are said to keep 3 times longer than those without the acid); dyeing and finishing wool, cotton, and silk; preparing the maleate salts of antihistamines and similar drugs.