8004. Pyromellitic Acid

Nomenclature

CAS number: 89-05-4
1,2,4,5-Benzenetetracarboxylic acid.
C10H6O8; mol wt 254.15.
C 47.26%, H 2.38%, O 50.36%.

Description and references

Prepd by heating mellitic (benzenehexacarboxylic) acid with KHSO4 and H2SO4: Silberrad, J. Chem. Soc. 89, 1795 (1906) (actually the dianhydride, mp 286°, is obtained by this method). Laboratory prepn from pine or spruce charcoal: Philippi, Thelen, Org. Synth. coll. vol. II, 551 (1943); by oxidation of benzene derivatives contg substituents in the 1,2,4,5 positions: Jacobsen, Ber. 17, 2516 (1884).

Chemical structure

Derivative

Dihydrate.

Properties

Triclinic plates from water. When anhydr, mp 276°. Distills with anhydride formation. 1.5 g (anhydr) dissolves in 100 ml water. Freely sol in alc.

Derivative

Tetramethyl ester.
C14H14O8; mol wt 310.26.
C 54.20%, H 4.55%, O 41.25%.

Properties

Leaflets from alc, mp 141.5°.