9249. Tetroquinone

Nomenclature

CAS number: 319-89-1
2,3,5,6-Tetrahydroxy-2,5-cyclohexadiene-1,4-dione; tetrahydroxy-p-benzoquinone; tetrahydroxyquinone; THQ; HPEK-1; NSC-112931.
C6H4O6; mol wt 172.09.
C 41.88%, H 2.34%, O 55.78%.

Description and references

Prepn from glyoxal: A. J. Fatiadi, W. F. Sager, Org. Synth. coll. vol. V, 1011 (1973). Clinical evaluation for ophthalmic fibrosis: R. Ching, Eye Ear Nose Throat Mon. 50, 101, 144 (1971).

Chemical structure

Properties

Dark, odorless, tasteless crystals with blue-black metallic luster in reflected light. mp 280°. Sol (1:200) in cold water; sol (1:100) in hot water or in alcohol; slightly sol in ether. It acts like a strong dibasic acid.

Derivative

Disodium salt.
Na2C6H2O6; mol wt 216.06.
Na 21.28%, C 33.35%, H 0.93%, O 44.43%.

Properties

Almost black crystals with a green metallic luster, sparingly sol in water.

Use

Disodium salt is used as an indicator in the volumetric determination of sulfate by means of barium chloride solution.