7371. Phthalic Acid

Nomenclature

CAS number: 88-99-3
1,2-Benzenedicarboxylic acid.
C8H6O4; mol wt 166.13.
C 57.84%, H 3.64%, O 38.52%.

Description and references

Manufactured by catalytic oxidation of o-toluic acid and oxidation of xylene: Taylor, Dean, US 3064046 (1962 to I.C.I.); Cier, US 3088974 (1963 to Esso Res. & Eng.). Isoln from the fungus, Gibberella fujikuroi: Cross et al., J. Chem. Soc. 1963, 2937. Toxicity studies: C. B. Shaffer et al., J. Ind. Hyg. Toxicol. 27, 130 (1945); A. R. Singh et al., J. Pharm. Sci. 61, 59 (1972). Review of toxicology: A. M. Api, Food Chem. Toxicol. 39, 97-108 (2001).

Chemical structure

Properties

Crystals, mp ≈230° when rapidly heated, forming phthalic anhydride and water. One gram dissolves in 160 ml water, 10 ml alc, 205 ml ether, 5.3 ml methanol. Practically insol in chloroform. LD50 orally in rats: 7.9 g/kg (Shaffer).

Derivative

Ethyl ester.

Nomenclature

CAS number: 84-66-2
Ethyl phthalate; diethyl phthalate; Neantine (Givaudan); Palatinol A (Advanced Solvents).
C12H14O4; mol wt 222.24.
C 64.85%, H 6.35%, O 28.80%.

Description and references

Review of toxicology and human exposure: Toxicological Profile for Diethyl Phthalate (PB95-264214, 1995) 159 pp.

Properties

Colorless, practically odorless, oily liq; bitter disagreeable taste. d414 1.232. bp 295°. Flash pt 140°C. nD14 1.5049. Insol in water. Misc with alcohol, ether and many other organic solvents. LD50 i.p. in rats: 5.06 ml/kg (Singh).

Caution

Potential symptoms of overexposure to diethyl phthalate are irritation of eyes, skin, nose, throat; headache, dizziness, nausea; lacrimation; polyneuritis, vestibular dysfunction; pain, numbness, weakness, spasms in arms and legs. See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 108.

Use

Phthalic acid used in buffers. Ethyl phthalate used in manuf celluloid; solvent for cellulose acetate in manuf varnishes and dopes; denaturing alc. Vehicle for fragrance and cosmetic ingredients.