Chemical name. Coal tar; CAS Reg. No. 8007-45-2.

Description. Brown-black or black, viscous liquid; odour, characteristic and strong resembling naphthalene.

Solubility. Slightly soluble in water; very slightly or partially soluble in ethanol (~750 g/l) TS, ether R, and hexane R.

Category. Keratoplastic agent.

Storage. Coal tar should be kept in a tightly closed container.

Additional information. Coal tar bums in air with a luminous sooty flame. On exposure to air it hardens. Even in the absence of light, it is gradually degraded on exposure to a humid atmosphere, the decomposition being faster at higher temperatures.

Requirements

Definition. Coal tar is a by-product usually obtained during the destructive distillation of coal. It is a complex and undefined mixture of a great number of chemical compounds. The product is available in various compositions.

Identity test

Carefully add 0.5 g to 10 mL of light petroleum R1 and allow to stand for 30 minutes; the supernatant liquid has a blue fluorescence in daylight and a more intense fluorescence when viewed in ultraviolet light (365 nm).

Sulfated ash. Not more than 20 mg/g.