COAL TAR

Chemical properties

The term “coal tar products,” as used by NIOSH, includes coal tar and two of the fractionation products of coal tar, creosote and coal tar pitch, derived from the carbonization of bituminous coal. Coal tar, coal tar pitch, and creosote (coal tar creosote 8001-58-9) derived from bituminous coal often contain identifiable components which by themselves are carcinogenic, such as benzo(a) pyrene, benzanthracene, chrysene, and phenanthrene. Other chemicals from coal tar products, such as anthracene, carbazole, fluoranthene, and pyrene may also cause cancer,but these causal relationships have not been adequately documented. Also, the research chemical methylcholanthrene (CAS: 56-49-5), a powerful carcinogen, fits this category. Coal tar pitch is a black viscous liquid. Aromatic solvent odor. Boiling point =>260°C; specific gravity (H2O:1) = 1.07-108; freezing/melting point = 250-°180C;flash point = 207°C (coal tar pitch); 74C (creosote oil);autoignition temperature =>510°C. Insoluble in water.Coal tar creosote (8001-58-9, crosote) is an black oily,tar-like substance. Pungent odor

The Uses of COAL TAR

This substance is a mixture of many individual substances and cannot be adequately represented by a single molecuIar structure. Coal tar is a by-product in the distillation of coal. May cause postinflammatory hyperpigmentation. It is a topical antieczematic agent.

Definition

The distillate from coal tar having an approximate distillation range of 100.degree.C to 450.degree.C (212.degree.F to 842.degree.F). Composed primarily of two to four membered condensed ring aromatic hydrocarbons, phenolic compounds, and aromatic nitrogen bases.

General Description

Black viscous liquid with an odor of aromatic solvent.

Reactivity Profile

Vigorous reactions, sometimes amounting to explosions, can result from the contact between aromatic hydrocarbons and strong oxidizing agents. They can react exothermically with bases and with diazo compounds. Substitution at the benzene nucleus occurs by halogenation (acid catalyst), nitration, sulfonation, and the Friedel-Crafts reaction.

Health Hazard

EYES: Redness, irritation, blurred vision. INHALATION: Nasal and respiratory irritation, fatigue, dizziness, weakness, headache, and possible cardiovascular collapse. INGESTION: Gastrointestinal irritation, nausea, vomiting, and diarrhea. SKIN: Can cause severe irritation, which, when accentuated by sunlight, may result in phototoxic burns.

Fire Hazard

Special Hazards of Combustion Products: Toxic gases, such as carbon monoxide, may be produced.

Safety Profile

A carcinogen. A flammable liquid. When heated to decomposition it emits acrid smoke and irritating vapors.

Potential Exposure

The coke-oven plant is the principal source of coal tar. The hot gases and vapors produced during the conversion of coal to coke are collected by means of a scrubber, which condenses the effluent into ammonia, water, crude tar, and other by-products. Crude tar is separated from the remainder of the condensate for refining and may undergo further processing. Employees may be exposed to pitch and creosote in metal and foundry operations; when installing electrical equipment; in construction, railway, utility; and briquette manufacturing.

Shipping

UN1136 Coal tar distillates, flammable, Hazard Class: 3; Labels: 3-Flammable liquid

Incompatibilities

Incompatible with strong oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides. Phenols, such as creosote react as weak organic acids. Phenols and cresols are much weaker as acids than common carboxylic acids (phenol has pKa = 9.88). These materials are incompatible with strong reducing agents such as hydrides, nitrides, alkali metals, and sulfides. Flammable hydrogen gas is often generated, and the heat of the reaction may ignite the gas. Heat is also generated by the acid-base reaction between phenols and bases. Such heating may initiate polymerization of the organic compound. Phenols are sulfonated very readily (e.g., by concentrated sulfuric acid at room temperature). The reactions generate heat. Phenols are also nitrated very rapidly, even by dilute nitric acid

Waste Disposal

Dissolve or mix the material with a combustible solvent and burn in a chemical incinerator equipped with an afterburner and scrubber. All federal, state, and local environmental regulations must be observed.