Ethyl chloride is a chemical compound once widely used in producing tetraethyl lead, a gasoline additive. It is a colorless, flammable gas or refrigerated liquid with a faintly sweet odor. Its IUPAC name is monochloroethane or chloroethane.

Production

Ethyl chloride is produced by reacting ethylene and hydrogren chloride over an aluminum chloride catalyst at temperatures ranging from 130-250°C. Under these conditions, ethyl chloride is produced according to the chemical equation.

C₂H₄ + HCl → C₂H₅Cl

At various times in the past, ethyl chloride has also been produced from ethanol and hydrochloric acid, or from ethane and chlorine, but these routes are no longer economical. Some ethyl chloride is generated as a byproduct of polyvinyl chloride production. Should demand for ethyl chloride continue to fall to the point where making it for its own sake is not economical, this may become the leading source of the chemical.

Uses

Beginning in 1922 and continuing through most of the 20th century, the major use of ethyl chloride was to produce tetraethyl lead (TEL), an anti-knock additive for gasoline. However, due to growing awareness of air pollution, TEL has been or is being phased out in most of the industrialized world, and the demand for ethyl chloride has fallen sharply.

Like other chlorinated hydrocarbons, ethyl chloride has been used as a refrigerant, an aerosol propellant, an anesthetic, and a blowing agent for foam packaging. At present though, it is not widely used in any of these roles.

The only remaining industrially important use of ethyl chloride is in treating cellulose to make ethylcellulose, a thickening agent and binder in paints, cosmetics, and similar products.

It is also used by some as a drug because of the symptoms it produces. Sometimes reffered to as "Duster".

Safety

Ethyl chloride is the least toxic of the chloroethanes. Like other chlorinated hydrocarbons, it is a central nervous system depressant, albeit a less potent one than many similar compounds. People breathing its vapors at less than 1% concentration in air usually experience no symptoms. At higher concentrations, victims usually exhibit symptoms similar to those of alcohol intoxication. Breathing its vapors at 15% or higher is often fatal.

Studies on the effects of chronic ethyl chloride exposure in animals have given inconsistent results, and there exists no data for its long-term effects on humans. Some studies have reported that prolonged exposure can produce liver or kidney damage, or uterine cancer in mice, but these data have been difficult to reproduce.

Recent information suggests carcinogenic potential; it has been designated as IARC category A3, Confirmed Animal Carcinogen with Unknown Relevance to Humans. As a result, the State of California has incorporated it into Proposition 65 as a known carcinogen. Nonetheless, it is still used in medicine as a local anesthetic.