What is Chlorobenzene?

Chlorobenzene is a chemical compound made of carbon, chlorine, and hydrogen. It is alternately referred to as benzene chloride, benzene monochloride, monochlorobenzene, and phenyl chloride. This chemical is most commonly encountered in its liquid form, which is clear. The molecule itself is a ring-shaped aromatic compound.

The physical and chemical properties of chlorobenzene are well-known. It has a boiling point of roughly 132 degrees Celsius (269.6 degrees Fahrenheit), a melting point of about -45.6 degrees Celsius (-50.1 degrees Fahrenheit), a vapor pressure of 1580 Pa, and a molecule weight of 112.6 grams per mole (g/mol). Structurally, it has a molecular formula of C₆H₅Cl, meaning that each molecule of chlorobenzene has six carbon atoms, 5 hydrogen atoms, and one chlorine atom.

Chlorobenzene is classified as an aromatic hydrocarbon. Aromatic hydrocarbons are molecules that form a ring composed of six carbon atoms, called a benzene ring. The carbon molecules in this ring are covalently bonded together, though the bonds themselves constantly alternate between those of the single and double types. Hydrogen atoms are single-bonded to each of the carbon atoms except for the one joined to the chlorine.

Chlorobenzene has been used for many things. It is an industrial solvent for paint, and also a process solvent for adhesives, polishes, and waxes. It can be used to produce nitrochlorobenzene as well as phenol. Chlorobenzene is probably most famous for its use in the production of dichlorodiphenyltrichloroethane (DDT), though this use has decreased significantly since restrictions on DDT were put into place in the 1960s and 1970s.

The chemical can be dangerous to humans. Chlorobenzene is highly flammable, and must be properly stored to avoid fires. Testing has shown that significant exposure can cause damage to the mucous glands, kidneys, and liver; animal testing has also suggested that it can cause testicular degeneration. Some older studies suggest that inhalation of chlorobenzene for many hours straight may cause nervous system damage. Proper protective equipment such as goggles, gloves, and a lab coat should be worn when using chlorobenzene, as well as a respirator mask if the work area is not sufficiently ventilated.