The doses inducing hepatic tumours are higher than those inducing cell toxicity. The World Health Organization reports carbon tetrachloride can induce hepatocellular carcinomas (hepatomas) in mice and rats. Īt high temperatures in air, it decomposes or burns to produce poisonous phosgene.Ĭarbon tetrachloride is a suspected human carcinogen based on sufficient evidence of carcinogenicity from studies in experimental animals. CCl 4 has an atmospheric lifetime of 85 years. However, since 1992 its atmospheric concentrations have been in decline for the reasons described above (see atmospheric concentration graphs in the gallery). Ĭarbon tetrachloride is also both ozone-depleting and a greenhouse gas. In 2008, a study of common cleaning products found the presence of carbon tetrachloride in 'very high concentrations' (up to 101 mg/m 3) as a result of manufacturers' mixing of surfactants or soap with sodium hypochlorite (bleach). The effects of carbon tetrachloride on human health and the environment have been assessed under REACH in 2012 in the context of the substance evaluation by France. Chronic exposure to carbon tetrachloride can cause liver and kidney damage and could result in cancer. Exposure to high concentrations of carbon tetrachloride (including vapor) can affect the central nervous system and degenerate the liver and kidneys, and prolonged exposure may lead to coma or death. Safety Ĭarbon tetrachloride is one of the most potent hepatotoxins (toxic to the liver), so much so that it is widely used in scientific research to evaluate hepatoprotective agents. In 1992, production in the U.S./Europe/Japan was estimated at 720,000 tonnes. The production of carbon tetrachloride has steeply declined since the 1980s due to environmental concerns and the decreased demand for CFCs, which were derived from carbon tetrachloride. Prior to the 1950s, carbon tetrachloride was manufactured by the chlorination of carbon disulfide at 105 to 130 ☌: CS 2 + 3 Cl 2 → CCl 4 + S 2Cl 2 Higher chlorocarbons are also subjected to 'chlorinolysis':

The production often utilizes by-products of other chlorination reactions, such as from the syntheses of dichloromethane and chloroform.

With a specific gravity greater than 1, carbon tetrachloride will be present as a dense nonaqueous phase liquid if sufficient quantities are spilled in the environment.Ĭarbon tetrachloride was originally synthesized by the French chemist Henri Victor Regnault in 1839 by the reaction of chloroform with chlorine, but now it is mainly produced from methane: At −47.3 ☌ it has monoclinic crystal structure with space group C2/c and lattice constants a = 20.3, b = 11.6, c = 19.9 (.10 −1 nm), β = 111°. Solid tetrachloromethane has two polymorphs: crystalline II below −47.5 ☌ (225.6 K) and crystalline I above −47.5 ☌. It is somewhat volatile, giving off vapors with a smell characteristic of other chlorinated solvents, somewhat similar to the tetrachloroethylene smell reminiscent of dry cleaners' shops. As a solvent, it is well suited to dissolving other non-polar compounds such as fats and oils. Methane gas has the same structure, making carbon tetrachloride a halomethane. Because of this symmetric geometry, CCl 4 is non-polar. In the carbon tetrachloride molecule, four chlorine atoms are positioned symmetrically as corners in a tetrahedral configuration joined to a central carbon atom by single covalent bonds.

Carbon reactivity