MOLECULE

Methylene chloride

Methylene chloride also known as dichloromethane, belongs to the class of organic compounds known as halomethanes. These are organic compounds in which at least one of the four hydrogen atoms of methane (CH4) are replaced by halogen atoms. Dichloromethane is an organochloride compound with the formula CH2Cl2. This colorless, volatile liquid with a moderately sweet aroma is widely used as a solvent. Although it is not miscible with water, it is polar, and miscible with many organic solvents. Natural sources of dichloromethane include oceanic sources, macroalgae, wetlands, and volcanoes. However, the majority of dichloromethane in the environment is the result of industrial emissions. The output of these processes is a mixture of methyl chloride, dichloromethane, chloroform, and carbon tetrachloride. It is used as a diluent for colour additives and inks for marking fruit and vegetables. In the food industry, it has been used to decaffeinate coffee and tea as well as to prepare extracts of hops and other flavorings. Its volatility has led to its use as an aerosol spray propellant and as a blowing agent for polyurethane foams. Dichloromethane is formally rated as a probable carcinogen (by IARC 2A) and is also a potentially toxic compound. Exposure to dichloromethane may cause optic neuropathy and hepatitis. Very high concentrations can lead to unconciousness, coma, and death. Even though it is not expected to naturally occur in plants, methylene chloride has been reported as a volatile compound detected in cannabis samples obtained through police seizure (PMID: 26657499).