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Chloromethane, frequently called methyl chloride, is a colorless, toxic gas. It has been known since the early 19th century.
In 1835, prominent French chemists Jean-Baptiste Dumas of the 脡cole Polytechnique and Eug猫ne P茅ligot of the Institut National Agronomique (both in Paris) teamed up to devise the first synthesis of chloromethane. They heated methanol and sodium chloride in the presence of sulfuric acid to produce the gas. Their synthesis was the forerunner of the primary modern manufacturing method, which uses hydrogen chloride in place of NaCl and H2SO4.
Chloromethane is found sparsely in nature. It is usually produced by the enzyme methyl chloride tranferase, which is present in wood-rotting fungi and salt marsh plants. As of 2020, chloromethane was the , by both the Atacama Large Millimeter/submillimeter Array telescope in Chile and the Rosetta spacecraft.
Chloromethane was once widely used as a refrigerant1, but it has long since been replaced by substances that are less toxic and less harmful to the ozone layer in Earth鈥檚 atmosphere. Currently, it is used in industry as a reagent in chemical production, an extractant for oils and resins, a propellant in foam production, and a solvent in rubber manufacture and petroleum refining.
1. As a refrigerant, chloromethane was called Freon-40.
Chloromethane hazard information
Hazard class* | GHS code and hazard statement | |
---|---|---|
Flammable gases, category 1 | H220鈥擡xtremely flammable gas | ![]() |
Gases under pressure (liquefied gas), category 3 | H280鈥擟ontains gas under pressure; may explode if heated听 | ![]() |
Carcinogenicity, category 2 | H351鈥擲uspected of causing cancer | ![]() |
Reproductive toxicity, category 2 | H361鈥擲uspected of damaging fertility or the unborn child | ![]() |
Specific target organ** toxicity, repeated exposure, inhalation, category 2 | H373鈥擟auses damage to organs through prolonged or repeated exposure if inhaled | ![]() |
*Globally Harmonized System (GHS) of Classification and Labeling of Chemicals.听
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**Central nervous system, liver, and/or urogenital tract.
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Chloromethane
fast facts
CAS Reg. No. | 74-87-3 |
nomenclature | Methane, chloro- |
Empirical formula | CH3Cl |
Molar mass | 50.49 g/mol |
Appearance | Colorless gas |
Boiling point | 鈥�24 掳C |
Water solubility | 5.3 g/L |

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