3D model (JSmol)
CompTox Dashboard (EPA)
|Odor||Faint, sweet odor|
|Density||1.003 g/mL (-23.8 °C, liquid) 2.3065 g/L (0 °C, gas)|
|Melting point||-97.4 °C (-143.3 °F; 175.8 K)|
|Boiling point||-23.8 °C (-10.8 °F; 249.3 K)|
|5.325 g L-1|
|Vapor pressure||506.09 kPa (at 20 °C (68 °F))|
|940 nmol Pa-1 kg-1|
|234.36 J K-1 mol-1|
Std enthalpy of
|-83.68 kJ mol-1|
Std enthalpy of
|-764.5--763.5 kJ mol-1|
|Safety data sheet||See: data page|
|GHS Signal word||Danger|
|H220, H351, H373|
|P210, P281, P410+403|
|NFPA 704 (fire diamond)|
|Flash point||-20 °C (-4 °F; 253 K)|
|625 °C (1,157 °F; 898 K)|
|Lethal dose or concentration (LD, LC):|
LD50 (median dose)
|1800 mg/kg (oral, rat)|
5.3 mg/L/4 h (inhalation, rat)
LC50 (median concentration)
|72,000 ppm (rat, 30 min)|
2200 ppm (mouse, 6 hr)
2760 ppm (mammal, 4 hr)
2524 ppm (rat, 4 hr)
LCLo (lowest published)
|20,000 ppm (guinea pig, 2 hr)|
14,661 ppm (dog, 6 hr)
|NIOSH (US health exposure limits):|
|TWA 100 ppm C 200 ppm 300 ppm (5-minute maximum peak in any 3 hours)|
IDLH (Immediate danger)
|Ca [2000 ppm]|
|Supplementary data page|
|Refractive index (n),|
Dielectric constant (?r), etc.
|UV, IR, NMR, MS|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|what is ?)(|
Chloromethane, also called methyl chloride, Refrigerant-40, R-40 or HCC 40, is an organic compound with the chemical formula CH3Cl. One of the haloalkanes, it is a colorless, odorless, flammable gas. Methyl chloride is a crucial reagent in industrial chemistry, although it is rarely present in consumer products.
Laboratory cultures of marine phytoplankton (Phaeodactylum tricornutum, Phaeocystis sp., Thalassiosira weissflogii, Chaetoceros calcitrans, Isochrysis sp., Porphyridium sp., Synechococcus sp., Tetraselmis sp., Prorocentrum sp., and Emiliana huxleyi) produce CH3Cl, but in relatively insignificant amounts. An extensive study of 30 species of polar macroalgae revealed the release of significant amounts of CH3Cl in only Gigartina skottsbergii and Gymnogongrus antarcticus.
The salt marsh plant Batis maritima contains the enzyme methyl chloride transferase that catalyzes the synthesis of CH3Cl from S-adenosine-L-methionine and chloride. This protein has been purified and expressed in E. coli, and seems to be present in other organisms such as white rot fungi (Phellinus pomaceus), red algae (Endocladia muricata), and the ice plant (Mesembryanthemum crystallinum), each of which is a known CH3Cl producer.
Chloromethane has been detected in the low-mass Class 0 protostellar binary, IRAS 16293-2422, using the Atacama Large Millimeter Array (ALMA). It was also detected in the comet 67P/Churyumov-Gerasimenko (67P/C-G) using the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) instrument on the Rosetta spacecraft. The detections reveal that chloromethane can be formed in star-forming regions before planets or life is formed.
Chloromethane was first synthesized by the French chemists Jean-Baptiste Dumas and Eugene Peligot in 1835 by boiling a mixture of methanol, sulfuric acid, and sodium chloride. This method is similar to that used today.
A smaller amount of chloromethane is produced by treating a mixture of methane with chlorine at elevated temperatures. This method, however, also produces more highly chlorinated compounds such as dichloromethane, chloroform, and carbon tetrachloride. For this reason, methane chlorination is usually only practiced when these other products are also desired. This chlorination method also cogenerates hydrogen chloride, which poses a disposal problem.
Most of the methyl chloride present in the environment ends up being released to the atmosphere. After being released into the air, the life of this substance in the atmosphere varies from one to three years.
On the other hand, when the methyl chloride emitted is released to water, it will be rapidly lost by volatilization. The [half-life] of this substance in terms of volatilization in the river, lagoon and lake is 2.1 h, 25 h and 18 days, respectively.
Large scale use of chloromethane is for the production of dimethyldichlorosilane and related organosilicon compounds. These compounds arise via the direct process. The relevant reactions are (Me = CH3):
Dimethyldichlorosilane (Me2SiCl2) is of particular value (precursor to silicones, but trimethylsilyl chloride (Me3SiCl) and methyltrichlorosilane (MeSiCl3) are also valuable. Smaller quantities are used as a solvent in the manufacture of butyl rubber and in petroleum refining.
Chloromethane is employed as a methylating and chlorinating agent, e.g. the production of methylcellulose. It is also used in a variety of other fields: as an extractant for greases, oils, and resins, as a propellant and blowing agent in polystyrene foam production, as a local anesthetic, as an intermediate in drug manufacturing, as a catalyst carrier in low-temperature polymerization, as a fluid for thermometric and thermostatic equipment, and as a herbicide.
Chloromethane was a widely used refrigerant, but its use has been discontinued. Chloromethane was also once used for producing lead-based gasoline additives (tetramethyllead).