Chemical Fact Sheet

Chemical Abstract Number (CAS #) 74873
CASRN 74-87-3
Methyl chloride
Methane, chloro
Analytical Methods EPA Method 502.2
EPA Method 524.2
EPA Method 601
EPA Method 624
EPA Method 8010
EPA Method 8021
EPA Method 8260
Molecular FormulaCH3Cl

Link to the National Library of Medicine's Hazardous Substances
Database for more details on this compound.

Use MEDICATION: LOCAL ANESTHETIC As aerosol propellant (former use) FOAMING AGENT IN PLASTICS INDUSTRY; IN STAINLESS STEEL INDUSTRY IN MFR OF TETRAMETHYL LEAD, METHYL CELLULOSE, FUMIGANTS, SYNTHETIC RUBBER; ALSO AS A METHYLATING AGENT, PROPELLANT, AND HERBICIDE FLUID FOR THERMOMETRIC & THERMOSTATIC EQUIPMENT EXTRACTANT FOR OILS, FATS AND RESINS CHEM INT (UNISOLATED) FOR METHYLENE CHLORIDE & CHLOROFORM, CHEM INT FOR METHYLARSONATE HERBICIDES, QUATERNARY AMMONIUM CHLORIDES, METHYL MERCAPTAN; SOLVENT & DILUENT IN PRODN OF BUTYL RUBBER. Methyl chloride is primarily used to produce silicone resins and rubbers. Methyl chloride is used to terminate the polymerization of bakelite polysulfone. This controls the molecular weight of the polymer and contributes to thermal stability Timber products processing Blowing agent for some polystyrene foams. As a refrigerant
Consumption Patterns CHEM INT FOR METHYLCHLOROSILANES, 76%; CHEM INT FOR TETRAMETHYL LEAD, 9%; SOLVENT & DILUENT IN PRODN OF BUTYL RUBBER, 3%; CHEM INT FOR OTHER CHEMS, EG, METHYL CELLULOSE, METHYLARSONATES, 12% (1981- EXCLUDES CHEM INT FOR METHYLENE CHLORIDE & CHLOROFORM) Silicones, 72%; agricultural chemical, 8%; methyl cellulose, 6%; quaternary amines, 5%; butyl rubber, 3%; miscellaneous, including tetramethyl lead, 2%; export, 4% (1983) CHEMICAL PROFILE: Methyl Chloride. Silicones, 74%; agricultural chemicals, 7%; methyl cellulose, 6%; quaternary amines, 5%; butyl rubber, 2%; miscellaneous, 2%; exports, 4%. (1987)] CHEMICAL PROFILE: Methyl chloride. Demand: 1988: 540 million lb; 1989: 550 million lb; 1993 projected/: 580 million lb. (Includes exports, but not imports, which are negligible). (1989)]
Odor ETHEREAL ODOR (LIQUID) ; Faint, sweet odor
Boiling Point -23.7 DEG C
Melting Point -97 DEG C
Molecular Weight 50.49
Density 0.9159 @ 20 DEG C/4 DEG C
Odor Threshold Concentration Odor recognition in air: 1.00x10 1 ppm (chemically pure) Odor not noticeable at dangerous concentrations. Odor Threshold (air) 21 mg/cu m
Sensitivity Data Vapor: Not irritating to eyes, nose or throat. Liquid: Will cause frostbite. Threshold of irritation: 1050 mg/cu m. From table
Environmental Impact Methyl chloride is produced naturally in the oceans by mechanisms which are not entirely understood. One source is believed to be the reaction of biologically produced methyl iodide with chloride ions. Other significant natural sources include forest and brush fires and volcanoes. Although the atmospheric budget of methyl chloride can be accounted for by volatilization from the oceanic reservoir, it is apparent that man-made sources arising from its production and use in the manufacture of silicones and other chemicals and as a solvent and propellant can make a significant impact on the local atmospheric concn of methyl chloride. If released into water, methyl chloride will be rapidly lost by volatilization (half-life in a typical river 2.1 hr). It will also be rapidly lost from soil by volatilization although there is a potential for it to leach into groundwater where it may very slowly biodegrade and hydrolyze (half-life may exceed a yr). Once in the atmosphere it will disperse and will be lost primarily by upward dispersion. Above the tropopause, reaction with hydroxyl radicals aid in the removal of methyl chloride and above 30 km, photodissociation, diffusion and reaction with hydroxyl radicals make roughly equal contributions to its removal. Humans are exposed to methyl chloride from the ambient air via inhalation.
Environmental Fate ATMOSPHERIC FATE: The dominant loss mechanism for methyl chloride in the troposphere is upward diffusion although washout by rain may also be important. From the tropopause to about 30 km, both upward diffusion and reaction with hydroxyl radicals will be of approximately equal importance, and above 30 km in the stratosphere diffusion, reaction with hydroxyl radicals, and photodissociation will have approximately equal weight . The surface half-life resulting from upward diffusion is 80 days(1,SRC). AQUATIC FATE: If methyl chloride is released into water, it will be lost primarily by volatilization (half-life 2.1 hr in a typical river). TERRESTRIAL FATE: Methyl chloride has a very high vapor pressure and if released on land will be rapidly lost by volatilization. It may also leach into groundwater where it should very slowly biodegrade or hydrolyze. Waste water treatment: evaporation from water at 25 deg C of a 1 ppm solution: 50% after 27 min, 90% after 91 min
Drinking Water Impact DRINKING WATER: Treated water from 30 Canadian potable water treatment facilities - 2 samples pos, mean (5 ppb) . Drinking water well in Maine reported in a Council on Environmental Quality survey of contaminated drinking water from groundwater sources 44 ppb . Highest reported concn of methyl chloride in surface water derived drinking water 12 ppb . Identified, not quanitified in drinking water in New Orleans, Cincinnati, Miami, Philadelphia, and Ottumwa, IA of the 10 cities surveyed . Not detected (DL 0.1 ppb) in treated water at 10 water treatment plants (42 samples) using Great Lakes water . GROUNDWATER: Detected, not quantified in 11 of 20 groundwaters underlying municipal solid waste landfills in MN . SURFACE WATER: 895 stations in the USEPA STORET data base 1.4% pos, median < 10 ppb . Raw water from 30 Canadian potable water treatment facilities - 1 sample pos, mean < 5 ppb . Detected in the Niagara River and the open water of Lake Ontario . Not detected (DL 0.1 ppb) in raw water at 10 water treatment plants (42 samples) using Great Lakes water . SEAWATER: Pacific Ocean 26.8 parts per trillion at surface, 3.3 parts per trillion at 300 m depth . Eastern Pacific surface water (latitude 29 deg N to -29 deg S) 6.3-42 parts per trillion, 11.5 parts per trillion mean, 200-300% supersaturation . Point Reyes, CA (nearshore) 1200 parts per trillion . EFFL: 1298 stations in the USEPA STORET data base 3.5% pos, median < 10 ppb . Detected in 1 of 5 leachates from municipal waste landfills in WI 170 ppb and detected, not quantified in 4 of 6 leachates from municipal landfills in MN . Methyl chloride has been detected in treated wastewater from the following industries (industry (mean concn)): pharmaceutical manufacturing (2000 ppb), organic chemical manufacturing/plastics (0.1 ppb), timber products processing (140 ppb) and raw wastewater from metal finishing (610 ppb) . Ratios of methyl chloride (ppmv) to carbon dioxide (1X10-6 ppmv) in wood smoke ranged from 0.66 to 2.63 . In a comprehensive survey of wastewater from 4000 industrial and publicly owned treatment works (POTWs) sponsored by the Effluent Guidelines Div of the U.S. EPA, methyl chloride was identified in discharges of the following industrial categories (frequency of occurrence, median concn in ppb): nonferrous metals (1; 21.6), paint and ink (2; 4128.7), printing and publishing (1; 6.0), organics and plastics (1; 156.7), pharmaceuticals (1; 2558.3), organic chemicals (3; 49.0) . The highest effluent conc was 4194 ppb in the paint and ink industry .

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