| Chemical Abstract Number (CAS #) |
75092
|
|---|
| Synonyms | Methylene chloride |
|---|
Dichloromethane | Methane, dichloro- |
| Analytical Methods |
EPA Method 502.2 |
|---|
EPA Method 524.1 |
EPA Method 524.2 |
EPA Method 601 |
EPA Method 624 |
EPA Method 8010B |
EPA Method 8021A |
EPA Method 8240B |
EPA Method 8260A |
| Use | SOLVENT FOR CELLULOSE ACETATE; MEDICATION: ANESTHETIC
(INHALATION)
PAINT REMOVERS; VAPOR DEGREASING SOLVENT FOR METALS & PLASTICS
SOLVENT & CLEANING AGENT IN THE CHEM PROCESSING INDUST
BLOWING & CLEANING AGENT IN URETHANE FOAM INDUST
IN CHEMICAL PROCESSING & AS CARRIER SOLVENT INSECTICIDES &
HERBICIDES; AS A POST-HARVEST FUMIGANT FOR STRAWBERRIES, AS GRAIN
FUMIGANT, & IN COMBINATION WITH ETHYLENE FOR DEGREENING CITRUS
FRUITS
SOLVENT FOR PLASTIC FILM, ADHESIVES, PROTECTIVE COATINGS; CLEANING
SOLVENT FOR CIRCUIT BOARDS & STRIPPER SOLVENT FOR PHOTORESISTS
IN PHARMACEUTICAL INDUSTRY AS A PROCESS SOLVENT IN PRODN OF
STEROIDS, ANTIBIOTICS & VITAMINS & SOLVENT FOR TABLET COATINGS
DECAFFEINATING COFFEE; EXTRACTION OF HEAT-SENSITIVE SUBSTANCES SUCH
AS COCOA, EDIBLE FATS, SPICES & BEER HOPS
REFRIGERANT; IN OIL DEWAXING; AS DYE & PERFUME INTERMEDIATE; AS
CARRIER SOLVENT IN TEXTILE INDUSTRY
COMPONENT OF FIRE EXTINGUISHING CMPD
CHEM INT FOR BROMOCHLOROMETHANE & OTHER CHEMICALS
In furniture processing
In pour molding of dental material, the 50:50 mixture of dichloromethane and methylmethacrylate
cold curing monomer is used to treat the acrylic teeth to improve the bonding
Ingredient in nonflammable removers, strippers, & cements; used in aerosol formulations; in solid
phase peptide synthesis; solvent for resins
Low temp heat transfer medium
|
|---|
| Consumption Patterns | Paint removers, 30%; metal cleaning/degreasing, 22%; miscellaneous solvent uses and
other applications, 21%; aerosols, 17%; foam blowing agent, 5%; pharmaceutical solvent, 5%
(1978). From table
PAINT REMOVER, 30%; AEROSOLS, 20%; VAPOR DEGREASING, 11%; CHEM
PROCESS INDUST, 11%; BLOWING AGENT, 6%; FILM PROCESSING, 6%; PLASTICS
PROCESSING, 6%; PHARMACEUTICALS, 6%; OTHER, 4% (1981)
Demand: 1982: 530 million lb; 1983: 530 million lb; 1987: 621 million lb.
Aerosols, 30%; paint remover, 30%; foam blowing, 15%; fiber & plastic solvent, 5%; metal
cleaning, 5%; miscellaneous, 15% (1985)
CHEMICAL PROFILE: Methylene chloride. Paint stripper, 28%; aerosols, 18%; exports, 15%;
chemical processing, 11%; urethane foam blowing agent, 9%; metal degreasing, 8%; electronics,
7%; other, 4%.
CHEMICAL PROFILE: Methylene chloride. Demand: 1988: 500 million lb; 1989: 475 million lb;
1993 projected/: 410 million lb. (Includes exports, but not imports, which totaled 27 million lb
last year).
|
|---|
| Apparent Color | COLORLESS LIQ
|
|---|
| Odor | Sweet, pleasant odor, like chloroform
|
|---|
| Boiling Point | 39.75 DEG C @ 760 MM HG
|
|---|
| Odor Threshold Concentration | 205-307 ppm
2.14x10 2 ppm (odor recognition in air; chemically pure sample)
Odor thresholds: low= 540 mg/cu m; high= 2160 mg/cu m.
Odor index: 2100 @ 20 deg C
|
|---|
| Sensitivity Data | Irritation of eyes and respiratory tract.
|
|---|
| Environmental Impact | Large quanitities of dichloromethane are used each year, primarily in aerosols, paint
removers and chemial processing. The major route of human exposure is from air, which can be
high near sources of emission, and contaminated drinking water. Most of the dichloromethane will
be released to the atmosphere where it will degrade by reaction with photochemically produced
hydroxyl radicals with a half-life of a few months. It will be subject to direct photolysis. Releases
to water will primarily be removed by evaporation. Biodegradation is possible in natural waters
but will probably be very slow compared with evaporation. It will not be expected to significantly
adsorb to sediment or to bioconcentration in aquatic organisms. Releases to soil will evaporate
rapidly from near-surface soil and partially leach into groundwater where its fate is unknown.
Dichloromethane is not expected to bioconcentrate in the food chain,
|
|---|
| Environmental Fate | TERRESTRIAL FATE: When spilled on land, dichloromethane is expected to evaporate
from near surface soil into the atmosphere because of its high vapor pressure. Although little
work has been done on its adsorptivity, it is probable that it will leach through subsoil into
groundwater. Degradation in groundwater is unknown. Hydrolysis in soil or groundwater is not
an important process under normal environmental conditions .
AQUATIC FATE: Dichloromethane will be primarily lost by evaporation to the atmosphere
which should take several hours depending on wind and mixing conditions. When released into a
river, dichloromethane levels were non-detectable 3-15 miles from the source(1-2).
Biodegradation is possible in natural waters but will probably be very slow compared with
evaporation . Little is known about adsorption or bioconcentration in aquatic organisms to
sediment but these are not likely to be significant processes. Hydrolysis is not an important
process under normal enivronmental conditions .
ATMOSPHERIC FATE: Dichloromethane released into the atmosphere will degrade by reaction
with hydroxyl radicals with a half life of several months(1-3). It will not be subject to direct
photolysis . A small fraction of the chemical will diffuse to the stratosphere where it will rapidly
degrade by photolysis and reaction with chlorine radicals(1,5). A moderately soluble chemical
such as dichloromethane will be expected to partially return to earth in rain.
|
|---|
| Drinking Water Impact | DRINKING WATER: 30 Canadian Water Treatment Facilities - 50% positive - 10 ppb,
avg, 50 ppb max (summer), 30% pos, 3 ppb avg, 50 ppb max (winter) ; 10 State survey
drinking water from groundwater sources - 2% pos, 3600 ppb max, max surface water conc 13
ppb ; EPA Region V Survey (83 sites in 5 states: MN, WI, IL, IN, OH) - 8% pos, 1-7 ppb ,
National Organics Monitoring Survey (1976) - 15 of 109 samples positive, 6.1 ppb, mean of
positive samples .
EFFL: Weser R, Germany - 72-179 ppb . Industries in which wastewater exceeded an average
of 1000 ppb: Coal mining, aluminum forming, photographic equipment and supplies,
pharmaceutical mfg, organic chemical plastics mfg, paint and ink formulation, rubber processing,
foundries, and laundries . Max concentration measured was 210,000 ppb in paint and ink
industry and aluminum forming . Outfalls from 4 municipal treatment plants in southern
California with primary or secondary treatment - random samples - < 10 to 400 ppb . USEPA
STORET database, 1,480 data points, 38.8% pos, 10.0 ppb median . USA, 178 CERCLA
hazardous waste disposal sites, 19.2% pos . Minnesota municipal solid waste landfills,
leachates, 6 sites, 66.7% pos, 64-1300 ppb, contaminated groundwater (by inorganic indices), 13
sites, 53.8% pos, 1-250 ppb, other groundwater (apparently not contaminated as indicated by
inorganic indices), 7 sites, 14.3% pos, 2.1-3.9 ppb(6).
Water samples collected in Feb & May 1977 from Back River estuary in MD, USA, which
received effluent from an urban wastewater treatment plant, contained dichloromethane. The
highest levels (66 ug/l) were found in samples taken in the treatment plant just before final
chlorination, suggesting that dichloromethane was derived from commercial & industrial activities
in the area.
Dichloromethane was detected @ levels ranging from 19-95 ug/l in 6 samples of raw sewage &
effluent from Canadian sewage treatment plants. Wastewater from a USA specialty chemical plant
manufacturing a broad range of chemicals container 3-8 mg/l dichloromethane.
Dichloromethane was detected at concn ranging from < 0.01 to 1.0 mg/l in volatile fraction of
wastewater from Oak Ridge Gaseous Plant in TN, USA. As part of the Swedish Drinking Water
Project, dichloromethane was found at 640 ug/l in effluent stream from sulfate pulp mill. The amt
of dichloromethane discharged was est to be 40 ton/yr.
|
|---|
