| Chemical Abstract Number (CAS #) |
74884
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| Synonyms | Iodomethane |
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Methyl iodide | Methane, iodo |
| Analytical Methods |
EPA Method 524.2 |
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EPA Method 8010B |
EPA Method 8240B |
EPA Method 8240B |
EPA Method 8260A |
EPA Method 8260A |
| Molecular Formula | CH3I |
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| Use | IN METHYLATIONS; IN MICROSCOPY BECAUSE OF HIGH REFRACTIVE
INDEX; AS IMBEDDING MATERIAL FOR EXAMINING DIATOMS; IN TESTING FOR
PYRIDINE
USED AS METHYLATING AGENT IN PREPN OF PHARMACEUTICAL
INTERMEDIATES
CHEM INTERMED FOR METHYLAMINES & QUATERNARY AMMONIUM IODIDES
CHEM INTERMED FOR QUATERNARY PHOSPHONIUM IODIDES
CHEM INTERMED FOR ORGANOMETALLICS, EG, METHYL MERCURIC IODIDE
Used as a fire extinguisher .
Methyl iodide has been investigated in India for use as a fumigant to control internal fungi of grain
sorghum.
REACTS WITH MANY CMPD AS ALKYLATING AGENT
Used as building block for radioactive tracers synthesis. Methyl iodide (14C) is used for
carbon-14-labeled compounds methyl iodide (3H) is used for tritium-labeled compounds p.634]
Reacts with dimethyl ethyl amine to yield quaternary ammonium compounds
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| Apparent Color | COLORLESS, TRANSPARENT LIQUID
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| Odor | PUNGENT ODOR ; SWEET ETHERAL ODOR
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| Boiling Point | 42.5 DEG C
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| Melting Point | -66.5 DEG C
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| Molecular Weight | 141.94
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| Density | 2.28 @ 20 DEG C/4 DEG C
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| Sensitivity Data | Eye irritant; can blister the skin.
Lung irritation from acute exposure. Prolonged contact with skin can cause vesicant burns.
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| Environmental Impact | Methyl iodide is produced by many marine photosynthetic organisms and therefore the
surface ocean is thought to be a major natural source of methyl iodide. Some of this will exchange
into the atmosphere and some will react with seawater (half-life approximately 20 days at 19 deg
C) to form methyl chloride. It will not be expected to sorb to soil or sediment, or to
bioconcentrate in aquatic organisms; however, there is some evidence of bioaccumulation in
marine animals. In the atmosphere, methyl iodide degrades (half-life 3-7 hr). Humans are exposed
to methyl iodide from the ambient air and from ingesting seafood from the ocean. .
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| Environmental Fate | TERRESTRIAL FATE: If spilled on land, methyl iodide would be expected to volatize
rapidly. It will not be expected to sorb to soils. No studies could be found concerning its fate on
land but it could photolyze or decompose by reacting with chlorides.
AQUATIC FATE: Methyl iodide will be removed from the water by volatilization (half-life 3.6 hr
in a typical river). In the ocean methyl iodide will react with chloride to form methyl chloride
(methyl iodide half-life 20 and 58 days at 19.2 and 10.8 deg C, respectively). In placid bodies of
fresh water, hydrolysis of methyl iodide may be significant (half-life 100-251 days). Photolysis
may also be important but there is no data with which to evaluate its extent. It will not be
expected to bind to sediments or to bioconcentrate in aquatic organisms; however, there is some
evidence of bioaccumulation in marine animals.
ATMOSPHERIC FATE: Methyl iodide photolyzes in air with a half-life of 7 hr and less under
smog situations.
Aquatic Fate: In seawater, iodomethane can react with chloride ion to yield chloromethane, and
this reaction occurs as fast as the exchange of iodomethane into the atmosphere (exchange rate,
4x10-7/sec). The monohalomethanes are not oxidized readily under ordinary conditions.
Atmospheric Fate: Monohalomethanes undergo photolysis in the upper atmosphere where
ultraviolet radiation is of sufficient energy to initiate a reaction. Monohalomethanes
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| Drinking Water Impact | SEAWATER: Point Reyes, CA - nearshore 37 parts/trillion . Atlantic Ocean surface
water 135 parts/trillion .
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