light yellow to light pink liquid
ChEBI: A member of the class of iodomethanes that is methane in which one of the hydrogens is replaced by iodine.
Halogenated aliphatic compounds, such as Iodomethane, are moderately or very reactive. Reactivity generally decreases with increased degree of substitution of halogen for hydrogen atoms. Low molecular weight haloalkanes are highly flammable and can react with some metals to form dangerous products. Materials in this group are incompatible with strong oxidizing and reducing agents. Also, they are incompatible with many amines, alkylphosphines, nitrides, azo/diazo compounds, alkali metals (sodium), and epoxides.
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Methyl bromide is scheduled for elimination as a soil fumigant and iodomethane has been proposed as an alternative[15-18]. Based on the atmospheric lifetime, global warming potential, and ozone depletion potential, the U.S. Environmental Protection Agency(USEPA) has identified iodomethane as a reduced risk alternative to methyl bromide.
In October, 2007, the USEPA issued a one year time-limited registration of iodomethane. In April 2009, USEPA extended conditional registration of iodomethate without specifying any time limits. The USEPA website provides details of the registration. An application for California registration is currently being evaluated by DPR. Due to its acute toxicity, proposed products containing iodomethane are labeled as restricted use pesticides.
Methyl iodide deteriorates rapidly with liberation of iodine if exposed to light. It is usually purified by shaking with dilute aqueous Na2S2O3 or NaHSO3 until colourless, then washing with water, dilute aqueous Na2CO3, and more water, drying with CaCl2 and distilling. It is stored in a brown bottle away from sunlight in contact with a small amount of mercury, powdered silver or copper. (Prolonged exposure of mercury to methyl iodide forms methylmercuric iodide.) Methyl iodide can be dried further using CaSO4 or P2O5. An alternative purification is by percolation through a column of silica gel or activated alumina, then distillation. The solution can be degassed by using a repeated freeze-pump-thaw cycle. [Beilstein 1 IV 87.]
Iodomethane is a useful methylating agent that mediates the alkylation of carbon, oxygen, sulfur, nitrogen and phosphorus nucleophiles[9, 10]. For example, phenol reacts with methyl iodide to give anisole. In the Monsanto process, the in situ formed iodomethane reacts with carbon monoxide in the presence of a rhodium complex to give acetyl iodide, which on hydrolysis yields acetic acid. It reacts with magnesium to form the Grignard reagent, methyl-magnesium iodide used in organic synthesis. It also finds applications as an intermediate in the manufacture of pharmaceuticals and in phase-transfer catalysts.
Methyl iodide can also be used as a kind of pesticide used to control insects, plant parasitic nematodes, soil borne pathogens, and weed seeds in vegetables. It can be used in the field growing strawberries, peppers, nut crops, tomatoes, grape vines, ornamentals and turf and nursery growing strawberries, stone fruits, tree nuts, and conifer trees. Its fumigant action is thought to be via the nucleophilic displacement(SN2) reaction in various amino acids and peptides within target organisms. It can also be used as a fire extinguisher[4, 5, 13, 14].
Methylating agent; in microscopy because of its high refractive index; as imbedding material for examining diatoms; in testing for pyridine. Light sensitive etching agent for electronic circuits; component in fire extinguishers.
Air & Water Reactions
Soluble in water. Sinks and slowly decomposes in water forming poisonous vapor cloud of HI.
Iodomethane can be synthesized by the following several methods:
I. The reaction between methanol with phosphorus triiodide
II. The reaction of dimethyl sulfate with potassium iodide in the presence of calcium carbonate
III. The reaction of methanol with aqueous hydrogen iodide.
IV. The reaction of iodoform with potassium hydroxide and dimethyl sulfate in the presence of ethanol.
.Iodomethane is an approved pesticide used to control insects, plant parasitic nematodes, soil borne pathogens and weed seeds.
A colorless liquid that turns brown on exposure to light. Denser than water. Contact may irritate skin, eyes and mucous membranes. Very toxic by ingestion, inhalation and skin absorption.
Iodomethane, an alkyl halide, is a colorless to pale yellow liquid with an acrid odor. It is stable at room temperature in sealed containers, non-corrosive to metals, and incompatible with strong oxidizing and reducing agents. On exposure to light and moisture, the color turns yellow, red or brown due to decomposition and the liberation of free iodine. When heated to decomposition in air at 270 degree, toxic iodine vapors are emitted. Iodomethane is soluble in water, and is miscible with alcohol and ether[5-7].
Iodomethane is also commonly called methyl iodide. It is a volatile liquid related to methane by replacement of hydrogen. Iodomethane is miscible with common organic solvents. It is colourless, although upon exposure to light, samples develop a purplish tinge. Iodomethane (methyl iodide) is widely used in organic synthesis to deliver a methyl group, via the transformation called methylation.
Iodomethane(also known as methyl iodide), is a kind of alkyl halide. It is naturally emitted by rice plantations in small amounts. Algae are a great natural producer of it with annual output of being greater than 214,000 tons. Therefore, it exists in ocean in large amount. Terrestrial fungi and bacteria also produce certain amount of iodomethane[2, 3]. It is used in organic synthesis as a source of methyl groups.
Methyl iodide had been approved for use as a pesticide by the United States Environmental Protection Agency in 2007 as a pre-plant biocide used to control insects, plant parasitic nematodes, soil borne pathogens, and weed seeds in vegetables such as. It was registered for use as a pre-plant soil treatment for field grown strawberries, peppers, nut crops, tomatoes, grape vines, ornamentals and turf and nursery grown strawberries, stone fruits, tree nuts, and conifer trees. After the discovery phase in a consumer lawsuit, the manufacturer withdrew the fumigant citing its lack of market viability.
Inhalation of vapor causes lung congestion and pulmonary edema. Higher concentrations causes rapid narcosis and death. Contact with liquid irritates eyes and burns skin.
Warning and toxicity
Iodomethane may have certain toxicity when exposure to human and animals[20-22]. In humans, acute[short-term] exposure when inhaling iodomethane may depress the central nervous system(CNS), irritate the lungs and skin, and affect the kidneys. Massive acute inhalation exposure to methyl iodide has led to pulmonary edema. Acute inhalation exposure of humans to methyl iodide has resulted in nausea, vomiting, vertigo, ataxia, slurred speech, drowsiness, skin blistering, and eye irritation[20, 21]. Chronic(long-term) exposure of humans to methyl iodide by inhalation may affect the CNS and cause skin burns in animals and humans. EPA has not classified methyl iodide for potential carcinogenicity[20-22].