МЕТИЛ йодистый

Химические свойства

light yellow to light pink liquid

Физические свойства

Clear, colorless liquid which may become yellow, red, or brown on exposure to light and moisture

Использование

.Iodomethane is an approved pesticide used to control insects, plant parasitic nematodes, soil borne pathogens and weed seeds.

Методы производства

Methyl iodide has had very limited use as a chemical intermediate (methylations), and in microscopy because of its high refractive index, as imbedding materials for examining diatoms, and in tests for pyridine. It has been proposed as a fire extinguisher and insecticidal fumigant. It is a product of natural biological processes. Methyl iodide is a currently registered pesticide.

Определение

ChEBI: A member of the class of iodomethanes that is methane in which one of the hydrogens is replaced by iodine.

Общее описание

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.

Реакции воздуха и воды

Soluble in water. Sinks and slowly decomposes in water forming poisonous vapor cloud of HI.

Профиль реактивности

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.

Опасность

Toxic by ingestion, inhalation, and skinabsorption; narcotic, irritant to skin. Eye damageand central nervous system impairment. Question-able carcinogen.

Угроза здоровью

Inhalation of vapor causes lung congestion and pulmonary edema. Higher concentrations causes rapid narcosis and death. Contact with liquid irritates eyes and burns skin.

Пожароопасность

Noncombustible. High vapor pressure may cause containers to burst at elevated temperatures.

Воспламеняемость и взрывоопасность

Noncombustible. High vapor pressure may cause containers to burst at elevated temperatures.

Профиль безопасности

Confirmed carcinogen with experimental neoplastigenic and tumorigenic data. A poison by ingestion, intraperitoneal, and subcutaneous routes. Moderately toxic by inhalation and skin contact. A human skin irritant. Human mutation data reported. A strong narcotic and anesthetic. Explosive reaction with trialkylphosphines, silver chlorite. Violent reaction with oxygen (at 3000C), sodium. When heated to decomposition it emits toxic fumes of I-.

Возможный контакт

Methyl iodide is used in fire extinguishers; as an intermediate in the manufacture of pharmaceuticals and some pesticides.

Канцерогенность

Druckrey et al. reported local sarcomas following weekly subcutaneous injection in BD strain rats. Strain A mice (a susceptible strain) that were injected with methyl iodide were reported to have a slight but significant increase in the number of lung tumors per mouse. Poirer et al. administered iodomethane dissolved in tricaprylin to male and female strain A mice (10/sex/dose) three times weekly by intraperitoneal injection. There was a marginally statistically significant trend for increased lung tumors in treated mice but the outcome was considered equivocal: no clear dose–response relationship and occurrence of spontaneous tumors in untreated mice.
Under the 2005 Guidelines for Carcinogen Risk Assessment (121), the lack of available evidence suggests that there is “inadequate information to assess the carcinogenic potential for iodomethane.”
An early evaluation by the IARC classified iodomethane as carcinogenic in rats. Two subsequent evaluations (123, 124) determined that there is limited evidence for carcinogenicity in experimental animals and the compound is not classifiable regarding carcinogenicity to humans. ACGIH has also reviewed iodomethane carcinogenicity and classified it as category A2, suspected human carcinogen; however, the A2 classification was withdrawn in 1996. Iodomethane was delisted as a carcinogen in the NTP 5th Annual Report on Carcinogens on the basis of the 1986 IARC reevaluation. NTP has not tested iodomethane for carcinogenicity. The State of California determined under Proposition 65 that methyl iodide is a carcinogen, based on the 1977 IARC evaluation. Neither a Toxicological Profile nor an Environmental Health Criteria Monograph has been published.

Экологическая судьба

Chemical/Physical. Anticipated products from the reaction of methyl iodide with ozone or OH radicals in the atmosphere are formaldehyde, iodoformaldehyde, carbon monoxide, and iodine radicals (Cupitt, 1980). With OH radicals, CH2, methyl radical, HOI and water are possible reaction products (Brown et al., 1990). The estimated half-life of methyl iodide in the atmosphere, based on a measured rate constant for the vapor phase reaction with OH radicals, ranges from 535 h to 32 wk (Garraway and Donovan, 1979).
Hydrolyzes in water forming methyl alcohol and hydriodic acid. The estimated half-life in water at 25 °C and pH 7 is 110 d (Mabey and Mill, 1978). At 70 °C, the hydrolysis rate was determined to be 3.2 x 10^-5/sec which is equivalent to a half-life of 6 h. (Glows and Wren, 2003). May react with chlorides in seawater to form methyl chloride (Zafiriou, 1975).

Перевозки

UN2644 Methyl iodide, Hazard Class: 6.1; Labels: 6.1-Poison Inhalation Hazard, Inhalation Hazard Zone B

Методы очистки

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.]

Несовместимости

May form explosive mixture with air. Slowly reacts with water forming poisonous hydrogen iodide. Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides. Violent reaction with strong oxidizers, strong reducing agents, strong bases; trialkylphosphines, silver chlorite; calcium, oxygen, sodium. Decomposes @ 270C. Halogenated aliphatic compounds are moderately or very reactive. Halogenated organics generally become less reactive as more of their hydrogen atoms are replaced with halogen 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

Утилизация отходов

Consult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste containing this contaminant (≥100 kg/mo) must conform to EPA regulations governing storage, transportation, treatment, and waste disposal