Метоксихлор

Описание

Methoxychlor is a structural analogue of DDT but is not as persistent in the environment as DDT.

Химические свойства

Methoxychlor is a colourless or pale yellow, crystalline synthetic organochlorine insecticide with mild fruity odour. It is available in the form of powder or crystals. Methoxychlor is moderately soluble in water and is soluble in a variety of organic solvents.

Физические свойства

White to gray, or pale yellowish-orange crystals or powder. Nonflammable but may be combustible if dissolved in a flammable organic solvent or petroleum distillate for application. Pungent to mild, fruity odor. Odor threshold concentration in water is 4.7 mg/kg (quoted, Keith and Walters, 1992).

Использование

Methoxychlor is effective against flies, mosquitos, cockroaches, and a wide variety of other insects. This insecticide is used on agricultural crops and livestock, and in animal feed, barns, and grain storage bins. Some pesticide products that contain methoxychlor are used for controlling insects in gardens or on pets.

Общее описание

METHOXYCHLOR is a white crystalline solid which is often dissolved in a liquid carrier such as diesel oil. METHOXYCHLOR can cause illness by inhalation, skin absorption and/or ingestion. The primary hazard is the threat to the environment. Immediate steps should be taken to limit its spread to the environment. If dissolved in a liquid carrier, METHOXYCHLOR can easily penetrate the soil and contaminate groundwater and nearby streams. METHOXYCHLOR is used as a pesticide.

Реакции воздуха и воды

Insoluble in water.

Профиль реактивности

METHOXYCHLOR turns pink or tan on exposure to light. METHOXYCHLOR is incompatible with alkaline materials, especially in the presence of catalytically-active metals. METHOXYCHLOR is slightly corrosive to iron and aluminum. METHOXYCHLOR is decomposed by refluxing with sodium in isopropyl alcohol. METHOXYCHLOR is also incompatible with strong oxidizers. METHOXYCHLOR will attack some forms of plastics, rubber and coatings. .

Опасность

Toxic material. Liver damage and central nervous system impairment. Questionable carcinogen.

Угроза здоровью

Low toxicity; acute and chronic effects aremuch less serious than those of the structurally similar DDT; skin absorption low;may cause kidney damage on chronic exposure; oral LD50 value (rats): 6000 mg/kg(ACGIH 1986); no evidence of carcinogenicity to animals or humans; exposure limit:TLV-TWA 10 mg/m³ (ACGIH, MSHA, andOSHA); RCRA Waste Number U247
Methoxychlor is a reproductive toxicant.Exposure of young adult male rats to methoxychlor reduced their serum testosterone levels (Murono et al. 2006). It metabolized in theliver into 2,2-bis(p-hydroxyphenyl)-1,1,1-trichloroethane and both methoxychlor and itsmetabolite were found to exhibit weak estrogenic and antiandrogenic activities. Flynnet al. (2005) have reported that long-termexposure to methoxychlor in diet altered thesexually dimorphic behavior in young ratsof both sexes. The study indicated that consumption of sodium solution increased in ratsfrom such exposure. The toxicity of methoxychlor, particularly in the central nervous system, may be attributed to its inhibition of brainmitochondrial respiration which probably iscaused by an increased production of reactiveoxygen species (Schuh et al. 2005).

Пожароопасность

Special Hazards of Combustion Products: Irritating and toxic hydrogen chloride gas may be formed in fire.

Сельскохозяйственное использование

Insecticide: Not approved for use in EU countries . Not registered for use in the U.S. There are 33 global suppliers . The U.S. EPA lists 826 active and/or canceled products containing methoxychlor. Methoxychlor was introduced as an insecticide in 1945. It is a close relative of DDT and has been increasing in use since the ban on DDT in 1972 because of its very low mammalian toxicity for home and garden, on domestic animals for fly control, for elm bark-beetle vectors of Dutch elm disease, and for blackfly larvae in streams. Methoxychlor is registered for about 87 crops such as alfalfa; nearly all fruits and vegetables, corn, wheat, rice, and other grains; beef and dairy cattle; and swine, goats and sheep, and for agricultural premises and outdoor fogging. It is available in wettable and dust powders, emulsifiable concentrates, granules, and as an aerosol. It is combined in formulations with malathion, parathion, piperonyl butoxide, and pyrethrins.

Торговое название

CHEMFORM®; HIGALMETOX®; MARLATE®; METOX®; MOXIE®; PRENTOX®

Профиль безопасности

Suspected carcinogen with experimental carcinogenic, tumorigenic, and teratogenic data. Moderately toxic by intraperitoneal and skin contact routes. Human systemic effects by skin contact: somnolence. Experimental reproductive effects. Mutation data reported. When heated to decomposition it emits highly toxic fumes of Cl-. See also DDT and CHLOROPHENOLS.

Канцерогенность

Female mice fed up to 2000mg/kg and males given 3500 mg/kg in the diet for 78 weeks showed no statistically significant increase in the incidence of benign and malignant tumors that could be attributed to methoxychlor.10 Chronic feeding studies in rats, at 850 and 1400mg/kg for males and females, respectively, also showed no significant carcinogenic responses, although high tumor rates in controls may have masked detection.10 Based on NCI results and several earlier animal studies, the IARC has determined that there is insufficient evidence that methoxychlor is carcinogenic in experimental animals and that it is not classifiable as to its carcinogenicity to humans.

Метаболический путь

Upon UV irradiation with methyl oleate, methoxychlor is extensively added to the carbon ? carbon double bond of methyl oleate via radical mechanisms. Besides chlorinated stearic acids, several addition products are formed, offering new possibilities to produce bound residues in plants. The incubation of methoxychlor with liver microsomes from untreated and phenobarbital-treated rats and donors, in the presence of NADPH, yields three phenolic metabolites: monodemethylated and didemethylated methoxychlor and its hydroxylated (trihydroxy) methoxychlor. The metabolic route of methoxychlor by monooxygenases involves sequential demethylations to the dihydroxy derivative and a subsequent ring hydroxylation.

Методы очистки

Free the insecticide from 1,1-bis(p-chlorophenyl)-2,2,2-trichloroethane by crystallising from EtOH. It is dimorphic and also crystallises from Et2O/EtOH (m 92o). [Fritsch & Feldmann Justus Liebigs Ann Chem 306 77 1899, Smith et al. Aust J Chem 29 743 1976, Beilstein 6 H 1007.]