ХЛОРОТАЛОНИЛ

Описание

Chlorothalonil is a pesticide fungicide commonly used in the cultivation of ornamental plants and flowers, rice, and onions. In banana plantations it is used in fumigations by airplanes. It can be used as a preservative of paints and of woods. Chlorothalonil can induce contact urticaria, irritant and allergic contact dermatitis, erythema dychromicum perstans or folliculitis mainly in agricultural workers, in those in wood-related professions or in hortieulturists.

Химические свойства

Chlorothalonil is a combustible, white, odorless, crystalline solid

Использование

Chlorothalonil is a polychlorinated aromatic broad spectrum non-systematic fungicide. Chlorothalonil is used heavily in agriculture field on crops such as peanuts, potatoes and tomatoes. Chlorothaloni l is a probable human carcinogen (Group B2) and is highly toxic to fish and aquatic invertabrates.

Определение

ChEBI: A dinitrile that is benzene-1,3-dicarbonitrile substituted by four chloro groups. A non-systemic fungicide first introduced in the 1960s, it is used to control a range of diseases in a wide variety of crops.

Общее описание

Colorless crystals or granules or light gray powder. Melting point 250-251°C. No odor when pure; technical grade has a slightly pungent odor. A fungicide formulated as water-dispersible granules, wettable powder, or dust.

Реакции воздуха и воды

Insoluble in water.

Профиль реактивности

Chlorothalonil is stable in neutral or acidic aqueous media. May react violently with strong oxidizing acids [Farm Chemicals Handbook]. Incompatible with other oxidizing agents such as peroxides and epoxides. Breaks down slowly in basic aqueous media (half-life 38.1 days at pH 9. [Farm Chemicals Handbook].

Угроза здоровью

Chlorothalonil is an irritant to the skin and eyes and has been reported to produce allergic contact dermatitis in exposed workers.

Пожароопасность

Literature sources indicate that Chlorothalonil is nonflammable.

Сельскохозяйственное использование

Fungicide: Chlorothalonil is a broad-spectrum fungicide. It is used on vegetables, peanuts, potatoes, small fruits, trees, turf, roses, ornamentals, and other crops. In California, the top crops are tomatoes, onions, celery, and landscaping. It targets fungal blights, needlecasts, and cankers on conifer trees. This is the second most used fungicide in the U.S. It can be found in formulations with many other pesticides

Торговое название

ATLAS CROPGARD®; BANOL C®; BB CHLOROTHALONIL®; BOMmHgDIER®; BRAVO®; BRAVO® 6 F; BRAVO® 500; BRAVO® 6 F; BRAVO ULTREX®; BRAVO-W-75®; CHILTERN OLE®; CONTACT® 75; DAC® 2787; DACONIL®; DACONIL® 2787 FUNGICIDE; DACONIL® 2787 W; DACONIL® F; DACONIL® M; DACONIL® TURF; DACOSOIL®; DIVA FUNGICIDE®[C]; ECHO®; EXOTHERM®; EXOTHERM TERMIL®; FORTURF®; FUNGINIL®; IMPACT EXCEL®; JUPITAL®; NUOCIDE®; OLE®; PILLARICH®; POWER CHLOROTHALONIL® 50; REPULSE®; RIDOMIL GOLD/BRAVO®; SICLOR®; SIPCAM® UK ROVER 5000; SWEEP®; TER-MIL®; TPN®; TPN (PESTICIDE)®; TRIPART FABER®; TRIPART ULTRAFABER®; TUFFCIDE®

Контактные аллергены

Chlorothalonil is a fungicide widely used in the cultivation of ornamental plants and flowers, rice, and onions. In banana plantations it is used in fumigations by airplanes. It can be used as a preservative of paints and woods. It can induce contact urticaria, irritant and allergic contact dermatitis, erythema dyschromicum perstans, or folliculitis mainly in agricultural workers, wood-related professions, or in horticulturists.

Фармаколо?гия

Mechanism of action of this fungicide may be attributed to inhibition of physiological activities of fungal cell constituents by binding reaction. The reaction was observed in buffer solution to substitute hydroxyethylthio radical(s) of 2-mercaptoethanol for chlorine radical(s) on the benzene ring of the fungicide molecule preferably at 4-position (i.e., also 6-) followed by other positions (5). Similar reactions in fungal cells were observed between the fungicide and glutathione and high molecular weight cell constituents having a sulfhydryl group (5,6). The fungicide inhibits activities of thiol-dependent enzymes such as alcohol dehydrogenase, gyceraldehyde-3-phosphate dehydrogenase, and malate dehydrogenase (5,6). Preliminary addition of glutathione or dithiothreitol protects the thiol enzymes from inhibition but later addition does not reverse the enzyme inhibition. Chymotrypsin, a non-thiol enzyme, was not inhibited by this fungicide. Binding of the fungicide to the sulfhydryl group of cell constituents appears to be the primary mode of its action.

Профиль безопасности

Suspected carcinogen with experimental carcinogenic data. Moderately toxic by skin contact and intraperitoneal routes. Mildly toxic by ingestion. Mutation data reported. When heated to decomposition it emits very toxic fumes of Cl-, NOx, and CN-. See also NITRILES.

Возможный контакт

Chlorothalonil is a broad spectrum fungicide; used as fungicide in coatings; caulk, wood preservative, and antifouling systems. Therefore, people involved in its manufacture, formulation, and application can be exposed.

Канцерогенность

Chlorothalonil was not mutagenic in a variety of assays, nor did it bind to DNA.3 The compound does not appear to have genotoxic potential and probably exerts its carcinogenic action in rodents via a nongenotoxic mechanism. 3 Rodent models may be a poor predictor of carcinogensis in humans because of species differences in metabolic pathways leading to carcinogenesis in the kidney and the lack of a comparable organ (forestomach) in humans.
The IARC has determined that there is sufficient evidence for carcinogenicity of chlorothalonil in experimental animals and inadequate evidence in humans.

Экологическая судьба

Biological. From the first-order biotic and abiotic rate constants of chlorothalonil in estuarine water and sediment/water systems, the estimated biodegradation half-lives were 8.1–10 and 1.8–5 days, respectively (Walker et al., 1988).
Soil. Metabolites identified in soil were 1,3-dicyano-4-hydroxy-2,5,6-trichlorobenzene, 1,3-dicarbamoyl-2,4,5,6-tetrachlorobenzene and 1-carbamoyl-3-cyano-4-hydroxy-2,5,6- trichlorobenzene (Rouchaud et al., 1988). The half-life was reported as 4.
Groundwater. According to the U.S. EPA (1986) chlorothalonil has a high potential to leach to groundwater
Plant. Degrades in plants to 4-hydroxy-2,5,6-trichloroisophthalonitrile (Hartley and Kidd, 1987), 1,3-dicyano-4-hydroxy-2,5,6-trichlorobenzene and 1,3-dicarbamoyl-2,4,5,6- tetrachlorobenzene (Rouchaud et al., 1988). No evidence of degradation products were reported in apple foliage 15 days after application. The half-life of chlorothalonil was 4.1 days (Gilbert, 1976)

Метаболический путь

By in vitro incubation of 14C-chlorothalonil (CTL) with rat stomach, duodenum, and cecum contents, with dog stomach, duodenum, and colon contents, and with human feces and stomach contents, transformation of CTL mostly occurs in rat cecum contents, dog colon contents, and human feces, in which unchanged CTL accounts for 46.7, 29.7, and 22.6% of applied radioactivity, respectively. In those incubations, the identified metabolites are 2,5,6-trichloro-4- methylthioisophthalonitrile, 2,5,6-trichloro-4- thioisophthalonitrile, 3-thia-1-cyano-2,5,6- trichloroisoindolinone, 2,5,6-trichloro-4- hydroxyisophthalonitrile, and 2,5,6- trichloroisophthalonitrile. In rats, CTL is transformed to 4,6-bis(N-acetylcystein-S-yl)-2,5- dichloroisophthalonitrile.
The photolysis of CTL solutions in alcohols (ethanol and methanol separately) with exposure to UV irradiation yields 4,5,7-trichloro-6-cyano-3- methylbenzo-g -lactone and dichlorobenzo-bis-g -lactone derivatives as major degradation products in ethanol. In methanol, 4,5,7-trichloro-6-cyanobenzo-g -lactone is the only photoproduct detected.

Метаболизм

Degradation pathways of chlorothalonil in upland and paddy soils (7) and by soil bacteria (8) were studied, and most initial products were identified to be the results of chlorine substitution reactions, by hydrogen (i.e., dechlorination), by hydroxyl, and by methylthio groups. These reactions took place first at the 4-position of the ring followed by reactions at other positions as in the reaction with thiol compounds. Paddy soil degraded the fungicide faster than did upland soil. Chlorine substitution reaction at 4-position of the fungicide molecule was also reported in benzene solution under sunlight, and the phenyl-substituted product was identified (9). Similar photolysis was observed in other aromatic hydrocarbon solutions but not in acetone, hexane, and ether solutions.

Перевозки

UN3276 Nitriles, liquid, toxic, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name Required, Potential Inhalation Hazard (Special Provision 5). UN2588 Pesticides, solid, toxic, Hazard Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name Required

Несовместимости

Contact with strong oxidizers may cause a fire and explosion hazard. Thermal decomposition may include fumes of hydrogen cyanide. Nitriles may polymerize in the presence of metals and some metal compounds. They are incompatible with acids; mixing nitriles with strong oxidizing acids can lead to extremely violent reactions. Nitriles are generally incompatible with other oxidizing agents such as peroxides and epoxides. The combination of bases and nitriles can produce hydrogen cyanide. Nitriles are hydrolyzed in both aqueous acid and base to give carboxylic acids (or salts of carboxylic acids). These reactions generate heat. Peroxides convert nitriles to amides. Nitriles can react vigorously with reducing agents. Acetonitrile and propionitrile are soluble in water, but nitriles higher than propionitrile have low aqueous solubility. They are also insoluble in aqueous acids.

Утилизация отходов

Incineration in a unit operating @ 850C equipped with off-gas scrubbing equipment.