альфа-1,2,3,4,5,6-гексахлорциклогексан

Химические свойства

BHC is a white-to-brownish crystalline solid with a musty, phosgene-like odor.

Физические свойства

Brownish to white monoclinic prisms, crystalline solid or powder with a phosgene-like odor (technical grade). An odor threshold concentration of 88 μg/kg was reported by Sigworth (1964).

Использование

α-1,2,3,4,5,6-Hexachlorocyclohexane is an organochloride which is one of the isomers of hexachlorocyclohexane and is an byproduct of insecticide Lindane (L465990).

Общее описание

White crystalline powder.

Реакции воздуха и воды

Insoluble in water.

Профиль реактивности

Halogenated aliphatic compounds, such as ALPHA-HCH, are moderately or very reactive. Reactivity generally decreases with increased degree of substitution of halogen for hydrogen atoms. Materials in this group may be incompatible with strong oxidizing and reducing agents. Also, they may be incompatible with many amines, nitrides, azo/diazo compounds, alkali metals, and epoxides.

Угроза здоровью

ACUTE/CHRONIC HAZARDS: Carcinogen. Toxic. Irritant. Hazardous decomposition product.

Пожароопасность

Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes. Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.). Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated.

Профиль безопасности

ConfEmed carcinogen with experimental carcinogenic, tumorigenic, and neoplastigenic data. Poison by ingestion. Mutation data reported. When heated to decomposition it emits toxic fumes of Cl-. See also BENZENE HEXACHLORIDE and other benzenehexachloride entries.

Возможный контакт

The major commercial usage of BHC is based upon its insecticidal properties. α-BCH is used as an Agricultural chemical, pesticide, pharmaceutical, and veterinary drug. The 7-isomer has the highest acute toxic ity, but the other isomers are not without activity. It is gen erally advantageous to purify the 7-isomer from the less active isomers. The γ-isomer acts on the nervous system of insects, principally at the level of the nerve ganglia. As a result, lindane has been used against insects in a wide range of applications including treatment of animals, buildings, humans for ectoparasites, clothes; water for mosquitoes; living plants; seeds and soils. Some applications have been abandoned due to excessive residues, e.g., stored food stuffs. By voluntary action, the principal domestic producer of technical grade BHC requested cancellation of its BHC registrations on September 1, 1976. As of July 21, 1978, all registrants of pesticide products containing BHC voluntar ily canceled their registrations or switched their former BHC products to lindane formulations.

Экологическая судьба

Biological. Clostridium sphenoides degraded α-BHC to δ-3,4,5,6-tetrachloro-1-cyclo hexane (Heritage and MacRae, 1977a). In four successive 7-day incubation periods, α- BHC (5 and 10 mg/L) was recalcitrant to degradation in a settled domestic wastewater inoculum (Tabak et al., 1981).
Soil. Under aerobic conditions, indigenous microbes in contaminated soil produced pentachlorocyclohexane. However, under methanogenic conditions, α-BHC was converted to chlorobenzene, 3,5-dichlorophenol and the tentatively identified compound 2,4
Photolytic. When an aqueous solution containing α-BHC was photooxidized by UV light at 90–95°C, 25, 50 and 75% degraded to carbon dioxide after 4.2, 24.2 and 40.0 hours, respectively (Knoevenagel and Himmelreich, 1976). In basic, aqueous solution
Chemical/Physical. Emits very toxic chloride fumes when heated to decomposition (Lewis, 1990). α-BHC will hydrolyze via trans-dehydrochlorination of the axial chlorines resulting in the formation of hydrochloric acid and the intermediate 1,3,4,5,6-pentachlo rocyclo-hexene. The intermediate will undergo further hydrolysis resulting in the formation of 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene and hydrochloric acid (Kollig, 1993).

Перевозки

UN2761 Organochlorine pesticides, solid, toxic, Hazard Class: 6.1; Labels: 6.1-Poisonous materials.

Методы очистки

Crystallise it from EtOH. Purify it also by zone melting. Possible CANCER AGENT, TOXIC. [: Beilstein 1 H 23, : Beilstein 5 I 8, many isomers : Beilstein 5 III 41, 5 IV 55.]

Несовместимости

Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explo sions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides. Decomposes on contact with powdered iron, aluminum, zinc, and on contact with strong bases producing trichlorobenzene.

Утилизация отходов

A process has been developed for the destructive pyrolysis of benzene hexachloride @ 400 500℃ with a catalyst mixture which contains 5 10% of either cupric chloride, ferric chloride; zinc chloride; or aluminum chloride on activated carbon.