Гексахлорэтан

Химические свойства

Hexachloroethane is a white solid with a camphor-like odor. It gradually evaporates when it is exposed to air.

Физические свойства

Rhombic, triclinic or cubic, colorless crystals with a camphor-like odor. Odor threshold concentration is 0.15 ppm (quoted, Amoore and Hautala, 1983).

Использование

Hexachloroethane is used as a solvent, infireworks and smoke devices; in explosives,in celluloid, as an insecticide, and as a rubbervulcanizing accelerator. Earlier it was used asan anthelmintic for livestock. Hexachloroethane is a highly efficient chlorinating agent in the preparation of chlorosilanes from hydrosilanes.

Определение

ChEBI: A member of the class of chloroethanes that is ethane in which all the hydrogens are replaced by chloro groups.

Общее описание

Hexachloroethane is a colorless, crystalline solid with a camphor-like odor. Hexachloroethane may cause illness from inhalation or ingestion and may irritate skin, eyes and mucous membranes. When heated to high temperatures Hexachloroethane may emit toxic fumes. The primary hazard is the threat to the environment. Immediate steps should be taken to limit its spread to the environment. Hexachloroethane is used to make other chemicals.

Реакции воздуха и воды

Insoluble in water.

Профиль реактивности

Hexachloroethane can react with hot iron, zinc and aluminum. Dehalogenation of Hexachloroethane by reaction with alkalis and metals will produce unstable chloroacetylenes. Hexachloroethane can also react with strong oxidizing agents. .

Опасность

Toxic by ingestion and inhalation, strong irritant, absorbed by skin. Possible carcinogen.

Угроза здоровью

Vapors of hexachloroethane are an irritant tothe eyes and mucous membranes. Oral dosesof 1000 mg/kg produced weakness, stagger ing gait, and twitching muscles in dogs.Rabbits fed 1000 mg/kg for 12 days devel oped necrosis; a lower amount, 320 mg/kg,caused liver degeneration; no effects wereobserved at a dose level of 100 mg/kg(Weeks 1979).
Acute inhalation toxicity is of a loworder in animals. Subacute toxic effectsin dogs exposed to 260-ppm vapors ofhexachloroethane for 6 hours per day, 5days a week for 6 weeks were tremors,ataxia, hypersalivation, head bobbling, andfacial muscular fasciculations (Weeks 1979).The lethal concentration in rats is 5900 ppmfrom an 8-hour exposure.
LD50 value, oral (rats): 4460 mg/kg
Tests for mutagenicity and teratogenic ity were negative. The carcinogenic poten tial of hexachloroethane was noted in testanimals only at extremely heavy dosagesgiven continuously for a long period of time(ACGIH 1986). It caused liver tumors inmice.

Пожароопасность

Special Hazards of Combustion Products: Irritating hydrogen chloride vapor may form in fire.

Возможный контакт

In the US, about half the HCE is used by the military for smoke-producing devices. It is also used to remove air bubbles in melted aluminum. It may be present as an ingredient in some fungicides, insecticides, lubricants, and plastics. It is no longer made in the United States, but it is formed as a by-product in the production of some chemicals. Can be formed by incinerators when mate rials containing chlorinated hydrocarbons are burned. Some HCE can also be formed when chlorine reacts with carbon compounds in drinking water. As a medicinal, HCE is used as an anthelmintic to treat fascioliasis in sheep and cattle. It is also added to the feed of ruminants, preventing metha nogenesis and increasing feed efficiency. HCE is used in metal and alloy production, mainly in refining aluminum alloys. It is also used for removing impurities from molten metals, recovering metals from ores or smelting products and improving the quality of various metals and alloys. HCE is contained in pyrotechnics. It inhibits the explosive ness of methane and the combustion of ammonium perchlo rate. Smoke containing HCE is used to extinguish fires. HCE has various applications as a polymer additive. It has flameproofing qualities, increases sensitivity to radiation crosslinking, and is used as a vulcanizing agent. Added to polymer fibers, HCE acts as a swelling agent and increases affinity for dyes.

Канцерогенность

Hexachloroethane is reasonably anticipated to be ogen based on sufficient evidence of carcinogenicit a human carciny from studies in experimental animals.

Экологическая судьба

Biological. Under aerobic conditions or in experimental systems containing mixed cultures, hexachloroethane was reported to degrade to tetrachloroethane (Vogel et al., 1987). In an uninhibited anoxic-sediment water suspension, hexachloroethane degraded to tetrachloroethylene. The reported half-life for this transformation was 19.7 min (Jafvert and Wolfe, 1987). When hexachloroethane (5 and 10 mg/L) was statically incubated in the dark at 25 °C with yeast extract and settled domestic wastewater inoculum for 7 d, 100% biodegradation with rapid adaptation was observed (Tabak et al., 1981).
Photolytic. When an aqueous solution containing hexachloroethane was photooxidized by UV light at 90–95 °C, 25, 50, and 75% degraded to carbon dioxide after 25.2, 93.7, and 172.0 h, respectively (Knoevenagel and Himmelreich, 1976).
Chemical/Physical. The reported hydrolysis half-life at 25 °C and pH 7 is 1.8 x 10⁹ yr (Jeffers et al., 1989). No hydrolysis was observed after 13 d at 85 °C and pH values of 3, 7, and 11 (Ellington et al., 1987). Similarly, no measureable hydrolysis was observed under neutral and alkaline conditions (Jeffers and Wolfe, 1996).

Перевозки

UN2811 Toxic solids, organic, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name Required. UN3077 Environmentally hazardous substances, solid, n.o.s., Hazard class: 9; Labels: 9-Miscellaneous hazardous material, Technical Name Required.

Методы очистки

Steam distil it, then crystallise it from 95% EtOH. Dry it in the dark under vacuum. [Beilstein 1 IV 148.]

Несовместимости

Incompatible with strong acids, oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from strong bases.

Утилизация отходов

Incineration after mixing with another combustible fuel. Care must be exercised to assure complete combustion to prevent the formation of phosgene. An acid scrubber is necessary to remove the halo acids pro duced. Consult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste containing this contaminant (≥100 kg/mo) must con form to EPA regulations governing storage, transportation, treatment, and waste disposal.