ALPHA-HCH

Description

BHC is a white-to-brownish crystalline solid witha musty, phosgene-like odor. Molecular weight = 290.82;Freezing/Melting point = 65℃. Hazard Identification (basedon NFPA-704 M Rating System): Health 2, Flammability 1,Reactivity 0. BCH consists of eight stereoisomers of which thegamma(~) isomer is most insecticidally active and hence mostimportant. See also“Lindane.”

Chemical properties

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

Physical properties

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).

The Uses of ALPHA-HCH

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).

The Uses of ALPHA-HCH

Not produced commercially in the U.S. and its sale is prohibited by the U.S. EPA.

Definition

ChEBI: Beta-hexachlorocyclohexane is the beta-isomer of hexachlorocyclohexane. It has a role as a persistent organic pollutant. It is an organochlorine pesticide and a hexachlorocyclohexane.

General Description

White crystalline powder.

Air & Water Reactions

Insoluble in water.

Reactivity Profile

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.

Health Hazard

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

Fire Hazard

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.

Safety Profile

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.

Potential Exposure

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.

First aid

If this chemical gets into the eyes, remove anycontact lenses at once and irrigate immediately for at least30 min, occasionally lifting upper and lower lids. Seek med-ical ;attention immediately. If this chemical contacts theskin, remove contaminated clothing and wash immediatelywith soap and water. Speed in removing material from skinis of extreme importance. Shampoo hair promptly if con-taminated. Seek medical attention immediately. If thischemical has been inhaled, remove from exposure, beginrescue ;breathing (using universal precautions, includingresuscitation mask) if breathing has stopped and CPR ifheart action has stopped. Transfer promptly to a medicalfacility. When this chemical has been swallowed, get medi-cal attention. Give large quantities of waterand inducevomiting. Do not make an unconscious person vomit.

Environmental Fate

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).

storage

Color Code- Blue: Health Hazard/Poison: Storein a secure poison location. Prior to working with thischemical you should be trained on its proper handling andstorage. Store in tightly closed containers in a cool, well-ventilated area away from alkalis, powdered iron, alumi-num, and zinc. Where possible, automatically pump liquidfrom drums or other storage containers to process contain-ers. A regulated, marked area should be established wherethis chemical is handled, used, or stored in compliance withOSHA Standard 1910.1045.

Shipping

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

Purification Methods

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.]

Incompatibilities

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.

Waste Disposal

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.