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| | Hexachlorocyclopentadiene Basic information |
| | Hexachlorocyclopentadiene Chemical Properties |
| Melting point | −10 °C(lit.) | | Boiling point | 239 °C753 mm Hg(lit.) | | density | 1.702 g/mL at 25 °C(lit.) | | vapor pressure | 0.13 psi ( 20 °C) | | refractive index | n20/D 1.5644(lit.) | | Fp | 109 °C | | storage temp. | 2-8°C | | solubility | Chloroform (Sparingly), Ethyl Acetate (Slightly) | | form | Yellow to amber-colored
liquid | | color | Colourless to Pale Yellow | | Water Solubility | 805ug/L(22.5 ºC) | | Henry's Law Constant | 1.64(x 10-2 atm?m3/mol) at 25 °C (gas stripping-GC, Warner et al., 1987)
1.6(x 10-2 atm?m3/mol) (Pankow and Rosen, 1988) | | Exposure limits | NIOSH REL: 10 ppb (100 mg/m3); ACGIH TLV: TWA 0.01 ppm (adopted),
0.002 mg/m3 ppm (skin). | | Stability: | Stability Stable, but light-sensitive. Non-flammable. Very reactive with alkenes and polynuclear hydrocarbons. Explosive with sodium. Incompatible with strong oxidizing agents, most common metals. | | CAS DataBase Reference | 77-47-4(CAS DataBase Reference) | | NIST Chemistry Reference | 1,3-Cyclopentadiene, 1,2,3,4,5,5-hexachloro-(77-47-4) | | EPA Substance Registry System | Hexachlorocyclopentadiene (77-47-4) |
| | Hexachlorocyclopentadiene Usage And Synthesis |
| Description | Hexachlorocyclopentadiene is a pale-yellow/lemon-yellow liquid with a characteristic
musty or pungent odour (odour threshold – 0.03 ppm). Hexachlorocyclopentadiene
does not occur naturally but is a manufactured chemical. It easily evaporates into the air.
Hexachlorocyclopentadiene is the key intermediate in the manufacture of some pesticides,
including heptachlor, chlordane, aldrin, dieldrin, and endrin. Hexachlorocyclopentadiene
is also used in the manufacture of flame retardants and some resins, shock-proof plastics,
fluorocarbons, and dyes. Hexachlorocyclopentadiene quickly breaks down by sunlight
and reacts with other chemicals in the air. | | Chemical Properties | Hexachlorocyclopentadiene is a pale-yellow to amber-colored, oily liquid. Pungent, unpleasant odor. The odor threshold is 0.15 0.33 ppm. Insoluble in water, soluble in ether, carbon tetrachloride and other organic solvents. | | Uses | Hexachlorocyclopentadiene is an organochlorine compound that is used to manufacturing organochlorine insecticides and acaricides, such as mirex, aldrin, dieldrin, chlordane, endosulfan, etc. It is also used to make flame retardants, resins that won't burn, shock-proof plastics, esters, ketones, fluorocarbons, and dyes. | | Preparation | Hexachlorocyclopentadiene is obtained by chlorination of cyclopentadiene in two steps. In addition, using petroleum pentane as raw material, hexachlorocyclopentadiene is synthesized by photochlorination and high temperature chlorination, and the yield is about 70%. | | Application | Hexachlorocyclopentadiene(Hex) is an Intermediate in the manufacture of chlorinated pesticides and flame retardants. The principal end use for Hex is as a key intermediate in the production of chlorinated cyclodiene pesticides, including aldrin, dieldrin, endrin, chlordane, heptachlor, kepone, endosulfan, pentac, isodrin, and mirex. It is also used as an intermediate in the manufacture of flame retardants such as Dechlorane Plus and chlorendic anhydride and, to a lesser extent, in the manufacture of nonflammable resins, polyester resins, pharmaceuticals, unbreakable plastics, acids, esters, ketones, fluorocarbons, and dyes. | | General Description | A pale yellow liquid with a pungent odor. Density 14.3 lb /gal. Solidifies at 50°F. Insoluble in water. Noncombustible. Very toxic by skin absorption and inhalation. Corrosive to tissue. | | Air & Water Reactions | Insoluble in water. Reacts slowly with water to form hydrochloric acid. | | Reactivity Profile | Hexachlorocyclopentadiene is incompatible with strong oxidizing and reducing agents. Also incompatible with many amines, nitrides, azo/diazo compounds, alkali metals (sodium), and epoxides. | | Health Hazard | Hexachlorocyclopentadiene is very toxic and may be fatal if inhaled, swallowed, or absorbed through the skin. The probable human lethal dose is 50-500 mg/kg, or between 1 teaspoon and 1 ounce for a 150 lb. (70 kg) person. Severe exposure induces pulmonary hyperemia and edema, degenerative and necrotic changes in brain, heart and adrenal glands and necrosis of liver and kidney tubules. Questionable carcinogen. | | Fire Hazard | Toxic hydrogen chloride, chlorine, and phosgene gases may form in fires. In presence of moisture, will corrode iron and other materials; flammable and explosive hydrogen gas may collect in enclosed space. Will corrode iron and other metals in the presence of moisture. Reacts slowly with water to form hydrochloric acid; however, the reaction is not hazardous. Hazardous polymerization may not occur. | | Safety | Hexachlorocyclopentadiene is a manufactured chemical that does not occur naturally. Hex has no end uses of its own, and is very toxic following acute (short-term) oral and inhalation exposures. It easily evaporates into the air; the vapor looks like a blue haze. Most of the Hexachlorocyclopentadiene in the environment results from its release during production and disposal. Animal tests suggest that very high levels can cause death. Human data are limited, but it can cause headaches and irritate the nose, throat, eye, and skin. | | Potential Exposure | Hexachlorocyclopentadiene is used to
produce the flame retardant chlorendic anhydride, which
has applications in polyesters; and to produce chlorendic
anhydride and chlorendic acid; which is used as a flame
retardant in resins. Hexachlorocyclopentadiene is also used
as an intermediate in the production of pesticides, such as
aldrin, dieldrin, and endosulfan. | | Environmental fate | Biological. When hexachlorocyclopentadiene (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). In a model ecosystem
containing plankton, Daphnia magna, mosquito larva (Culex pipiens quinquefasciatus), fish
(Cambusia affinis), alga (Oedogonium cardiacum), and snail (Physa sp.), hexachlorocyclopentadiene
degraded slightly, but no products were identified (Lu et al., 1975).
Photolytic. The major photolysis and hydrolysis products identified in distilled water were
pentachlorocyclopentenone and hexachlorocyclopentenone. In mineralized water, the products
identified include cis- and trans-pentachlorobutadiene, tetrachlorobutenyne, and pentachloropentadienoic
acid (Chou and Griffin, 1983). In a similar experiment, irradiation of hexachlorocyclopentadiene
in water by mercury-vapor lamps resulted in the formation of 2,3,4,4,5-
pentachloro-2-cyclopentenone. This compound hydrolyzed partially to hexachloroindenone (Butz
et al., 1982). Other photodegradation products identified include hexachloro-2-cyclopentenone and
hexachloro-3-cyclopentenone as major products. Secondary photodegradation products reported
include pentachloro-cis-2,4-pentadienoic acid, Z- and E-pentachlorobutadiene, and tetrachlorobutyne
(Chou et al., 1987). In natural surface waters, direct photolysis of hexachlorobutadiene via
sunlight results in a half-life of 10.7 min (Wolfe et al., 1982).
Chemical/Physical. Slowly reacts with water forming HCl and 1,1-dihydroxytetrachlorocyclopentadiene
(Kollig, 1993; NIOSH, 1997). The diene is unstable forming polymers (Kollig, 1993). | | Solubility in organics | Based on structurally similar compounds, hexachlorocyclopentadiene is expected to be soluble in
benzene, ethanol, chloroform, methylene chloride, trichloroethylene, and other liquid halogenated
solvents. | | Shipping | UN2646 Hexachlorocyclopentadiene, Hazard
Class: 6.1; Labels: 6.1-Poison Inhalation Hazard, Inhalation
Hazard Zone B. | | Purification Methods | Dry the diene with MgSO4, filter, and distil it under vacuum in a nitrogen atmosphere. Irritates skin and eyes, HIGHLY TOXIC. [McBee et al. J Am Chem Soc 77 4378 1955, UV spectra: Idol et al. J Org Chem 20 1746 1955, Beilstein 5 III 308, 5 IV 381.] | | Toxicity evaluation | Hex’s mechanism of toxicity is incompletely understood.
Because of its characteristics as a chlorinated hydrocarbon, it
would be expected to induce drug-metabolizing enzymes in the
liver. | | Incompatibilities | Reacts slowly with water to form hydro chloric acid; will corrode iron and most metals in presence
of moisture. Explosive hydrogen gas may collect in
enclosed spaces in the presence of moisture. Contact with
sodium may be explosive. | | Waste Disposal | 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. |
| | Hexachlorocyclopentadiene Preparation Products And Raw materials |
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