Гептахло́р: Свойства, Метаболизм и Токсичность

chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 443853375
| Name = Heptachlor
| ImageFile1 = (+) Heptachlor. svg
| ImageSize1 =
| ImageName1 = Heptachlor
| ImageFile2 = Heptachlor 3D balls. png
| ImageSize2 =
| ImageName2 = Ball and stick model
| PIN = 1,4,5,6,7,8,8 Heptachloro 3a,4,7,7a tetrahydro 1H 4,7 methanoindene
|Section1=
|Section2=Chembox Properties
| Formula = C10H5Cl7
| MolarMass = 373.32 g/mol
| Density = 1.58 g/cm3
| Appearance = White to tan solid
| Odor = Camphorous
| MeltingPtC = 95 to 96
| MeltingPt notes =
| BoilingPtC = 135 to 145
| BoilingPt notes = at 1 1.5 mmHg
| Solubility = 0.0006% (20°C)
| IDLH = Ca [35 mg/m3]
| FlashPt notes = noncombustible

Analogous to the synthesis of other cyclodienes, heptachlor is produced via the Diels Alder reaction of hexachlorocyclopentadiene and cyclopentadiene. The resulting adduct is chlorinated followed by treatment with hydrogen chloride in nitromethane in the presence of aluminum trichloride or with iodine monochloride.

Soil microorganisms transform heptachlor by epoxidation, hydrolysis, and reduction. When the compound was incubated with a mixed culture of organisms, chlordene (hexachlorocyclopentadine, its precursor) formed, which was further metabolized to chlordene epoxide. Other metabolites include 1 hydroxychlordene, 1 hydroxy 2,3 epoxychlordene, and heptachlor epoxide. Soil microorganisms hydrolyze heptachlor to give ketochlordene. Rats metabolize heptachlor to the epoxide 1 exo 1 hydroxyheptachlor epoxide and 1,2 dihydrooxydihydrochlordene. When heptachlor epoxide was incubated with microsomal preparations form liver of pigs and from houseflies, the products found were diol and 1 hydroxy 2,3 epoxychlordene.

Heptachlor is a persistent organic pollutant (POP). It has a half life of ~1.3 4.2 days (air), ~0.03 0.11 years (water), and ~0.11 0.34 years (soil). One study described its half life to be 2 years and claimed that its residues could be found in soil 14 years after its initial application. Like other POPs, heptachlor is lipophilic and poorly soluble in water (0.056 mg/L at 25 °C), thus it tends to accumulate in the body fat of humans and animals. Heptachlor epoxide is more likely to be found in the environment than its parent compound. The epoxide also dissolves more easily in water than its parent compound and is more persistent. Heptachlor and its epoxide absorb to soil particles and evaporate.

The range of oral rat values are 40 mg/kg to 162 mg/kg. Daily oral doses of heptachlor at 50 and 100 mg/kg were found to be lethal to rats after 10 days. For heptachlor epoxide, the oral LD50 values ranging from 46.5 to 60 mg/kg. With rat oral of LD5047mg/kg, heptachlor epoxide is more toxic. A product of hydrogenation of heptachlor, β dihydroheptachlor, has high insecticidal activity and low mammalian toxicity, rat oral LD50>5,000mg/kg.