Hexachlorocyclohexane

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Hexachlorocyclohexane , more precisely 1,2,3,4,5,6-hexachlorocyclohexane , is the name of a mixture of different stereoisomeric chemical compounds from the group of halogenated hydrocarbons .

overview

The most common compound is γ-hexachlorocyclohexane , which is used as an insecticide and is better known under the name lindane. The other isomeric chemical compounds are α-hexachlorocyclohexane, β-hexachlorocyclohexane and δ-hexachlorocyclohexane. There is also ε-hexachlorocyclohexane in small quantities. The η, θ and ζ isomers were only synthesized in the laboratory. Because the earlier through the manufacturing process (from benzene , which is chlorinated under UV radiation , whereby five of the eight possible isomers are formed) with existing and with released α-, β-, δ- and ε-isomers are more toxic than Insecticide proved to be less effective and even more difficult to break down than the problematic γ-structure (which is contained in technical hexachlorocyclohexane only 9-18%), later only isomerically pure γ-hexachlorocyclohexane was used as a food and contact poison. Lindane (i.e. γ-hexachlorocyclohexane) was first produced in 1825 by Michael Faraday . During thermal decomposition, phosgene and hydrogen chloride , among other things, are formed . α-Hexachlorocyclohexane is the only 1,2,3,4,5,6-hexachlorocyclohexane to be found in two enantiomeric forms: (+) - α-hexachlorocyclohexane and (-) - α-hexachlorocyclohexane. In the insecticide, α-hexachlorocyclohexane is found as a racemate [1: 1 mixture of (+) - α-HCH and (-) - α-HCH] for production reasons. However, mainly (-) - α-HCH was found in the liver of wild deer, and the rate of degradation of (+) - α-HCH is significantly higher than that of (-) - α-HCH. The degradation takes place enantioselectively.

properties

1,2,3,4,5,6-hexachlorocyclohexanes
Surname (-) - α- Hexachlorocyclohexane (+) - α-Hexachlorocyclohexane β- hexachlorocyclohexane γ- hexachlorocyclohexane ( lindane ) δ- hexachlorocyclohexane ε -hexachlorocyclohexane ζ -hexachlorocyclohexane η -hexachlorocyclohexane θ -hexachlorocyclohexane
Structural formula (+) - α-HCH (-) - α-HCH β-HCH γ-HCH δ-HCH ε-HCH ζ-HCH η-HCH θ-HCH
spatial structure
(for alpha
with hydrogen atoms)
Alpha-hexachlorocyclohexane with H.svg (+) - Alpha-Hexachlorocyclohexane.svg Beta-Hexachlorocyclohexane.svg Gamma-Hexachlorocyclohexane.svg Delta-Hexachlorocyclohexane.svg Epsilon-Hexachlorocyclohexane.svg ζ-HCH η-HCH θ-HCH
CAS number 608-73-1 (mixture of isomers)
319-84-6 (racemate) 319-85-7 58-89-9 319-86-8 6108-10-7 6108-11-8 6108-12-9 6108-13-0
119911-70-5 119911-69-2
PubChem 727
Molecular formula C 6 H 6 Cl 6
Molar mass 290.83 g mol −1
Physical state firmly
Brief description colorless to yellowish crystalline solid
Melting point 158 ° C 309 ° C 113 ° C 139 ° C 219 ° C
boiling point 288 ° C 323 ° C (decomposition)
density 1.89 g cm −3 1.85 g cm −3 1.55 g cm −3
solubility very sparingly soluble in water (0.2–8 mg / l)
GHS pictograms
06 - Toxic or very toxic 08 - Dangerous to health 09 - Dangerous for the environment

danger
H and P phrases H: 301-312-351-410
EUH: no EUH phrases
P: 273-280-301 + 310-501
MAK Switzerland: 1 mg m −3 (measured as inhalable dust ) Switzerland: 0.2 mg m −3 (measured as inhalable dust )

Web links

Individual evidence

  1. State Institute for Environmental Protection Baden-Württemberg : Substance report hexachlorocyclohexane (HCH). 1st edition, 1993 ( pdf, 7.37 MB ).
  2. ^ Residues of pesticides in the soil (PDF; 978 kB).
  3. Bernd Pfaffenberger, Ingo Hardt, Heinrich Hühnerfuss, Wilfried A. König , Gerhard Rimkus, Alexandra Glausch, Volker Schurig and Jürgen Hahn: Enantioselective degradation of α-hexachlorcyclohexane and cyclodiene insecticides in roe-deer liver from different regions in Germany , Chemosphere 29 ( 1994) 1543-1554.
  4. a b Entry on alpha-1,2,3,4,5,6-hexachlorocyclohexane in the GESTIS substance database of the IFA , accessed on February 22, 2017(JavaScript required) .
  5. a b c Entry on beta-1,2,3,4,5,6-hexachlorocyclohexane in the GESTIS substance database of the IFA , accessed on February 22, 2017(JavaScript required) .
  6. a b c d Entry on lindane in the GESTIS substance database of the IFA , accessed on February 22, 2017(JavaScript required) .
  7. a b c Entry on delta-1,2,3,4,5,6-hexachlorocyclohexane in the GESTIS substance database of the IFA , accessed on February 22, 2017(JavaScript required) .
  8. CR Ganellin, David J. Triggle; Dictionary of pharmacological agents, ISBN 978-0412466304 .
  9. Data sheet BHC (mixture of hexachlorocyclohexanes) from Sigma-Aldrich , accessed on April 3, 2011 ( PDF ).
  10. Swiss Accident Insurance Fund (Suva): Limits - Current MAK and BAT values (search for 319-84-6 or α-hexachlorocyclohexane ), accessed on March 4, 2020.
  11. Swiss Accident Insurance Fund (Suva): Limit values ​​- current MAK and BAT values (search for 319-85-7 or β-hexachlorocyclohexane ), accessed on March 4, 2020.