Lindane

• γ -hexachlorocyclohexane
• Gammahexan
• Gammexane

P03AB02

Colorless and odorless solid

Fixed

1.85 g · cm -3

112.9 ° C

323 ° C ( decomposition)

5.1 Pa ( 20 ° C)

• Practically insoluble in water ( 8.2 mg · l-1 at 25 ° C)
• Well in petroleum ether, soluble in acetone and aromatic chlorinated hydrocarbons

Risk

0.1 mg · m-3

• 76-125 mg · kg -1 ( LD50, rat, oral)
• 44 mg · kg -1 ( LD50, mouse, oral)

Template: Infobox chemical / molecular formula search available

Lindane or γ -hexachlorocyclohexane is a halogenated hydrocarbon, which is used mainly as an insecticide.

Historical Information

Lindane was first produced in 1825 by Michael Faraday. It is named after the Dutch chemist Teunis van der Linden (1884-1965), who had 1912, the γ -hexachlorocyclohexane first isolated and described. The insecticidal action of hexachlorocyclohexane was discovered in 1935, apparently indicated parallel with the British Imperial Chemical Industries and by the French chemist André Dupire, some will also Marc Raucourt from the Agricultural Research Center in Versailles as a co-discoverer. Since 1942, lindane is used as an insecticide. Was used from 1946 to a hexachlorocyclohexane (HCH) isomers in Switzerland. It soon turned out that beets, potatoes and cabbage got a musty flavor through the use of HCH, which made it inedible. As flavor deterioration does not originated from γ - HCH, HCH, but other isomers, methods have been developed to isolate pure lindane. 1950 could be taken up in Switzerland, the production of lindane. The then competent federal research stations covered 1952, the authorizations for plant protection products on HCH - base back. After peaking around 1969 the production of lindane declined worldwide. In Germany lindane may be used as stomach and contact poison since 1980, only in the form of isomerically pure gamma -hexachlorocyclohexane. The earlier yielded alpha-and beta - isomers ( CAS: 319-84-6, 319-85-7 ) were found to be toxic and even harder than degradable which is also not unproblematic gamma structure. Lindane is no longer produced since 1984 in Germany, and since 1989 in East Germany, but is still used in other countries.

Synthesis

Hexachlorocyclohexane is produced by additive chlorination of benzene. An excess of chlorine dissolved in benzene and irradiated with high-energy ultraviolet light. The reaction product is a mixture of various isomers of which alone gamma -hexachlorocyclohexane having insecticidal properties. The proportion of this isomer is only 15 %. To isolate the isomeric mixture is extracted with methanol, whereupon in particular γ -hexachlorocyclohexane goes into solution. Via multiple crystallization processes purity is finally obtained of 99.5%. The undesired isomers are converted into a pyrolytic process to trichlorobenzene since the beginning of the 1970s.

β - hexachloro- cyclohexane

Responsiveness

On heating to lindane decomposed into a toxic, corrosive vapor mixture of hydrogen chloride and phosgene. Contact with metal powders ( aluminum, iron, zinc) to lindane decomposed to form trichlorobenzene.

Use

Lindane was once used as an insecticide in agriculture and forestry, for example, to combat grubs and pests on oilseed rape and cabbage. Another important field of application were the wood preservatives, such as lindane and PCP were included in the wood preservatives Xylamon BV and Xyladecor. In addition, it is used in about one percent dilution in medicine as an external medicine for skin parasites, scabies and mainly in Pedikulosen. According to EU Regulation 850/2004, lindane was allowed to be used only until the end of 2007 in Europe as an insecticide.

Hazard potential

Lindane is prone to strong adsorption, eg algae, and is toxic to aquatic organisms. Since it will degrade slowly and is relatively highly lipophilic, it accumulates strongly in the human food chain especially via fish on. Lindane may therefore not bound under no circumstances get into the environment. The substance is moreover suspected of being carcinogenic. Together with other insecticides based on chlorinated hydrocarbons is discussed as lindane the triggers of Parkinson's disease. In the former GDR, for example, large parts of the trough and Elbeauen are heavily loaded in the Bitterfeld / Dessau with lindane residues.

Lindane also suspected to cause severe disease in excess of the normal figures: Change the internal organs, blood formation, multiple sclerosis, nerve damage. Affects not only farmers, craftsmen and chemical workers but also residents who are the lindane used as a wood preservative exposed via inhalation. A judgment of the Higher Regional Court of Nuremberg According provides Lindane is a non-negligible risk to health when the lindane concentration in blood 0.08-0.10 pg / l on increasing.

Analytical detection

The chemical- analytical detection in environmental samples, food and feed can be performed with chromatographic methods.

Wood preservative process

Due to the toxicity, especially by inhalation of wood preservatives (among Xylamon BV, Xyladecor ) in conjunction with pentachlorophenol, there was severe disease in humans. This was treated in Frankfurt wood preservative process.