By any other name, lindane is the 99% pure gamma isomer of hexachlorocyclohexane. It was introduced as a pediculicide and scabicide in 1952 as Kwell by Reed and Carnrick. The Pharmaceutical Manufacturing Encyclopedia describes the manufacturing process of lindane as one in which chlorine gas is gradually passed into 660 parts of benzene (a known carcinogen) until 890 parts of the gas has been absorbed. The mixture is stirred continuously and the temperature is maintained at 15 degrees C to 20 degrees C.

The supply of chlorine is then interrupted and the precipitated solid filtered off and dried. In weight, it is found to be equivalent of 900 parts. The mother liquid is then mixed with 330 parts of benzene and the mixture again treated with 890 parts of chlorine in the manner described. After filtering the reaction mixture resulting from the second chlorination, the filtrate is again mixed with a smaller quantity of benzene and again chlorinated in a similar manner. In this way, a continuous process for the preparation of benzene hexachloride results.

This benzene hexachloride isomer mixture is then the raw material for lindane production.
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Methods of Manufacturing:

gamma-HCH is isolated by selective crystallization of crude HCH.
[Tomlin, C.D.S. (ed.). The Pesticide Manual - World Compendium, 11 th ed., British Crop Protection Council, Surrey, England 1997 665]**PEER REVIEWED**

Lindane is extracted from HCH by use of selected solvents, the most common ... is methanol. The gamma-isomer so obtained is treated with nitric acid to remove odor.
[IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Man. Geneva: World Health Organization, International Agency for Research on Cancer,1972-PRESENT. (Multivolume work).,p. V20 201 (1979)]**PEER REVIEWED**

Prepared by treating crude benzene hexachloride with methanol or acetic acid in which the alpha- and beta-isomers are nearly insoluble, followed by chromatographic adsorption or fractional crystallization.
[Gerhartz, W. (exec ed.). Ullmann's Encyclopedia of Industrial Chemistry. 5th ed.Vol A1: Deerfield Beach, FL: VCH Publishers, 1985 to Present.,p. VA14 280]**PEER REVIEWED**

Benzene + chlorine (photochlorination/isomer separation).
[Ashford, R.D. Ashford's Dictionary of Industrial Chemicals. London, England: Wavelength Publications Ltd., 1994. 539]**PEER REVIEWED**
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Impurities:

Commercial lindane available in the US contains minimum of 99.9% (by wt) of gamma-isomer. The remaining 0.1% consists of other unspecified isomers of HCH.
[IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Man. Geneva: World Health Organization, International Agency for Research on Cancer,1972-PRESENT. (Multivolume work).,p. V20 199 (1979)]**PEER REVIEWED**

Crude benzene hexachloride consists of 10-18% of the gamma-isomer, 55-70% of the alpha- isomer, 5-14% of the beta-isomer, 6-8% of the delta-isomer, 3-4% of the epsilon-isomer, and a trace of the eta-isomer. A heptachlorocyclohexane and an octachlorocyclohexane are present as impurities and contribute to the unpleasant odor of benzene hexachloride.
[Gerhartz, W. (exec ed.). Ullmann's Encyclopedia of Industrial Chemistry. 5th ed.Vol A1: Deerfield Beach, FL: VCH Publishers, 1985 to Present.,p. VA14 280]**PEER REVIEWED**

Mechanism of Action:

ITS MODE OF ACTION IS UNKNOWN BUT SPECIFIC TOXICITY OF GAMMA-ISOMER SUGGESTS THAT ... IT MAY INTERACT WITH PORES OF LIPOPROTEIN STRUCTURE OF INSECT NERVE CAUSING DISTORTION & CONSEQUENT EXCITATION OF NERVE IMPULSE TRANSMISSION.
[White-Stevens, R. (ed.). Pesticides in the Environment: Volume 1, Part 1, Part 2. New York: Marcel Dekker, Inc., 1971. 87]**PEER REVIEWED**
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European/International Regulations 
European Labeling in Accordance with EC Directives Hazard Symbols:
 T N Risk Phrases: 
R 23/24/25 Toxic by inhalation, in contact with skin and if swallowed. 
R 36/38 Irritating to eyes and skin.
R 50/53 Very toxic to aquatic organisms; may cause long-term adverse effects in the aquatic environment. 
Safety Phrases: 
S 13 Keep away from food, drink and animal feeding stuffs. 
S 45 In case of accident or if you feel unwell, seek medical advice immediately (show the label where possible). 
S 60 This material and/or its container must be disposed of as hazardous waste. 
S 61 Avoid release to the environment. Refer to special instructions/Safety data sheets.

US DOT Shipping Name: ORGANOCHLORINE PESTICIDE,SOLID,TOXIC (RQ, LINDANE) Hazard Class: 6.1 UN Number: UN2761 Packing Group: III

What is lindane?

For basic information see Lindane:2761.

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