Benzene Lindane

Toxic Effects on the Blood-Forming Tissues Reduced formation of erythrocytes and other elements of blood is an indication of damage to the bone marrow. Chemical compounds toxic to the bone marrow may cause pancytopenia, in which the levels of all elements of blood are reduced. Ionizing radiation, benzene, lindane, chlordane, arsenic, chloramphenicol, trinitrotoluene, gold salts, and phenylbutazone all induce pancytopenia. If the damage to the bone marrow is so severe that the production of blood elements is totally inhibited, the disease state is termed aplastic anemia. In the occupational environment, high concentrations of benzene can cause aplastic anemia. 

Fiuoronitro- benzene lindane 23 7 2 Not resistant plastic severely crazed softened or dissolved Chemical resistance per ASTM D543 Lustran Monsanto Specimen 50.8 mm (2 in) diameter discs... 

Fluoronitro- benzene lindane 22 7 2 Not resistant plastic severely crazed softened or dissolved ... 

Chemical Benzene Hexach loro-benzene Lindane B(a)P Nickel Copper... 

Benzene Hexachloride and Lindane. The active constituent of ben2ene hexachloride is y-l,2,3,4,5,6-hexachlorocydohexane [58-89-9] or lindane (31). 

Many very hazardous solvents, such as benzene and carbon tetrachloride, were widely used until the 1970s. The situation was very similar for the use of pesticides. Among the toxic pesticides that were still in wide use 20 years ago were chlorophenols, DDT, lindane, and arsenic salts, all of which are classified as human carcinogens as well as being acutely toxic. Fortunately, use of these kinds of very toxic chemicals is now limited in the industrialized world. However, because the number of chemicals used in various industries continues to increase, the risks of long-term health hazards due to long-term exposure to low concentrations of chemicals continues to be a problem in the workplace. 

That benzene hexachloride isomer mixture is then the raw material for lindane production. The production of lindane per se is not a chemical synthesis operation but a physical separation process. It is possible to influence the gamma isomer content of benzene hexachloride to an extent during the synthesis process. Basically, however, one is faced with the problem of separating a 99%-plus purity gamma isomer from a crude product containing perhaps 12 to 15% of the gamma isomer. The separation and concentration process is done by a carefully controlled solvent extraction and crystallization process. One such process is described by R.D. Donaldson et al. Another description of hexachlorocyclohexane isomer separation is given by R.H. Kimball. 

HCH, sometimes misleadingly termed benzene hexachloride (BHC), exists in a number of different isomeric forms of which the gamma isomer has valuable insecticidal properties. These were discovered during the 1940s, and HCH came to be widely used as an insecticide to control crop pests and certain ectoparasites of farm animals after the Second World War. Crude technical BHC, a mixture of isomers, was the first form of HCH to be marketed. In time, it was largely replaced by a refined product called lindane, containing 99% or more of the insecticidal gamma isomer. 

The first commercially available HCH insecticide sometimes misleadingly called benzene hexachloride (BHC) was a mixture of isomers, principally alpha HCH (65-70%), beta HCH (7-10%), and gamma HCH (14-15%). Most of the insecticidal activity was due to the gamma isomer (Figure 5.1), a purified preparation of which (>99% pure) was marketed as lindane. In Western countries, technical HCH was quickly replaced by lindane, but in some other countries (e.g., China) the technical product, which is cheaper and easier to produce, has continued to be used. HCH has been used as a seed dressing, a crop spray, and a dip to control ectoparasites of farm animals. It has also been used to treat timber against wood-boring insects. 

The formulations shown in Table I were made to contain approximately 3 parts of 7-benzene hexachloride to 5 parts of technical DDT, because this is the ratio in which they have been present in many of the formulations encountered by the author. For these ratios the separation and recovery of 7-benzene hexachloride and DDT are satisfactory. However, if the ratio of 7-benzene hexachloride to DDT is increased much beyond 3 to 5, a small amount of impurity from the technical benzene hexachloride contaminates the DDT fraction and leads to high DDT results. This is not the case with lindane-DDT mixtures, as will be seen by the results in Table I. Because pure 7-benzene hexachloride and DDT separate so widely on the column, it should be possible to separate and determine these two ingredients in almost all proportions. 

Fig. 5. Relationship between the distribution (partition) coefficient on dimethyl dihydrogenated tallow montmorillonite for a range of non-ionic organic pollutants and their corresponding solubility in water. BHC is benzene hexachloride, the y-isomer of which is known as lindane aroclor 1232 and aroclor 1252 denote mixtures of polychlorinated biphenyls containing about 32 and 52% chlorine, respectively. After Beall (2003).

Aspila et al. [338] reported the results of an interlaboratory quality control study in five laboratories on the electron capture gas chromatographic determination of ten chlorinated insecticides in standards and spiked and unspiked seawater samples (lindane, heptachlor, aldrin, 5-chlordane, a-chlordane, dield-rin, endrin, p, p -DDT, methoxychlor, and mirex). The methods of analyses used by these workers were not discussed, although it is mentioned that the methods were quite similar to those described in the water quality Branch Analytical Methods Manual [339]. Both hexane and benzene were used for the initial extraction of the water samples. 

Lindane, a widespread insecticide constituted of technical mixtures of hexa-chlorocyclohexane (HCH), was dechlorinated using Pd/C, Pt/C, or Raney-Ni. The product using the multiphasic system was benzene, obtained within 1 hour. The base initially promoted HCl ehmination from HCH to yield trichlorobenzene, which then underwent the usual hydrodechlorination reaction. 

Synonyms AI3-09232 Benzene hexachloride-a-isomer a-Benzene hexachloride BRN 3195880 CCRIS 327 EINECS 206-270-8 ENT 9232 a-HCH a-Hexachloran a-Hexachlorane a-EIexachlorcyclohexane a-Hexachlorocyclohexane 1,2,3,4,5,6-Hexachloro-a-cyclohexane la,2a,3p,4a,5p,6p-Hexachlorocyclohexane a-1,2,3,4,5,6-Hexachlorocyclohexane a-Lindane ... 

Synonyms AI3-09233 te/js-a-Benzene hexachloride p Benzene hexachloride Benzene-cA-hexachloride BRN 1907338 CCRIS 328 EINECS 206-271-3 ENT 9233 p-HCH P-Hexa-chloran pHexachlorobenzene la,2p,3a,4p,5a,6p-Hexachlorocyclohexane pHexachloro-cyclohexane 1,2,3,4,5,6-Hexachloro-P-cyclohexane l,2,3,4,5,6-Hexachloro-to/3s-cyclohexane p i,2,3,4,5,6-Hexachlorocyclohexane P-Isomer P-Lindane TBH UN 2761. 

Soil. Lindane degraded rapidly in flooded rice soils (Raghu and MacRae, 1966). In moist soils, lindane biodegraded to (y-PCCH) (Eisner et al., 1972 Kearney and Kaufman, 1976 Fuhremann and Lichtenstein, 1980). Under anaerobic conditions, degradation by soil bacteria yielded y-BTC and a-BHC (Kobayashi and Rittman, 1982). Other reported biodegradation products include pentachlorocyclohexane, pentachlorobenzene, tetrachlorocyclohex-l-enes, and tetrachloro-benzenes (Moore and Ramamoorthy, 1984). Incubation of lindane for 6 wk in a sandy loam soil under flooded conditions yielded y-TCCH, y-2,3,4,5,6-pentachlorocyclohex-l-ene, and small amounts of 1,2,4-trichlorobenzene, 1,2,3,4-tetrachlorobenzene, 1,2,3,5-, and/or 1,2,4,5-tetrachloro-benzene (Mathur and Saha, 1975). Incubation of lindane in moist soil for 8 wk yielded the follow-... 

When lindane in hydrogen-saturated deionized water was exposed to a slurry of palladium catalyst (1%) at room temperature, benzene and chloride ions formed as the final products (Schiith... 

Benzenediol, see Hydroquinone p-Benzenediol, see Hydroquinone Benzeneformic acid, see Benzoic acid Benzene hexachloride, see Lindane Benzene hexachloride-a-isomer, see a-BHC Benzene-crs-hexachloride, see p-BHC Benzene-y-hexachloride, see Lindane a-Benzene hexachloride, see a-BHC p-Benzene hexachloride, see p-BHC 6-Benzene hexachloride, see 8-BHC y-Benzene hexachloride, see Lindane frans-a-Benzene hexachloride, see p-BHC Benzene hexahydride, see Cyclohexane Benzene methanoic acid, see Benzoic acid Benzene methanol, see Benzyl alcohol Benzene tetrahydride, see Cyclohexene Benzenol, see Phenol... 

EPA pesticide chemical code 000169, see Amyl acetate EPA pesticide chemical code 000601, see Acrylonitrile EPA pesticide chemical code 000701, see Acrolein EPA pesticide chemical code 001502, see sec-Butyl alcohol EPA pesticide chemical code 004101, see Acetone EPA pesticide chemical code 005302, see Ammonia EPA pesticide chemical code 008801, see Benzene EPA pesticide chemical code 009001, see Lindane EPA pesticide chemical code 009101, see Benzoic acid EPA pesticide chemical code 009502, see Benzyl alcohol EPA pesticide chemical code 009601, see Oxalic acid EPA pesticide chemical code 010901, see p-Propiolactone EPA pesticide chemical code 011301, see l,2-Dibromo-3-chloropropane... 

Benzazimide, see Azinphos-methvl Benzene, see Chlorobenzene, Cyclohexane, Diallate, Diethyl phthalate, Hexachlorobenzene, 1-Hexene, Lindane, Pentachlorobenzene, Styrene, Triallate. 1,2,3-Trichlorobenzene... 

Chlorination of benzene gives an addition product that is a mixture of stereoisomers known collectively as hexachlorocyclohexane (HCH). At one time, this was incorrectly termed benzene hexachloride. The mixtnre has insecticidal activity, though activity was found to reside in only one isomer, the so-called gamma isomer, y-HCH. y-HCH, sometimes under its generic name lindane, has been a mainstay insecticide for many years, and is about the only example of the chlorinated hydrocarbons that has not been banned and is still available for general use. Although chlorinated hydrocarbons have proved very effective insecticides, they are not readily degraded in the environment, they accumulate and persist in animal tissues, and have proved toxic to many bird and animal species. 

Vast quantities of petroleum benzene have been used in the manufacture of such widely used agricultural chemicals as benzene hexachloride and lindane, the essentially pure gamma isomer of 1,2,3,4,5,6-hexachlorocyclohexane. 

BENZENE HEXACHLORIDE Gamniexane, Lindane Poisonous liquid or solid, Class B 2 1 0... 

The other major dehalogenation pathway involves elimination of two halogens, leaving behind a pair of electrons that usually goes to form a carbon-carbon double bond. Where the pathway involves halogens on adjacent carbons, it is known as vicinal dehalogenation or reductive -elimination. The major pathway for reductive transformation of lindane involves vicinal dehalogenation, which can proceed by steps all the way to benzene (28). Recently, data has shown that this pathway not only can convert alkanes to alkenes, but can produce alkynes from dihaloalkenes (29). 

Baker MT, Nelson RM, Van Dyke RA. 1985. The formation of chlorobenzene and benzene by the reductive metabolism of lindane in rat liver microsomes. Arch Biochem Biophys 236 506-514. 

In the case of lindane, the lack of chlorinated intermediates indicate direct transformation to benzene. (Figure 5, Schiith and Reinhard 1998)... 

Figure 5. Transformation pathway of lindane to benzene. Reprinted from Applied Catalysis B Environmental, Vol. 18, Schtlth and Reinhard, Hydrodechlorination and Hydrogenation of Aromatic Compounds over Palladium on Alumina in Hydrogen-Saturated Water, pp. 219, Copyright 1998, with permission from Elsevier Science.

The gamma isomer of hexachlorocyclohexane was commonly called gamma benzene hexachloride, which was a misnomer, since no benzene ring is present in this compound. Lindane is an effective pediculicide and scabicide. 

Hexachlorocyclohexane, once confusingly called benzene hexachloride (BHC), consists of several stereoisomers with different orientations of H and Cl atoms. The gamma isomer is shown in Figure 16.5. It is an effective insecticide, constituting at least 99% of the commercial insecticide lindane. 

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