Polychlorinated naphthalene
Polychlorinated naphthalenes ( PCNs ) are chlorinated hydrocarbons which are produced by the chlorination of naphthalenes.
Nomenclature
The 75 isomeric PCN are referred to in the art and toxicology with an abbreviation PCN - X, where X can be a number 1-75. So called PCN PCN 48 or 48 the substance 2,3,6,7 - tetrachloronaphthalene. Mixtures of PCNs are often defined by the juxtaposition of the isomers contained therein: PCN-33/34/37, PCN 28/43 or PCN-38/40.
Properties
Chemical Properties
The empirical formula is C10H8 - nCln, where n can be at most 8. As with dioxins and polychlorinated biphenyls ( PCBs) are different congeners of PCNs. Of the 75 theoretically possible congeners with one to eight chlorine atoms are used in technical PCN products 67. Almost all products contain a mixture of different isomers.
Use
PCN have insecticidal and fungicidal properties and are therefore used in wood preservatives. For ships them as additives for water-proof metal colors. In addition, they are used as substitutes for polychlorinated biphenyls in synthetic resins and sealants, as flame retardants and use as plasticisers. The estimated global production of PCN was until 1998, at 150,000 tonnes, with production in most countries has been severely restricted since 1970. PCN was formerly in smoke ammunition use. The possible consequences of emissions of PCN and similar substances from smoke ammunition into the environment describes a long time under lock held document of the Swiss Army: The ammunition used in fogging exercises during the Second World War resulted due to severe symptoms of poisoning for compulsory slaughter of 15,000 cattle.
Biological significance and toxicity
PCN can - like other chlorinated hydrocarbons (eg, pentachlorophenol, polychlorinated dibenzodioxins and dibenzofurans ) - cause chloracne. After direct skin contact with chlorinated naphthalenes or their Staubsublimaten it comes in addition to typical skin lesions also cause nervousness, weight loss and anemia; inhalation dystrophy is also possible. To designate the intoxicating effects of Perna 's disease in 1918, derived from Perchlornaphtalin the name coined.
Tests with pigs, cows, rats and sheep showed that the toxic effects with increasing number of chlorine atoms increases. Mono-, di - and trichlorinated compounds showed no or little toxicity, tetra-and higher chlorinated naphthalenes also resulted in lower doses to systemic disease until death of the animals.
PCN are under consideration to be received as persistent organic pollutants in the Stockholm Convention.