Naphthalenes dichlorinated

The corresponding catalytic version of this reaction was performed using either naphthalene- or biphenyl-supported polymers 594 or 595, respectively, which were prepared by cross-coupling copolymerization of 2-vinylnaphthalene or 4-vinylbiphenyl with vinyl-benzene and divinylbenzene promoted by AIBN in THF and polyvinyl alcohoP . These polymers have been used as catalysts (10%) in lithiation reactions involving either chlorinated functionalized compounds or dichlorinated materials in THF at —78°C and were re-used up to ten times without loss of activity, which is comparable to the use of the corresponding soluble arenes. 

The most abundant contaminant was 1-chloronaphthalene with concentrations up to 750 pg/L followed by dichlorinated naphthalenes with concentrations up to 98 pg/L in total. The isomeric pattern of the dichloronaphthalenes as illustrated in Fig. 3 is very similar to technical mixtures like Halowax 1000, 1031 or Basileum SP-70. Chlorinated naphthalenes are known environmental contaminants. However, mainly the occurrence of the higher chlorinated congeners has been reported (Falandysz, 1998, and references cited therein). Only few investigations detected lower chlorinated compounds in the aquatic environment (Falandysz, 2003 Schwarzbauer et al., 2001). 

The strong decrease of concentrations from sample B to C might suggest strong influence of sorption to organic matter in particular, if the relative high Koc - values of mono- and dichlorinated naphthalenes (between 3.9 and 4.8, Jakobsson and Asplund, 2000) and the PAHs identified are considered (approx. 3.5 to 4.5, Schwarzenbach et al., 1993). 

A second group of specific xenobiotics in Teltow Canal sediments are halogenated aromatics. Several chlorinated and brominated mono- and diaromatic hydrocarbons were detected in high amounts within the extractable organic matter as reported previously (Schwarzbauer et al. 2001). The halogenated arenes identified in the hydrolysis extracts included mono- and dichlorinated naphthalenes 12+13. mono- and dihrominated naphthalenes 14+15. tetra- to hexachlorinated biphenyls (PCB) and 2,4,6-tribomoaniline. The peak pattern of the chlorinated naphthalenes was similar to the congener distribution in technical mixtures e.g. Halowax 1000 (Falandysz 1998). 

Halogenated naphthalenes in Teltow Canal sediments are specific pollutants reflecting the industrial point source emission. Chlorinated naphthalenes are known environmental pollutants, which are emitted due to their usage as technical additives, as a result of pyrolytic processes or as an impurity associated with PCB products (Haglund et al. 1993 Jamberg et al. 1993). In the extractable fraction mono- and dichlorinated naphthalenes were determined with total concentrations between 120 and 493 pg/kg. The peak pattern was similar to the congener distribution of technical mixtures (Halowax 1000, Halowax 1001) (Falandysz 1998). The concentration of 1-bromonaphthalene ranged between the limit of quantification (LOQ) and 250 pg/kg (see Table 1). 

A second study characterizing a huge groundwater contamination caused by chemicals used for wood impregnation revealed mono- and dichlorinated naphthalenes, chlorobenzo(b)thiophene, acenaphthene and methylated naphthalenes as the main pollutants. Anaerobic microbial degradation of the main pollutant 1-chloronaphthalene was evident from identification of 1 -chloro-4-naphthol and 1-chloronaphthoic acid as biotic transformation products. In contrast inorganic and compound specific stable carbon isotope analyses indicated only a minor degree of microbial transformation. Thus, sorption seemed to be the main attenuation process within the aquifer affected by the coal tar based contamination described above. 

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