Polychloro-biphenyls

PCB Polychlorinated biphenyls. Aka polychloro-biphenyls. Difficult to remediate chemical used in old-style transformers. Concentrated PCBs used to be referred to as "1268". 

Bunck, C.M., R.M. Prouty, and A.J. Krynitsky. 1987. Residues of organochlorine pesticides and polychloro-biphenyls in starlings (Stumus vulgaris), from the continental United States, 1982. Environ. Monitor. Assess. 8 59-75. 

Another development is due to the interest in polychlorodibenzofurans, spurred by their occurrence as environmental contaminants. Polychloro-phenols are manufactured in large amounts (150,000 tons per annum) and find a wide range of uses. The usual method of manufacture involves the hydrolysis of chlorobenzenes, and side reactions, favored by high temperature, can lead to the production of polychlorodibenzofurans and poly-chlorodibenzo-p-dioxins. The Seveso incident is well known." Polychloro-biphenyls are also widely used industrial chemicals, particularly in heat exchange systems, and their pyrolysis leads to the formation of polychloro-dibenzofurans. Polychlorodibenzofurans have also been detected in the fly ash and flue gases of incinerators and industrial heating plants. The most toxic of the polychlorodibenzofurans are 2,3,7,8-tetra-, 1,2,3,7,8-penta-, and 2,3,4,7,8-pentachlorodibenzofuran, and an extensive literature exists on the environmental pollution and the results of human exposure to these substances. A particularly tragic example of the latter occurred in 1968 in the Fukuoka prefecture of Japan after consumption of rice oil contaminated with a commercial polychlorobiphenyl. 

Lopshire [188] explored the exchange reaction of chlorine by oxygen with polychlorobiphenyl anions as a method of compound-selective polychloro-biphenyl congener detection in a gas chromatography-mass spectrometric system. Multiple reaction monitoring allowed separate chromatograms to be detected for each different polychlorobiphenyl composition from tetra-through nonachloro. 

The detection limit was estimated to be ca. 0.04ng L 1 of Arochlor 1016 from this source of water with Arochlors 1232, 1242 and 2154 having similar levels of detection. When the method was applied to potable water from a river source, the interference in the gas chromatogram from other organic compounds present in the sample made quantitation difficult at the lng L 1 level. The gas chromatography of polychloro biphenyls is also discussed in Table 15.11. 

When Aroclor 1268 (a commercial PCB fraction that contains a mixture of CI7, Clg, CI9, and Clio polychloro-biphenyls) is combined with excess O2 , the entire mixture is degraded. Samples taken during the course of the reaction confirm that (a) the most heavily chlorinated members react first (the initial nucleophihc addition is the rate-determining step) and (b) all components are completely dehalogenated. Tests with other PCB mixtures establish that those components with three or more chlorine atoms per phenyl ring are completely degraded by 02--, within several hours. 

J. de Boer, M. Lohman and E.A. Maier, The certification of the contents (mass fractions) of eight polychloro biphenyls (CB lUPAC No 28, 52, 118, 138, 149, 153, 170 and 180) in fresh mussel tissue — (CRM 682), Report EUR J78S9 EN. CEC Luxembourg (1999). Quantifying uncertainty in analytical measurement. English Edition. EURACHEM. DTI-VAM Crown Copyright 1995 UK, ISBN 0-948926-08-2 (1995). 

Baker, J.E., S.J. Eisenreich, and B.J. Eadie. 1991. Sediment trap fluxes and benthic recycling of organic carbon, polycyclic aromatic hydrocarbons, and polychloro-biphenyl congeners in Lake Superior. Environ. Sci. Technol. 25 500-509. 

Ross, R. A., and R. Lemay. 1987. Efficiencies of aluminum, magnesium and their oxides in the destruction of vapor-phase polychloro-biphenyls. Environ. Sci. Technol. 21(11) 1115-18. 

Choudry, G. G. and O. Hutzinger. 1984. Acetone-sensitized and nonsensitized pho-tolyses of tetra-, penta-, and hexachlorobenzenes in acetonitrile-water mixtures Photoisomerization and formation of several products including polychloro-biphenyls. Environ. Sci. Technol. 18, 235-241. 

Benzene J Other highly toxic polychloro-biphenyls... 

Another use of ultrasound in multiphase electrosynthetic systems concerns electrolytic dehalogenations for the destruction of environmental pollutants (p. 60). Electroreactions performed in microemulsions, micelles, and other multiphase media exploit the effect of ultrasound in the formation of the multiphase medium, and workers have tended not to look for any more subtle effects of ultrasound than just mechanical agitation. The major thrust of this work has concerned, in particular, the electrolytic dechlorination of polychloro-biphenyls and similar species. 

The determination of chlorinated insecticides and of polychloro-biphenyls is also discussed in Table 15.13. 

The capacity of Archaea to inhabit extreme habitats and their varied metabolic pathways may prove useful to society. For example, methane is a valuable source of energy and already its release from landfill sites is being harnessed in some countries to provide energy for domestic consumption. Other Archaea may be valuable for the bioremediation of polluted areas because they prefer highly acidic or highly alkaline media and several species degrade organic molecules such as polychloro biphenyls (PCBs) while others can extract heavy metals from waste materials. 

Benzene monoxide-oxepin and its sulfur analog are treated elsewhere (Chapter 5.1.7) (67AG(E)385). However, we point out here that electron-withdrawing substituents often favor the benzene oxide tautomer. The first study on oxides of the environmentally hazardous polychloro- and polybromo-biphenyls shows that they exist mainly in the benzene oxide form (81JOC3721). Oxides of polynuclear aromatic hydrocarbons (PAH) also exist mainly in the fused-ring oxirane form. 

Mizutani and coworkers57a confirmed the presence of polychloro(methylsulfonyl)biphenyls (159-170) as sulfur-containing metabolites of chlorobiphenyls (Cl-BP) in the feces of mice based on both GLC-mass spectrometry and chemical derivatization. In some cases comparison with authentic samples (161 and 162) was also made. When preparing 161 and 162,2,5-dichloro-3-(methylsulfonyl)aniline, 2,5-dichloro-l-iodo-3-(methylsulfonyl)benzene and 2,2, 5,5 -tetrachloro-3,3 -bis(methyl-sulfonyl)biphenyl were also obtained and their four peak El mass spectra reported572. Similar data were given for the corresponding 4-substituted intermediates, which were involved in the preparation of 162. Also 2,4, 5-trichloro-2 -(methylsulfonyl)-biphenyl was prepared and its four peak mass spectra given. Metabolites 163 and 164 were also identified by comparison with the authentic standards. 

Schafer W, Ballschmiter K. 1986. Monobromo-polychloro-derivatives of benzene, biphenyl, dibenzofiiran, and dibenzodioxin formed in chemical-waste burning. Chemosphere 15 755-763. 

AROCLOR 1232 AROCLOR 1242 AROCLOR 1248 AROCLOR 1254 AROCLOR 1260 AROCLOR 1262 AROCLOR 1268 AROCLOR 2565 AROCLOR 4465 AROCLOR 5442 BIPHENYL, POLYCHLORO- CHLOPHEN CHLOREXTOL CHLORINATED BIPHEN1X CHLORINATED DIPHENYL CHLORINATED DIPHENYLENE CHLORO BIPHENYL... 

BIPHENYL, POLYCHLORO- see PJL750 BIPHENYL SELENIUM see PGH250 3,3, 4,4 -BIPHENYLTETRAMINE see BGK500 3,3, 4,4 -BIPHENYLTETRAMINE TETRAHYDROCHLORIDE see BGK750 N-(4-BIPHENYLYL)ACETAMIDE see PDY500 N,N -4,4 -BIPHENYLYLENEBISACETAMIDE see BFXOOO... 

These results confirm our hypothesis, and prove the essential role of polychlorinated gem-dichlorocyclohexadienones as reaction intermediates which can react to give either noble products (chlorinated phenols in meta), or unwanted condensation products (polychloro phenoxy phenols, polychloro dihydroxy biphenyls, etc.). 

Polychlorinated Biphenyl Chlorinated Biphenyl Halogenated Waxes PCB Polychloro- Polyphenyls ... 

The reactivity of a heteroexcimer has been exploited as a means of degrading low concentrations of chlorinated pollutants such as polychlorinated biphenyls and polychlorinated benzenes. Copolymers of vinylnaphthalene and styrenesulfonic acid form water-soluble, miceUar-hke copolymers with a hydro-phobic core. When the nonpolar chloro-compounds are dissolved in aqueous solutions containing the water-soluble copolymer, they are scavenged into the core, where they undergo photodehalogenation. In these reactions, essentially all the incident radiation is absorbed by the naphthalene chromophores, which form heteroexcimers with the polychloro-compound. The pattern of dechlorination is characteristic of electron transfer rather than direct homolysis. 

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