Catalytic carbonylation: A new process for recycling polychlorobiphenyls

Boyarskii, V. P.; Zhesko, T. V.; Lanina, S. A.; Nikiforov, Vladimir; Tereshchenko, G. F.

doi:10.1134/s2070050409030076

Cited by 4 publications

(1 citation statement)

References 5 publications

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“…Considering the data on the carboxylation of PCB congeners [18], we may assume that the mono-and dimethoxy derivatives based on the PCB 101 (2,4,5,2',5'-pentachlorobiphenyl) are formed through the attack of the nucleophile only on the most substituted ring.…”

Section: Condensation Componentsmentioning

confidence: 99%

Reactivity features of polychlorobiphenyl congeners in the nucleophilic substitution reactions

et al. 2012

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Groups of congeners and individual congeners of polychlorobiphenyls contributing to the composition of the technical mixture "Sovol" (PCB 60, PCB 64, PCB 70, PCB 74, PCB 97, PCB 101, PCB 105, PCB 110, PCB 118, PCB 138, PCB 149, PCB 156, and PCB 163) were synthesized by the reaction of aryl-aryl coupling. The interaction of the congeners with sodium methoxide was performed and their complete conversion was proved. By means of gas chromatography-mass spectrometry the PCBs methoxy derivatives were identified. The data on the reactivity of the individual polychlorobiphenyl congeners were precised.The problem of disposal of technogenic polychlorinated biphenyls (PCBs) is still relevant, since there is no universal method of disposal of this toxic material. At the same time, the previously developed methods of chemical treatment of PCBs continue to be improved, which brings new positive results. For example, the use of the nanosized Pd and/or Fe catalysts in the processes of reductive dehalogenation of the PCB congeners in some cases leads to comprehensive conversion (100%) of the principal compounds [1-8]. As a rule, the dehydrohalogenation of the highly chlorinated congeners results in a mixture of rather less chlorinated biphenyls, and these methods can serve as a preliminary stage to biodegradation of the chlorinated products and the subsequent removal of chlorine atoms from the substrate.The stage of preliminary preparation of PCBs for disposal can also be performed using reactions of nucleophilic substitution of chlorine atoms in the PCB congeners [9].We have shown previously that in the reaction of technical mixtures of the PCBs of "Sovol" brand with sodium methoxide the most reactive congeners are hexa-and pentachlorobiphenyls, while tetra-and trichlorobiphenyls are less reactive [10]. In this reaction the hexachlorobiphenyls (PCB 128, PCB 132, PCB 138, PCB 149, PCB 153, and PCB 156) were transformed into di-and trimethoxy derivatives, the pentachlorobiphenyls (PCB 82, PCB 85, PCB 87, PCB 91, PCB 95, PCB 97, PCB 99, PCB 101, PCB 105, PCB 110, and PCB 118), into mono-, di-and trimethoxy derivatives (to a low extent), tetrachlorobiphenyls (PCB 41, PCB 47, PCB 49, PCB 56, PCB 60, PCB 64, PCB 66, PCB 70, and PCB 74), into mono-and dimethoxy derivatives (to a low extent), trichlorobiphenyls (PCB 28 and PCB 33) into monomethoxy derivatives (partially). Using the method of internal normalization in the gas chromatographic (GC) analysis with a flame ionization detector (FID) we found that the amount of the congeners non-reacted with sodium methoxide, mostly three-and tetrachlorobiphenyls, was 8-15%.Given that Sovol is a mixture of 30 PCB congeners [11,12], the results of the study [10] are approximate and practically do not give information on the most reactive C-Cl bonds in the structures of individual chlorinated biphenyls within a single series of isomers. The error in determining the number and types of methoxy derivatives of PCBs in [10] appears both due to the different responses of the flame-ionization dete...

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Section: Condensation Componentsmentioning

confidence: 99%