3,4 ,5-Trichlorobiphenyl PCB

Common Name 2,3,4-Trichlorobiphenyl Synonym PCB-21, 2,3,4-trichloro-l,l -biphenyl Chemical Name 2,3,4-trichlorobiphenyl CAS Registry No 55702-46-0 Molecular Formula C12H7C13 Molecular Weight 257.543 Melting Point (°C) ... 

The entire set of 209 PCBs forms a set of congeners. When PCBs are subdivided by the degree of chlorination (the parameter n" in the above formula), the term isomer group is used. For example, the 24 different PCB compounds with three chlorine atoms are called the trichlorobiphenyl isomer group. PCBs of a given isomer group with different chlorine substitution positions are called isomers. Thus, 2,4,4 -trichlorobiphenyl and 2, 3,4-trichlorobiphenyl are two of the 24 trichlorobiphenyl isomers. PCB nomenclature is summarized in Table 1. 

Photolytic. PCB-1260 in a 90% acetonitrile/water solution containing 0.2 to 0.3 M sodium borohydride and irradiated with UV light (X = 254 nm) reacted to yield dechlorinated biphenyls. After 2 h, about 75% of the congeners were destroyed. Without sodium borohydride, only 10% of the congeners had reacted. Products identified by GC include biphenyl, 2-, 3- and 4-chlorobiphenyl, six dichlorobiphenyls, three trichlorobiphenyls, l-phenyl-l,4-cyclohexadiene, and l-phenyl-3-cyclohexene (Epling et ah, 1988). 

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