ABSTRACT
Several groups have reported the infrared (ir) and Raman spectra of biphenyl and some of its deuterated analogs. Using specifically deuterated moieties, it was also possible to assign the specific contributions of the individual hydrogen atoms of the biphenyl nucleus. Biphenyl appears to be planar in the solid state but the configuration of biphenyl in solution has not unequivocally been ascertained. The ir spectra of 4,4'-dichlorobiphenyl and several other disubstituted biphenyls have also been investigated. Comparison of the ir spectra of 2,2',5,5'- and 2,2',4,5'-tetrachlorobiphenyl with the Aroclor fraction clearly indicates that the 2,2',5,5' isomer is the major component with the minor constituent being the 2,2',4,5' isomer. The characteristic ir spectra of polychlorinated biphenyls (PCB) isomers particularly in the 1,200 to 300 cm-1 region which denotes the aromatic C-H bending vibrations and deformations as well as the C-Cl stretching vibrations are a useful analytical tool for the identification of the components of complex commercial PCB formulations.
