Method for removing polychlorinated biphenyls from transformer oil

A method for effecting the removal of polychlorinated biphenyls from contaminated transformer oil having up to 1% by weight of polychlorinated biphenyl, and less 60 ppm of water which comprises

• (1) directly adding to the transformer oil under an inert atmosphere, while it is being agitated, finely divided sodium metal, an oil soluble electron carrier selected from the class consisting of benzophenone, alkylated benzophenone, naphthylene, alkyl naphthylene, biphenyl and alkyl biphenyl, and an aprotic complexing solvent selected from the class consisting of tetrahydrofuran, ethyleneglycoldimethylether, diethyleneglycoldimethylether, oligomeric ethyleneglycoldialkylether, dimethylformamide and hexamethylphosphoramide, and
• (2) continuing the agitation of the resulting mixture until the polychlorinated biphenyl content of the resulting mixture is reduced to less than 50 ppm,
• where the aforementioned ingredients of (1) are utilized in proportions sufficient to produce a mixture having an initial concentration of 0.1-2% of the finely divided sodium metal, 0.1 to 1% of oil soluble electron, and 1-10% of the aprotic complexing solvent, based on the weight of the mixture.