Debromination of 1,4-dibromobenzene and 4,4'-dibromobiphenyl: A model for cleansing of PCBs

Abstract

The aim of this study is to develop a. catalytic method which has advantages over current methods to detoxify and degrade environmentally harmful polychlorinated biphenyls (PCBs). A variety of catalysts have been employed in a preliminary study on 1,4-dibromobenzene and 4,4'-dibromobiphenyl which may be considered to represent simple analogues of PCBs. The most satisfactory catalysts are those involving (Pd(dppf)] [dppf = 1,1'-bis(diphenylphosphino)ferrocene], generated in situ from PdCl2(dppf) or Pd(dppf)2. In the presence of the reducing reagent, namely NaBH4, debromination has been achieved at relative mild conditions with high product yields (> 70%). Thus, our results indicate the possibility of dechlorination of PCBs with such catalysts.