A facile method for the dechlorination of mono- and dichlorobiphenyls using Raney Ni–Al alloy in dilute aqueous solutions of alkali hydroxides or alkali metal carbonates

Raney Ni–Al alloy in a dilute aqueous alkaline solution of NaOH, KOH, CsOH, LiOH, or Ca(OH) 2 or of alkali metal carbonates such as Na2CO3, K2CO3 becomes a very powerful reducing agent and dechlorinates the polychlorobiphenyl(PCB) congeners mono- and dichlorobiphenyls effectively to afford biphenyl and/or phenylcyclohexane, respectively. The reactions are run under mild conditions without the use of organic solvents. The reductive dechlorination of dichlorobiphenyls with a Raney Ni–Al alloy under ultrasonication was investigated, also.