Reduction of α-ω dibromoalkanes on aluminium and mercury cathodes

Abstract

1,3-Dibromopropane and 1,4-dibromobutane have each been reduced from non-aqueous solutions of quaternary ammonium salts on cathodes of mercury and aluminium. Product analysis and kinetic measurements have shown that reduction on mercury proceeds through adsorbed radicals whereas on aluminium products are explained in terms of free radical reactions initiated by solvated electrons. Products on mercury include solid organomercury polymer and dibutylmercury from dibromobutane and by contrast cyclopropane and propane from dibromopropane. The difference is explained in terms of the kinetic facility of formation of cyclopropane and the greater stability of the adsorbed butyl diradical relative to its propyl analogue. Products on aluminium cathodes include higher bromides and dibromides.