ELECTROHYDROGENATION OF A NITROBENZODIOXANE AND A NITROBENZODIOXOLANE AT RANEY TYPE ELECTRODES IN A BASIC HYDROETHANOLIC SOLUTION:ELECTRONATION-PROTONATION OR ELECTROCATALYTIC HYDROGENATION ?

摘要

Electrocatalytic hydrogenation (ECH) at Raney type electrodes is a mild method for hydrogenating a variety of functional groups in slightly acidic (pH > 3),neutral or basic aqueous or hydroorganic media [1].It involves the reaction of chemisorbed hydrogen,M(H),with the adsorbed organic substrate,M(R),as in catalytic hydrogenation [M(R) + 2M(H) ->RH_2 + M],except that M(H) is generated by reduction of water [2H_2O/H_3O~+ + 2e~- + M -> 2M(H) + 2HO~-/H_2O where M represents the electrode surface].