THE INDIRECT ANODIC-OXIDATION OF 2-METHYLNAPHTHALENE .2. OXIDATION INPRESENCE OF DICHROMATE

Tetrabutylammonium dichromate and ammonium dichromate enhance the elec trooxidation of naphthalene and 2-methylnaphthalene (I) to 1,4-naphtho quinone and 2-methyl-1,4-naphthoquinone (II) and the oxidation is furt her improved by co-catalysis of RuCl3.3H2O. The present results imply that the role of Cr2O72- anion in solution is mainly as a bulk oxidati on agent which under the applied cell potential forms a concentration excess at the anode. It can therefore be used in low concentrations co mpared to those usually required for oxidation and low potentials are sufficient to give maximum effect. Selectivity for II is improved to > 60% and is obtained in an undivided cell.