Electrocatalytic hydrogenation of m-xylene on platinized-platinum electrodes

The electrocatalytic hydrogenation of m-xylene (1,3-dimethylbenzene) was in vestigated at room temperature in 0.5 M H2SO4 solutions on a platinized-pla tinum (Pt/Pt) electrode. It was found that the hydrogenation process of m-x ylene took place only in the potential region corresponding to the weakly a dsorbed hydrogen (0 < E-H < 0.25 V) and that the electrocatalytic activity of the Pt/Pt electrode was dependent on the hydrogenation potential. The hy drogenation of m-xylene yielded steroisomeric product mixtures of the satur ated 1,3-dimethylcyclohexane (1,3-DMCH), cis- and trans-1,3-DMCH. The cis/t rans isomer ratio was found to be strongly dependent on the potential on wh ich the hydrogenation of m-xylene has been carried out. These results were compared with those reported for the gas and liquid-phase catalytic hydroge nation of m-xylene and explained through a model of molecular reorientation dependent on the electrode potential. (C) 2000 Elsevier Science Ltd. All r ights reserved.