Electrocatalytic Hydrogenation of Diethyl Fumarate. A Simple System Development.

Article abstract of DOI:10.1016/S0040-4020(99)00385-3

Diethyl fumarate was chosen as a model in search for better conditions to achieve selective electrocatalytic hydrogenation. In addition to carbon felt, several catalytic cathode surfaces have been examined, including Fe, Pt, Ni, Pb, Al, Cu, Zn, and stainless steel. Other variables like current density (58 to 285 mA.dm²), supporting electrolyte (NaCl, KBr, NaBr, NaI, NaF), solution pH* (3.0 to 9.0) and co-solvent (CH3CN, t-BuOH, MeOH and THF) were tried. The majority of the reactions were carried out at constant current in an undivided cell fitted with the chosen working electrode and DSA (RuO2/TiO2) as the auxiliary electrode, in H2O/co-solvent (4:1). The best results for hydrogenation (84 percent chemical yield) were obtained using Fe as cathode, a current density of 175 mA.dm², in H2O/CH3CN (4:1) at pH* 5.5. NaBr and KBr are also useful electrolytes for hydrogenation. pH* variation does not seem to affect product ratio. THF as co-solvent and NaF as supporting electrolyte should be avoided, as well as carbon felt and Ni as electrodes.