Hydrogenation of citral over nitrogen‐doped carbon nanofibre‐supported nickel catalyst

Abstract

AbstractHerringbone carbon nanofibres (hCNFs) and nitrogen‐doped carbon nanofibres with 0.115 g/g (11.5 %) of N (N‐hCNFs) were used as the supports of nickel catalysts in the liquid phase hydrogenation of citral using toluene as a solvent. Over 96 % selectivity to citronellal was obtained at 150 °C for both catalysts. At the reaction temperature of 200 °C, reasonable amounts of isopulegol were formed additionally as a result of citronellal cyclization. The catalytic activity of Ni nanoparticles was significantly improved when supported on CNFs doped with nitrogen. The hydrogenation of cis‐citral was remarkably favoured over the trans‐citral isomer regardless of the reaction temperature. The hydrogenation of citronellal under the same process conditions was also studied. The sequential‐parallel reactions network for the hydrogenation of citral under the applied conditions was proposed and the kinetic constants were evaluated, assuming pseudo‐first order kinetics of the hydrogenation process.