Scrap waste automotive converters as efficient catalysts for the continuous-flow hydrogenations of biomass derived chemicals†
The catalytic activity of scrap ceramic-cores of automotive catalytic converters (SCATs) was investigated in the continuous-flow hydrogenation of different biomass-derived chemicals. The waste SCAT powders were deeply characterized by ICP-MS, TGA, MP-AES, XRD, N2 physisorption, TPR, HRTEM and EDS before and after utilization as a catalyst. The hydrogenation reactions of isopulegol to menthol, cinnamyl alcohol to hydrocinnamyl alcohol, isoeugenol to dihydroeugenol, vanillin to vanillyl alcohol and benzaldehyde to benzyl alcohol were performed studying the influence of various reaction parameters (temperature, pressure, flow rate and concentration of the starting material) on the final yields. The outstanding performance and stability obtained for the low metal content of waste-derived catalysts can be attributed to the co-presence of different noble metals as well as to the composite structure itself.