Utilization of gamma-radiation in the synthesis of bimetallic Cu-Ni catalysts for selective vapour phase hydrogenation of levulinic acid to gamma-valerolactone

A set of mono and bimetallic Cu-Ni systems supported on gamma-alumina catalysts were synthesized using gamma-radiation instead of conventional calcination and reduction. Using a variety of characterization approaches, the structural and surface characteristics of catalysts were determined and their properties were compared with their counterparts prepared using the conventional method. The efficiency of these catalysts for the vapour phase selective hydrogenation of levulinic acid (LA) to gamma-valerolactone (GVL) was investigated. The catalysts prepared by gamma-irradiation contain Cu in its metallic state with high dispersion. gamma-Radiation is advantageous because it enables the preparation of metal-supported catalysts in a single step by avoiding post-reduction. The catalysts prepared by gamma-irradiation presented a higher activity compared to the conventional catalysts. Among all, the catalysts with 10%Cu-7%Ni on gamma-Al2O3 demonstrated the highest conversion (94.5%) and selectivity (97%). The enhanced activity of the gamma-irradiated catalysts was mostly attributable to the existence of a high surface area and copper dispersion. The gamma-irradiated catalyst showed stable activity during the time of stream analysis. The desired reaction conditions to achieve a high yield of gamma-valerolactone were also optimized.