Hydrogen-free hydrogenation of furfural to furfuryl alcohol and 2-methyl-furan over Ni and Co-promoted Cu/γ-Al2O3 catalysts

Catalytic transformation of furfural to furfuryl alcohol and 2-methylfuran without H-2 supply toward transfer hydrogenation process using 2-propanol as a H-2 source was systematically investigated over the bimetallic NiCuAl and CoCuAl catalysts in comparison with the monometallic CuAl, NiAl, and CoAl catalysts. The XRD analysis confirmed the generation of Ni-Cu and Co-Cu alloys after the reduction in presence of H-2. The interaction between Cu and Ni or Co resulted in a simplicity of the reduction behavior of Ni and Co species observed in H-2-TPR experiments. It was evident from pyridine adsorption FTIR analysis that the formation of bimetallic NiCu and Co-Cu alloys apparently improved the stronger Lewis acidic sites. The influences of reaction temperature and time were examined and optimized to maximize the yields of furfuryl alcohol and 2-methylfuran. The highest two major products yield and selectivity with lower by-products were obtained over the NiCuAl and CoCuAl catalysts compared with the CuAl and NiAl catalysts. The superior performance of the bimetallic catalysts was attributed to the stronger Lewis acidic centre on the catalyst surface. The CoCuAl catalyst was found to have lower catalyst deactivation and carbon deposition among the CuAl and NiCuAl catalysts under H-2-free atmosphere.

Automated summary

This study systematically investigated the catalytic transformation of furfural to furfuryl alcohol and 2-methylfuran without the need for hydrogen supply using bimetallic NiCuAl and CoCuAl catalysts. The bimetallic catalysts showed higher yields and selectivity compared to monometallic CuAl and NiAl catalysts, attributed to the stronger Lewis acidic centers on their surfaces. Additionally, the CoCuAl catalyst exhibited lower catalyst deactivation and carbon deposition under an H-2-free atmosphere.