Synergism studies on alumina-supported copper-nickel catalysts towards furfural and 5-hydroxymethylfurfural hydrogenation

• Published in: Journal of molecular catalysis. A, Chemical Vol. 426; pp. 244 - 256
• Main Authors: Srivastava, Sanjay, Jadeja, G.C., Parikh, Jigisha
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2017
• Subjects: 2,5-Dimethylfuran; 2-Methylfuran; 5-Hydromethylfurfural; Cu-Ni; Furfural; Cu-Ni; 5-Hydromethylfurfural; 2,5-Dimethylfuran; Furfural; 2-Methylfuran
• ISSN: 1381-1169; 1873-314X
• DOI: 10.1016/j.molcata.2016.11.023

[Display omitted] Present contribution focuses on the structural and performance studies on alumina-supported copper-nickel catalysts for hydrogenation of furfural and 5-hydroxymethylfurfural towards 2-methylfuran and 2, 5-dimethylfuran which are used as biofuels additives. •Synergy between Cu and Ni results in highly dispersed Cu particles on to alumina surface.•Cr-free, noble metal free bimetallic alumina supported Cu-Ni catalysts are found to be active for hydrogenation of both FAL and HMF.•Temperature played a significant role in driving the selectivity towards 2-MF and DMF via hydrogenolysis. The structure of alumina-supported copper-nickel catalysts prepared by impregnation method was studied by using a combination of various characterization techniques including XRD, N2-sorption, TEM, H2-TPR, NH3-TPD, XANES/EXAFS and CHNS methods. A series of characterizations revealed that dispersion of copper increases with an increase in nickel loading on ɣ-Al2O3 due to strong interaction between nickel and copper oxide particles. This also led to the formation of mixed copper-nickel oxides in calcined catalysts at the highest loading of nickel and copper (i.e. Cu/Ni=1). In catalytic activity, both the monometallic Cu/ɣ-Al2O3 and Ni/ɣ-Al2O3 showed lower activity and selectivity towards hydrogenation of both Furfural and 5-Hydroxymethylfurfural to 2-methylfuran (2-MF) and 2, 5-dimethylfuran (DMF), respectively. However, with increase in nickel loading, the activity and the selectivity of Cu/ɣ-Al2O3 drastically increased for both the cases and Cu-Ni/ɣ-Al2O3 (Cu/Ni=1) showed the highest catalytic activity. Furthermore, combination of Cu/Ni ratios and temperature plays a significant role in the product distribution, as in the case of furfural hydrogenation, at a lower temperature, furfuryl alcohol (FOL) appears as the main product while at a higher temperature, 2-methylfuran (2-MF) is found to be the dominant product over Cu-Ni/ɣ-Al2O3 (Cu/Ni=1) catalysts. Similarly, 2,5-bishydroxymethylfuran (BHF) is found to be the major product at a lower temperature and 2,5-dimethylfuran (DMF) is selectively produced at a higher temperature in the HMF hydrogenation. Furthermore, reaction pathways are discussed for both the reactions.