(270c) Hydrodeoxygenation of Furfural over Multifunctional Catalysts

Authors: 
Goulas, K. A., University of Delaware
Vlachos, D. G., University of Delaware
Mironenko, A. V., University of Delaware
Jenness, G. R., University of Delaware
Vorotnikov, V., University of Delaware
Mazal, T., University of Delaware
Hydrodeoxygenation (HDO) of biomass-derived platform molecules, such as furfural and hydroxymethylfurfural (HMF) is required for their utilization as fuels or chemical precursors. In our previous work [1,2], we have shown the utility of trifunctional Ru/RuOx catalysts for the HDO of furfural and HMF. Based on theoretical and experimental studies, we have shown that these reactions require the presence of a metal and an oxide and proceed through a Lewis-acid-mediated transfer hydrogenation from isopropanol to furfural over the RuO2, followed by the deoxygenation of furfuryl alcohol over O vacancies on the RuO2 surface. These vacancies are generated in the reaction of surface oxygen with hydrogen produced in situ from the dehydrogenation of isopropanol over the metal sites [3].

However, the 2-methylfuran (2MF) product may further react over Ru, giving undesirable 2-methyltetrahydrofuran (MTHF) and 2-pentanol, and consuming valuable hydrogen [4]. Moreover, RuO2 is reduced to metallic Ru under reaction conditions, resulting in the suppression of the HDO reaction. For these reasons, we have developed an alternative catalyst for the HDO of furfural to 2MF. To do this, we correlate the intrinsic HDO rates and the catalyst stability over a series of oxides with bulk and surface DFT descriptors and we choose an active and stable oxide. Extensive catalyst characterization, including microscopy, XPS, XRD, and XAS, is conducted. In a parallel effort, we correlate the selectivity of monometallic and bimetallic catalysts with the descriptors using correlations for thermochemistry and kinetics, such as group additivity and Polanyi relations. These studies demonstrate volcano like behavior and reveal best materials for HDO of biomass molecules.

References:

1. Panagiotopoulou, Vlachos. Appl. Catal A: General, 480 (2014) 17-24

2. Jae, et al. ChemCatChem, 6 (2014) 848-856

3. Mironenko and Vlachos. J. Am. Chem. Soc. (2016) 2016, 138, 8104–8113

4. Gilkey, et al. (2016) ChemSusChem, 9, 3113-3121