(205c) Vacancy-Mediated Hydrodeoxygenation of Furfuryl Alcohol over Metal Oxide

Authors: 
Goulas, K., University of Delaware
Jenness, G. R., University of Delaware
Mironenko, A. V., University of Delaware
Mazal, T., University of Delaware
Vlachos, D. G., University of Delaware
Hydrodeoxygenation (HDO) of biomass-derived molecules is a necessary step in their utilization as fuels or chemical intermediates. Processes in which high-pressure molecular hydrogen is used suffer from the disadvantages of cost and safety. Ru/RuOx/C materials can successfully catalyze the HDO of furfural [1] and HMF [2] in the presence of isopropanol, without the need for external hydrogen, as the alcohol acts as a hydrogen donor and solvent.

Theoretical (DFT and MKM) and experimental studies of this system show that the HDO of furfural to methylfuran (MF) proceeds via a Meerwein-Ponndorf-Verley transfer hydrogen transfer from isopropanol to furfural [3]. The furfuryl alcohol produced in this step is subsequently deoxygenated over an oxygen vacancy on the RuO2 surface [4]. Vacancies on the RuO2 surface form by the reaction of H2 produced from the dehydrogenation of isopropanol on the Ru surface with surface O atoms of RuO2. However, nucleation of the vacancies causes the complete reduction of RuO2, resulting in the suppression of the HDO reaction and poor recyclability of the catalyst [2]. As such, the discovery of a stable catalyst is of great importance for the viability of this process.

In this work, we generalize and extend our conclusions to different oxides and metals that have been reported in the literature as active for HDO reactions, such as MoO3 [5] and Pt [6]. We combine experimental measurements of the HDO rate over a range of oxides in a batch reactor with a theoretical investigation of oxygenated species on these materials. These investigations yield an excellent correlation of the rate of HDO with intrinsic properties of the materials. Based on these investigations, we are able to propose and successfully employ a rationally-designed active and stable catalyst system for the HDO of furfural to MF.

References:

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

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

3. Gilkey, et al. ACS Catal. 5 (2015) 3988-3994

4. Mironenko and Vlachos. J. Am. Chem. Soc. (2016) Accepted

5. Prasomsri, et al. Energy Environ. Sci., 6 (2013) 1732-1738

6. Luo, et al. Catal. Lett. 146 (2016) 711-717

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