(112e) Selective Hydrogenation of Acetic Acid to Ethanol On Ru Surfaces

Hydrogenation of organic acids is an important step in the conversion and upgrading of biomass-derived feedstock for the production of valuable liquid fuels and chemical intermediates. Supported Ru catalysts have been shown to selectively hydrogenate organic acids into the corresponding alcohols or aldehydes in several aqueous-phase experiments [1-4] but to completely break down acetic acid in gas phase or vacuum.[4,5] To shed light on the mechanistic underpinnings of this phenomenon, self-consistent periodic density functional theory calculations have been performed to investigate the hydrogenation of acetic acid, one of the simplest carboxylic acids, to ethanol on Ru surfaces. Several selective hydrogenation pathways and non-selective decomposition pathways are explored, and the basic features of the activation of acetic acid and some of the factors that control the selectivity to ethanol are identified. Our results provide fundamental insight for the challenging task of developing new catalysts for efficient biomass feedstock processing.

(1) Varadarajan, S.; Miller, D. J. Biotechnol. Prog. 1999, 15, 845.

(2) Chen, Y. Q.; Miller, D. J.; Jackson, J. E. Ind. Eng. Chem. Res. 2007, 46, 3334.

(3) Dalavoy, T. S.; Jackson, J. E.; Swain, G. M.; Miller, D. J.; Li, J.; Lipkowski, J. J. Catal. 2007, 246, 15.

(4) Olcay, H.; Xu, Y.; Huber, G. W. submitted.

(5) Garcia, A. R.; da Silva, J. L.; Ilharco, L. M. Surf. Sci. 1998, 415, 183.