Au is a highly selective catalyst for the hydrogenation of alkadiene impurities without further hydrogenation of the alkene stream [1]. However, activity and stability of the Au catalyst are also important factors for industrial application. One option to increase the activity and stability of the catalyst is alloying of Au with a second metal. Ag has also shown activity and selectivity for the hydrogenation of unsaturated aldehydes such as acrolein to crotonaldehyde [2]. In this study, we investigated the activity, selectivity, and also the stability of monometallic Au and Ag as well as the Au-Ag bimetallic supported on SBA15 and Aerosil 300 for the selective hydrogenation of butadiene in an excess of propene. All the Au-based catalysts were selective toward hydrogenation of butadiene into butene, and at almost full conversion of butadiene, propane concentrations were lower than 300 ppm. Au/SBA15 reached close to 100% conversion at 200°C while propane concentration was less than 200 ppm. However, the Ag catalyst showed a low activity. The Au-Ag catalysts showed intermediate activities that decreased with increasing Ag loading, and deactivated over time at 200°C (Figure 1). We suggest that Ag segregation to the particle surface and/or coke formation is responsible for this deactivation. Surface studies to confirm or reject these hypotheses are in progress. The initial activity of the Au catalyst was independent of the type of silica support, but interestingly, Au/SBA15 was stable during more than 90 hours reaction at 200 °C, while Au/Aerosil showed slow deactivation (Figure 1). Studies involving other supports showed that the stability of Au depends strongly on the nature of the support.<br/>[1] Hugon, A., Delannoy, L., Krafft, J.M., Louis, C., J. Phys. Chem. C, 114 (2010) 10823.<br/>[2] Hohmeyer, J., Kondratenko, E.V., Bron, M., Kröhnert, J., Jentoft, F.C., Schlögl, R., Claus, P., J. Catal. 269 (2010) 5.

Au, Ag, and Au-Ag catalysts supported on SBA15 for the selective hydrogenation of butadiene

249th National Meeting (2015)

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