(535b) Reaction Condition Optimization for the Scalability of 1,4-Anhydroerythritol and Xylitol Conversion Via Heterogeneous ReOx-Pd/CeO2 Catalysis

Some biomass is rich in sugars that contain hydroxyl groups, which can either undergo deoxydehydration to form double bonds or hydrodeoxygenation (HDO) to remove vicinal hydroxyl groups. HDO via deoxydehydration followed by a hydrogenation step allows for the simultaneous removal of multiple vicinal hydroxyl groups¹. Literature has shown that ReOx-Pd/CeO₂ is a better catalyst for the simultaneous HDO of 1,4-anhydroerythritol as compared to ReOx-Pd on other oxide supports². The simultaneous HDO of 1,4-anhydroerythritol, which produces tetrahydrofuran, was used as a model reaction for HDO. Pressure and temperature effects on the system will be explored through a design of experiment in order to elucidate scalable conditions for HDO reactions. Xylitol is another biomass derived chemical that can be upgraded to value-added products through simultaneous HDO, but there is a lack of understanding on how ReOx-Pd/CeO₂ catalysts perform for this reaction². Thus reaction condition optimization could benefit this process significantly. In order to obtain a detailed understanding of the optimal conditions for these reactions, a design of experiment was enacted to discern the effects and interactions of temperature, pressure, and catalyst loading. Xylitol was chosen as a reactant to compare to the model 1,4-anhydroerithritol reaction due to it having three vicinal cis-hydroxyl groups and in order to form 1,2,5-pentanetriol and other products by selectively removing hydroxyl groups. The xylitol HDO has been conducted in literature at 80bar and 443K². Reducing the pressure would allow for this process to become more economically favorable and scalable. The findings from the 1,4-anhydroerythritol reaction design of experiments were extended to the xylitol reaction in order to find trends between the operating conditions, resulting in more reasonable operating conditions.

References

(1) Ota, N.; Tamura, M.; Nakagawa, Y.; Okumura, K.; Tomishige, K. Performance, Structure, and Mechanism of ReO _x –Pd/CeO ₂ Catalyst for Simultaneous Removal of Vicinal OH Groups with H ₂. ACS Catal. 2016, 6 (5), 3213–3226.

(2) Ota, N.; Tamura, M.; Nakagawa, Y.; Okumura, K.; Tomishige, K. Hydrodeoxygenation of Vicinal OH Groups over Heterogeneous Rhenium Catalyst Promoted by Palladium and Ceria Support. Angew. Chemie - Int. Ed. 2015, 54 (6), 1897–1900.