One-pot aqueous-phase xylose upgrading on Zr-containing BEA zeolites

Xylose transformation into furfuryl alcohol was performed over modified BEA zeolites. BEA acidity was modified by incorporating Zr into zeolite by a post-synthesis procedure. HAlBEA showed to be selective towards furfuryl alcohol under reaction conditions used. Zr-containing zeolites were more active than the corresponding BEA catalysts but their efficiency to promote xylose conversion to furfuryl alcohol was related to Zr atoms incorporated in the framework. High Zr loadings generated isolated ZrO2 which promoted xylose isomerization to xylulose. It was associated with the depletion of Bronsted acid sites since presence of Bronsted and Lewis acid centres are crucial for the cascade process to furfuryl alcohol. ZrHAlBEA catalyst exhibited no significant deactivation upon four reaction cycles. Products distribution was not affected either, indicating that Bronsted and Lewis acid sites are preserved under the reaction conditions. Neither Al nor Zr were leached from the catalysts structure, corroborating their chemical stability in aqueous phase.