Valorization of the Wheat Bran C5 Fraction Using Ru/ZrO2-MCM48 Catalysts

Monometallic Ru/MCM48 and Zr/MCM48 and bimetallic Ru/Zr-MCM48 and Zr/Ru-MCM48 catalysts have been synthesized and tested in the hydrogenation of wheat bran hydrolysates. Catalysts have been characterized by XRD, SAXS, TPR, TPD-NH3, TEM, and N2 adsorption/desorption at 77 K. The hemicellulose fraction has been extracted, hydrolyzed, and purified before the hydrogenation reaction. The purification step mainly consists of the extraction of the sugars in an organic phase and a back-extraction in an acid-aqueous solution. Ru/Zr-MCM48 catalyst exhibited the highest conversions of sugars in the hydrogenation of the purified wheat bran hydrolysate (PWBH), practically unchanged after 5 reaction cycles. Sugar alcohol yields were 73.2% in pentitols and 65.9% in sorbitol. The incorporation of the tetragonal ZrO2 to the MCM48 support has led to a more active and stable catalyst for the hydrogenation of PWBH. Results have shown that this incorporation must be done before the deposition of the Ru(0) phase.