Hydrolysis of Cellobiose and Xylan over TiO2-Based Catalysts

Hydrolysis of hemicelluloses is a key step in biorefineries processes. In this paper, TiO2-based catalysts were prepared and applied to the hydrolysis of a model compound, cellobiose, and then to xylan from corncob. Hydrolysis of cellobiose yielded glucose (60%), hydroxy-methylfurfural (HMF) and humins in various amounts depending on the catalyst nature. Activity and selectivity to glucose varied with the nature of dopant (W or Zr) and the calcination temperature of the catalyst. A kinetic model was built to elucidate the formation of humins and showed that the direct pathway "cellobiose to humins" is predominant in our reaction conditions. TiO2–W catalyst was then applied to xylan hydrolysis. Xylan reacted much faster than cellobiose and yielded xylose and furfural with low humins production.