Aqueous phase dehydration of glucose with supported phosphate catalysts

Abstract

Consulta en la Biblioteca ETSI Industriales (8833)

[EN] A series of well characterized solid phosphate catalysts have been prepared for the two steps dehydration/hydrolysis reaction of glucose into levulinic acid. The catalysts include three zirconium phosphates and two tin phosphates with different ratios metal/phosphorous characterized by Elemental Analysis. The total amount of acid sites and the concentration of Brønsted and Lewis sites in these catalysts have been characterized with TPD and FT-IR techniques respectively using gas phase NH3. The chemical structure and the surface area have been also determined with XRD and BET techniques. The results obtained for the catalytic activity and selectivity have been compared with that of homogeneous catalysts, including HCl as a Brønsted acid and Yb(OTf)3 as a Lewis acid. The catalyst selectivity is a function of the Brønsted to Lewis acid site ratio for both the heterogeneous and homogeneous reactions. Brønsted acid sites increase levulinic acid selectivity while Lewis acid sites increase catalytic activity but lead to a higher formation of degradation products also called humins. The isomerization reaction of glucose into fructose is catalyzed by Lewis acid sites