No abstract

No abstract

One-pot production of furfuryl alcohol via xylose dehydration followed by furfural hydrogenation was investigated over a dual catalyst system composed of Pt/SiO 2 and sulfated ZrO 2 as metal and acid catalysts, respectively. All samples were characterized by XRD, XRF, N 2 physisorption, TG-MS and FTIR regarding their most fundamental properties for the studied process. A systematic study is reported on the effects of the reaction temperature, the composition of the binary solvent and the molar ratio between acid and metal sites in the catalyst system. The results revealed the feasibility of the one-step process for furfuryl alcohol synthesis and showed that the occurrence of both acid and metal sites is compulsory in order to promote the dehydration of xylose to furfural and its further hydrogenation to furfuryl alcohol. Selectivity towards furfuryl alcohol was found to be strongly dependent on the solvent, which can inhibit its polymerization to some extent. † Electronic supplementary information (ESI) available. See

No abstract

The Cannizzaro reaction of pyruvaldehyde to lactic acid is investigated in a flow reactor with ZrO2 catalysts with different structures and acid–base properties. The results show that a difference in the crystalline structures of two ZrO2 polymorphs strongly affects the conversion of pyruvaldehyde. The monoclinic phase of zirconia is the most active for this reaction. A good correlation is observed between the reaction rate and the concentration of Lewis acid sites of sufficient strength, which shows that these sites play a major role in the reaction. A reaction mechanism is proposed involving coordinatively unsaturated Zr4+ cations as sites for activating pyruvaldehyde molecules, whereas Zr4+−O2− pairs generate terminal OH groups through water dissociation.