Conversion of glucose over SO42-/ZrO2-TiO2 catalysts in an extremely low acid system

SO42-/ZrO2-TiO2 catalysts prepared by precipitation and impregnation methods were employed for glucose conversion. The basic structures of the prepared catalysts were characterized by XRD, BET, NH3-TPD, XPS, and TEM techniques. The essential properties of SO42-/ZrO2 could be improved greatly by adding a suitable amount of TiO2. High BET area and pore volume favored glucose conversion. The conversion rate of glucose into levulinic acid catalyzed by SO42-/ZrO2-TiO2 increased significantly in an extremely low acid system, indicating that the acidic condition was favorable for levulinic acid formation. The combined yield of 5-hydroxymethylfurfural and levulinic acid reached 28.8% with the presence of SO42-/ZrO2-TiO2 when the Zr-Ti molar ratio was 5:5 at 170°C for 2 h in the extremely low acid system. Studies on catalyst recycling were also further investigated in this study.