Preparation of zirconium carbonate as water-tolerant solid base catalyst for glucose isomerization and one-pot synthesis of levulinic acid with solid acid catalyst

In this research, zirconium compounds were prepared as water-tolerant solid base catalysts by a simple method. Their catalytic activities were investigated in the aqueous glucose-fructose isomerization reaction. The zirconium carbonate (ZrC) catalyst could work in wide range of reaction temperature (80-140 A degrees C) and the maximum glucose conversion reached 45 % at 120 A degrees C with 76 % selectivity to fructose. The ZrC catalyst was found to retain its activity without significant decrease in the fructose yield after being used for five times. In the one-pot transformation of glucose to levulinic acid (LA), the ZrC could afford 17 % yield of LA after 12 h reaction in water-toluene biphasic solvents in combination with a solid acid catalyst, Amberlyst-15. The proposed reaction system in water-toluene biphasic solvents occurred faster and gave higher LA yield than that in pure water solvent.