Efficient production of furfural from xylose and wheat straw by bifunctional chromium phosphate catalyst in biphasic systems

We present here a study of the production of furfural from xylose and wheat straw using the chromium phosphate (CrPO₄) with Lewis and Brønsted acidity as a highly efficient catalyst in the water/tetrahydrofuran (THF) biphasic system. The effects of various reaction parameters including reaction temperature, reaction time, system, and catalyst dosage were explored to evaluate the product yield. Under CrPO₄ catalysis, an excellent furfural yield could reach 88% from the xylose at 160 °C for 60 min. Meanwhile, 67% furfural and 32% 5‑hydroxymethylfurfura (HMF) were simultaneously achieved from wheat straw at 180 °C for 90 min. Mechanistic studies suggested that the perfect catalytic activity of CrPO₄ was due to its inherent bifunctional catalysis activity. It was found that the CrPO₄ was easily to be recovered and a great catalytic activity was available after four cycles, which not only contributed to a sustainably reduced energy consumption on catalyst recovery, but also reduced the concerns associated with toxic chromium element.