The highly efficient synthesis of 5-hydroxymethylfurfural (HMF) from carbohydrates was achieved using the inexpensive and bi-functional CrPO4 catalyst in a biphasic system. The effect of various reaction conditions, including reaction temperature, time, and solvent, on HMF yields was explored. A HMF yield of up to 83% was obtained using fructose as the reactant at 140 °C for 15 min. A maximum HMF yield of 63% was also achieved from glucose when the reaction was carried out at 140 °C for 30 min. Among the reported catalysts, CrPO4 was shown to be one of the most effective in the conversion of glucose into HMF, which is comparable to an ionic liquid reaction system. Moreover, the CrPO4 catalyst exhibited high activity to convert microcrystalline and lignocellulosic feedstock to HMF without the need for the addition of homogeneous mineral acids. The possible conversion mechanism of carbohydrates into HMF catalyzed by the bi-functional CrPO4 catalyst is discussed.
