In addition, the yield of HMF is much closer to the conversion of fructose at lower reaction temperature. At the reaction temperature of 120.c, fructose conversion reached 98.5% after 2h, while the yield of HMF was 86.3%. The value gap betweem the fructose conversion and HMF yield indicated that some side reaction occurred during the dehydration of fructose over the Zr-P-Cr catalyst. No other chemicals were detected under our analytic conditions. According to the previous reports , the major side reactions are the condensation and polymerization of HMF into other undesired byproducts such as soluble polymers and insoluble humins. However, due to the unknown structure of the byproducts, it is difficult to identify in the present techniques, the formation of them can be verified through a change in the color of the reaction mixture from brown to black.