Attapulgite as natural catalyst for glucose isomerization to fructose in water

Fructose is generated from glucose isomerization in water over attapulgite without any addition of metal compounds. The formation of fructose was related closely to the calcination processing of attapulgite. The highest fructose yield of 20.6% was obtained with the selectivity of 77.9% over attapulgite calcined at 500   °C. Moreover, attapulgite was characterized by BET, XRD, IR and CO 2 -TPD techniques. The results indicated that proper distribution and amount of basic sites were crucial for the selectivity of fructose as well as the structural properties of attapulgite.