Macroporous Niobium Phosphate-Supported Magnesia Catalysts for Isomerization of Glucose-to-Fructose

The catalytic performance of hierarchically porous niobium phosphate (NbP) supported magnesia for the glucose isomerization to fructose, was investigated under atmospheric air atmosphere. Porous NbP showed improved support effects on MgO in comparison to other metal oxides tested for glucose isomerization. Also, the amount and distribution of basic sites were largely changed by supporting magnesia on NbP. Although the textural properties were reduced and solid acids formed on the MgO/NbP catalysts, glucose isomerization was promoted by increasing magnesium content. The maximum yield of fructose reached similar to 24.6% over 40%MgO/NbP-500 with selectivity of 65.7% for 1.0 wt % glucose at 120 degrees C. The fructose productivity peaked as high as 13.6g g(catalyst)(-1) h(-1) over 40%MgO/NbP-700 catalyst. The leaching of cations and anions resulted in a homogeneous system for glucose isomerization. Regeneration almost fully reactivated the catalyst to its initial activity. The MgO/NbP showed high stability under air atmosphere for 15 days, and high potential use for glucose isomerization.