Enhancing the reusability of hydroxyapatite by barium modification for efficient isomerization of glucose to fructose in ethanol

Abstract

The application of synthetic catalysts to displace costly isomerases for glucose isomerization to fructose has been a long-standing goal in biomass valorization, but current catalysts generally suffer from inferior stability and reusability. Here we show that the combination of barium modified hydroxyapatite (Ba/HAP) as catalyst with ethanol as solvent enables highly efficient and selective isomerization of glucose to fructose, affording fructose yield of 35.4% with selectivity up to 93.5% at high glucose loading (10 wt%). Moreover, the Ba/HAP catalyst was reused with high recovery rate and the leaching of ions was greatly inhibited. The composition, structure and catalytic activity of catalyst can be almost completely restored after calcination. Density functional theory simulations revealed that the formation of relatively stable BaCa6(PO4)4O phase is beneficial to the improved catalyst stability. Simultaneously achieving high reaction efficiency and good catalyst reusability in green solvent, our study is an important step towards sustainable catalysis.