Isomerization of D-glucose (Glc) into D-fructose (Fru) presents an important step in the catalytic valorization of cellulosic biomass. However, a rational catalyst design for isomerization poses a challenge. In this work, we studied the catalytic activity of basic salts with low solubility Li 2 CO 3 , MgCO 3 , Li 3 PO 4 , SrCO 3 , CaCO 3 , BaCO 3 , and Mg 3 (PO 4 ) 2 for Glc isomerization into Fru. In bulk water, these materials generate OH − via partial dissolution and protonation of the

more »

... . The catalysts were tested for isomerization using 10 wt% aqueous Glc solution at 60 and 80 °C. The initial rate of Fru formation r 0,Fru shows an excellent correlation with the initial pH values of the reaction mixtures, indicating in situ generated OH − anions as catalytically active species. Filtration and contact tests were performed and their limited applicability for catalysis by bases with low solubility was shown. Li 2 CO 3 showed the highest catalytic activity for the isomerization, resulting in 25% Fru yield in 10 minutes at 80 °C. The selectivity of the isomerization depends on the catalyst nature. The highest selectivity for Fru formation was observed in the presence of MgCO 3 , giving rise to 27% Fru yield at 80 °C. MgCO 3 and MgO could be recycled without loss of activity.