Mutarotation of α-D-Glucose over Several Al2O3 Catalysts

Article abstract of DOI:10.1246/bcsj.60.4273

The mutarotation of α-D-glucose to β-D-glucose has been studied at 25 +/- 0.1 deg C using five kinds of alumina as catalysts.Two kinds of alumina with measurable surface basicities have exhibited high catalitic activities while the others with little surface basicities have exhibited low activities.Thus, the surface basic sites have been considered to be responsible for the catalytic activity observed.Any of crystal structures, surface areas, pore structures, and surface elemental compositions have no relation to the catalitic activity.It has also been revealed that the kinetics of the reaction is explained by a surface reaction mechanism where 1, K_α, K_β, k₁, and k₂ denote the active site, the adsorption equilibrium constant for β, the rate constant for the surface forward reaction, and the rate constant for the surface backward reaction, respectively, and the subscript ad denotes an adsorbed state.The result of kinetic analysis has revealed that K_β > K_α, indicating that the adsorption of β-glucose is stronger than that of α-glucose.This also supports the view that the surface basic sites are responsible for the catalytic activity.