Abstract |
The isomerization of aldo-saccharides to keto-saccharides is an important transformation in biomass conversion processes. The use of eco-friendly heterogeneous catalysts for these reactions is most attractive, albeit good catalytic stability continues a challenge. The as-synthesized Aveiro-Manchester material number 4 (AM-4, Na-3(Na,H)Ti2O2[Si2O6](2),2H(2)O) possessed isomerization activity, but limited stability. This versatile precursor material was modified to meet superior performances in the base-catalyzed isomerization of the monosaccharides d-glucose and d-xylose, and the disaccharide d-cellobiose, at 100 degrees C. Different alkali and alkaline-earth metals were introduced into AM-4, which influenced the catalytic properties. The Mg-containing material was the most stable, leading to 27 \% fructose yield from d-glucose, 41 \% cellobiulose from d-cellobiose and 39 \% xylulose from d-xylose isomerization, at 2 h reaction. |