Selective Catalytic Dehydration of Xylose to Furfural and Fructose and Glucose to 5-Hydroximethylfurfural (HMF) Using Preyssler Heteropolyacid

Catalytic dehydration of xylose to yield furfural was studied by testing different heteropolyacid-type catalysts. Preyssler heteropolyacid (HPA-Preyssler) (H-14[NaP5W30O110]) was the most efficient. Under the optimal reaction conditions, xylose was dehydrated into furfural with 73% of yield and 95% of selectivity using DMSO as solvent at 140 degrees C for 4 h. The HPA-Preyssler catalyst also exhibited good catalytic activity in the dehydration of fructose and glucose to yield 5-hydroxymethylfurfural (HMF). Thus, from fructose a yield and selectivity to HMF of 97% and 98%, respectively, was obtained in just 10 min, while from glucose, 91% of conversion and 23% of yield were obtained after 9 h. An easy and efficient methodology for the recovery and reuse of HPA-Preyssler in at least six reaction cycles without appreciable loss of its initial catalytic activity is reported.