Production of furfural from xylose and hemicelluloses using tin-loaded sulfonated diatomite as solid acid catalyst in biphasic system

Aiming to develop an ecologically and economically viable catalytic pathway, dehydration of D-xylose and hemicelluloses to furfural was performed using tin-loaded sulfonated diatomite (SO42−/Sn-DM) as solid acid catalyst in mild reaction system. The solid acid was characterized by SEM, EDS, XRD, ICP, py-IR and NH3-TPD. Results indicated the solid acid was rich in Lewis and Brønsted acidities that mainly contain Sn4+ and sulfonic group respectively, which was distributing uniformly on the surface of modified DM. Compared with the pure water solution, furfural catalyzed in saturated NaCl aqueous-toluene biphasic system showed better performance. The effect of solvent assistant, time and temperature of the catalytic process were optimized. A maximized furfural yield of 80.97% and 84.39% were obtained using xylose and water-soluble hemicelluloses as the substrate respectively. The solid acid catalyst also showed good stability after 5 cycles.