Fast furfural formation from xylose using solid acid catalysts assisted by a microwave reactor

The production of furfural (FUR) from xylose was carried out using sulfated zirconia (SZ) on cordierite, alumina on cordierite and commercially-available polymeric solid catalysts (Amberlyst DT and Nafion NR40) to provide insights into the reaction pathways and kinetics for the dehydration of xylose in aqueous phase. Experiments conducted at three temperatures were investigated (170, 190 and 210 °C) in a stirred microwave-assisted batch reactor, which established the optimal conditions to obtain the highest FUR yield as well as extensive and fast xylose conversion. The maximum FUR yields obtained from xylose were 41 mol% when using SZ on cordierite in 2 min (at 210 °C), 43 mol% when using alumina on cordierite in 30 min (at 210 °C) and 48 mol% for an auto-catalyzed system in 60 min (at 210 °C). Based on the experimental results, a reaction mechanism was proposed considering the formation of an intermediate from xylose when solid acid catalysts were added. After five reusability cycles using SZ on cordierite, this catalyst can be regenerated with a similar performance and similar FUR yield on the 6th cycle.