Fast production of furfural from xylose using solid acid catalysts

In recent years we have witnessed much activity to upgrade sugars contained in side-streams from the pulp and paper industry into ethanol and other value-added chemicals. An interesting catalytic route, namely the dehydration of sugars to furans, is considered one of the most promising routes for the production of platform chemicals and fuels. Furans such as furfural are highlighted in the “Top 10 + 4” by the United States Department of Energy list as the most rewarding bio-based platform molecules (1). The current furfural production uses mineral acids at approx. 200 °C, providing around 50 mol% yield. These mineral acids possess several drawbacks, e.g., high toxicity, corrosiveness, difficult recovery and large salt waste after work-up. The purpose of this study is to replace the mineral acid with solid acid catalysts. This approach may offer several advantages over current processes in the conversion of pentosan derivatives e.g. xylose into furfural: high yields, facile separation and reusability of the catalyst. In the present study, we aimed to combine the efficiency of microwave-assisted reactor and the use of solid acid catalysts for the dehydration of xylose to produce furfural in short times. Different solid acid catalysts were developed for this purpose (sulfated zirconia and alumina on cordierite), due to their high stability and acid capacities (2) required for a satisfactory performance under these conditions. The results of this work could be used to produce platform chemicals from sugar-based side-streams in the forestry industry, in particular from the pre-hydrolysate liquor generated during dissolving pulp production. These obtained value-added products have applications in a wide range of industrial branches (biofuel, pharmaceutical, agrochemical, petrochemical and chemical industry, among others).