The dehydration of sugars (fructose, glucose, and xylose) was studied using different resins and silicas functionalized with sulfonic as catalysts and a mixture of acetone/water 80:20 as the solvent in a flow system. The reaction conditions (temperature, sugar concentration, and residence time) were studied. The high concentrations of acetone in the solvent favor selectivity for furan compounds but difficult the solubility of the sugars The activity tests revealed different behaviors between acid catalysts employed, catalysts based on resins are more active, but the intrinsic activity (TOF) of silica-based catalysts are higher, these behavior are related with the amount of sulfonic groups and surface nature of the catalysts respectively. A life study (more than 100 h) of selected catalysts was carried out showing that the resin-based catalysts are pretty stable, but the silica counterpart deactivates by leaching of the organic groups that contain the sulfonic groups. The studied flow process that combines a heterogenous catalyst and acetone/water solvent is a very promising candidate to be scaled up to an industrial scale.