A closed-loop process for converting biomass into furfural, the process comprising the steps of: (a) providing a pentosan-containing biomass material; (b) subjecting the pentosan-containing biomass material to an acid catalyzed digestion process in a digestion vessel at a temperature greater than 100 °C for a period of time sufficient to produce a digested product stream comprising C 5 -carbohydrates and solids comprising cellulose; (c) separating the digested product stream into a liquid product stream and a solid product stream, the liquid product stream comprising carbohydrate compounds, of which carbohydrate compounds at least 50wt% are C 5 - carbohydrate compounds, based on the weight of carbohydrate compounds in the liquid product stream, and the solid product stream comprising solids comprising cellulose; (d) subjecting the C 5 -carbohydrate in the liquid product stream to a dehydration reaction in a reaction vessel at a temperature in the range of from 100 °C to 250 °C in the presence of an acid catalyst and a biphasic mixture comprising an aqueous phase and a water-immiscible organic phase, which comprises an organic solvent, for a period of time sufficient to produce furfural or a furan derivative; (e) retrieving from the reaction vessel a dehydration product stream comprising water, organic solvent and comprising furfural and separating the dehydration product stream into an aqueous recycle stream and an organic product stream comprising furfural; (f) recycling the aqueous recycle stream back into the digestion vessel in step (b); and (g) extracting the furfural from the organic product stream by at least one separation process. (a) providing a pentosan-containing biomass material; (b) subjecting the pentosan-containing biomass material to an acid catalyzed digestion process in a digestion vessel at a temperature greater than 100 °C for a period of time sufficient to produce a digested product stream comprising C 5 -carbohydrates and solids comprising cellulose; (c) separating the digested product stream into a liquid product stream and a solid product stream, the liquid product stream comprising carbohydrate compounds, of which carbohydrate compounds at least 50wt% are C 5 - carbohydrate compounds, based on the weight of carbohydrate compounds in the liquid product stream, and the solid product stream comprising solids comprising cellulose; (d) subjecting the C 5 -carbohydrate in the liquid product stream to a dehydration reaction in a reaction vessel at a temperature in the range of from 100 °C to 250 °C in the presence of an acid catalyst and a biphasic mixture comprising an aqueous phase and a water-immiscible organic phase, which comprises an organic solvent, for a period of time sufficient to produce furfural or a furan derivative; (e) retrieving from the reaction vessel a dehydration product stream comprising water, organic solvent and comprising furfural and separating the dehydration product stream into an aqueous recycle stream and an organic product stream comprising furfural; (f) recycling the aqueous recycle stream back into the digestion vessel in step (b); and (g) extracting the furfural from the organic product stream by at least one separation process.