A process to produce furandicarboxylic acid (FDCA). The process includes the steps of reacting a C6 sugar-containing reactant in a reaction solution comprising a first organic solvent selected from the group consisting of beta-, gamma-, and delta-lactones, hydrofurans, hydropyrans, and combinations thereof, in the presence of an acid catalyst for a time and under conditions wherein at least a portion of the C6 sugar present in the reactant is converted to 5-(hydroxymethyl)furfural (HMF); oxidizing the HMF into FDCA with or without separating the HMF from the reaction solution; and extracting the FDCA by adding an aprotic organic solvent having a dipole moment of about 1.0 D or less to the reaction solution.