The disclosure relates to a method for forming 2,5-furan dicarboxylic acid (FDCA) from aldaric acids. The aldaric acids are dehydrating and cyclizing via acid catalysis to form the FDCA product. Aldaric acids such as galactaric acid, gularic acid, mannaric acid, and glucaric acid can be used in the disclosed method, and the aldaric acids can be obtained from form renewable biomass sources which contain pectin, alginate, and/or other biomass carbohydrates. The FDCA can be used as a renewable feedstock for consumer product polymeric materials such as polyalkylene furoate polymers.