Terephthalic acid is prepared by reacting a 2,5-furandicarboxylate with ethylene in the presence of a solvent to produce a bicyclic ether; and then dehydrating the bicyclic ether. The process of the present invention effectively produces terephthalic acid, while reducing or eliminating the impurities, color bodies and carbon oxides produced in commercial practice by the liquid-phase oxidation of methyl-substituted benzene feedstocks.