One of the most important commercials industrial processes is liquid phase catalytic oxidation of p-xylene by oxygen for terephthalic acid (TPA) production. A recent catalytic system used environmentally benign N-hydroxyamide as a free radical promoter rather than more hazardous bromine molecules. An economical and easily prepared heterogeneous oxidation catalyst, nanorods manganese dioxide, was synthesized by ultrasonic technique. The crystal structure and morphology of the MnO₂ were confirmed by HRTEM, XRD, and N₂-adsorption-desorption isotherms. The prepared MnO₂ nanorods had a high aspect ratio and surface area of 300 m² g^-1.  The catalytic oxidation of p-toluic acid (PTA) to terephthalic acid using MnO₂ nanorods was studied under the different conditions (reaction time, catalyst dosages, reaction solvent and varied pressures and temperatures) to control the yield and selectivity toward TPA synthesis.  The obtained results showed that the high yield (88.9%) and conversion (90.1%) in ethyl acetate with fixed oxygen pressure (20 atm) at 150°C.