Purified Terephthalic Acid (PTA) is used to manufacture polyester coatings resins for use in the formulation of general metal, appliance, automotive, industrial maintenance, and coil coatings. The primary application for PTA is in combination with NPG in polyester powder coating resins. Terephthalic acid is an important raw material for the production of polyethylene terephthalate (PET). It is usually obtained by the catalytic oxidation of p-xylene in air, in the presence of acetic acid (HAc) as solvent. Modern technologies produce purified terephthalic acid by the catalytic liquid phase oxidation of paraxylene in acetic acid, in the presence of air. The process uses manganese or cobalt acetate as a catalyst. The reaction is exothermic, producing water which is removed in a solvent recovery system.