Terephthalic acid paraxylene oxidation

Terephthalic acid is an important monomer for producing polyesters. The main route for obtaining the acid is the catalyzed oxidation of paraxylene. It can also be produced from benzoic acid by a disproportionation reaction of potassium benzoate in the presence of carbon dioxide. Benzene is the coproduct ... 

S.13i. Terephthalic acid (TPA) is produced by air oxidation of paraxylene at 200 psig. The reaction is exothermic. Nitrogen plus excess oxygen leave the top of the reactor. 

Mitsui Chemicals, Inc. Purified terephthalic acid (PTA) Paraxylene High quality product with simple and mild oxidation and low product cost 10 1997... 

Terephthalic acid, however, was not available in commercial quantities at economically attractive prices when Whinfield and Dickson made their original discovery. After intensive efforts had been made it proved possible to purify paraxylene )>CH3 and oxidize it to terephthalic acid on... 

Terephthalic acid is prepared by oxidizing paraxylene with nitric acid... 

Two mononitroxylenes can be derived, theoretically, from orthoxylene, three from metaxylene, and but one from paraxylene. It follows, therefore, that the xylene boiling at 142°, from which two mononitro derivatives can be prepared, is orthoxylene, and that the ones boiling at 139° and 138° have the meta and para structure, respectively. The application of the so-called absolute method leads to the establishment of the structure of the three xylenes, which can serve, therefore, as reference-compounds. The three hydrocarbons yield three dibasic acids on oxidation orthoxylene gives phthalic acid, metaxylene gives isophthalic acid, and paraxylene gives terephthalic acid. The three phthalic acids become, thus, reference-compounds. Other compounds can be readily converted into xylenes or phthalic acids, and can, therefore, be used in the determination of structure. Thus, the three dibromobenzenes can be converted into the three xylenes by Fittig s synthesis. The transformations establish the structure of the halogen derivatives. From these other compounds may be prepared. An example will be instructive. The dibromobenzene which melts at 89° is converted into paraxylene when treated with methyl iodide and sodium —... 

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