Abstract: Excess burning of pseudocumene, lowering concentration of use of cobalt and replace it with manganese by the use of less than the previously used 3.0 to 0.1 milligram atom of zirconium, preferable from 0.005 up to 0.075 milligram atom of zirconium, per 1.0 milligram atom of total of transition metals cobalt and manganese or cobalt, manganese and cerium.

Abstract: Catalytic liquid phase molecular oxygen oxidation of methyl-substituted aromatic hydrocarbons having two or more methyl-substituents on adjacent ring carbon atoms in acetic acid reaction medium have, in general, resulted in a substantial production of the desired ortho-oriented di-, tri-, and higher polycarboxylic substituted aromatic acids but also in the co-production of substantial amounts of oxygenated intermediates including methyl-substituted mono- and non-ortho polycarboxylic acids. Several theories have been proposed, including inherent auto-inhibiton, for such incomplete oxidations.

Abstract: This invention relates to the preparation of o-phthalic acid by the oxidation of liquid o-xylene with a source of molecular oxygen at a temperature in the range of from 150.degree. C. up to 235.degree. C. in the presence of catalysis provided by the combination of components which include a source of bromine and at least cobalt as metal oxidation catalyst, in the presence of liquid water in an amount to activate said catalysis and solubilize a catalytically effective amount of metal oxidation catalyst in liquid phthalic acid and under conditions which retain substantially all the o-phthalic acid in the free acid form but in the absence of any material extraneous to the oxidation reaction or its products as solvent.Such preparative process results in yields of 85 to 92 mole percent and higher to o-phthalic acid in but a single oxidation step with recycle thereto of only o-xylene vaporized from the reaction zone and recovered.

Abstract: This invention relates to the neat air oxidation of liquid o-xylene in a continuous manner in a single step to overcome the limited conversion of the process of British Patent Specification No. 856,245 or of the process of U.S. Pat. No. 3,920,735. More specifically this invention overcomes the limited conversion of o-xylene by its single step air oxidation in the presence of catalysis provided by ions of cobalt, manganese and bromine not only by maintaining the proper relationship of temperature, pressure and free water concentration in the reaction mixture to minimize the conversion of o-phthalic acid to its intramolecular anhydride but also by conducting the oxidation in the presence of small amounts of acetic or benzoic acid to make miscible the otherwise immiscible liquid phases of liquid o-xylene and liquid o-phthalic acid containing components of catalysis and free liquid water.