Kinetics of COx formation in the homogeneous metal/bromide‐catalyzed aerobic oxidation of p‐xylene

The homogeneous metal/bromide-catalyzed aerobic oxidation of p-xylene with different catalyst concentrations was carried out, and the formation kinetics of COx including CO2 and CO was measured. The simplified elementary steps for the formation of COx were summarized, on the basis of which the kinetic model of COx formation was established. The model calculations were in good agreement with the experimental data for the CO2 formation and also successfully captured the first peak of the CO formation rate as a function of time. The obtained rate constants have narrow confidence intervals, among which only k1 and k2 are the adjustable parameters for different catalyst conditions. The decarboxylation of the carboxyl group in aromatic acid, the oxidation of the aryl radical, and the destruction of acetic acid are the major sources of CO2. The formation of CO mainly results from the destruction of acetic acid and the oxidation of the aryl radical. © 2012 Wiley Periodicals, Inc. Int J Chem Kinet 44: 277–283, 2012

[1]  Ling Zhao,et al.  Simulation of Secondary Oxidation of p-Xylene in Liquid Phase , 2011 .

[2]  Ling Zhao,et al.  Simplified Free-Radical Reaction Kinetics for p-Xylene Oxidation to Terephthalic Acid , 2008 .

[3]  W. Partenheimer.  The Complex Synergy of Water in Metal/Bromide Autoxidations. Part II. Effect of Water and Catalyst on the Aerobic Oxidation of Benzaldehydes and the Effect of Water on the Elementary Catalytic Pathways , 2005 .

[4]  T. Brill,et al.  Spectroscopy of Hydrothermal Reactions 23: The Effect of OH Substitution on the Rates and Mechanisms of Decarboxylation of Benzoic Acid , 2003 .

[5]  T. Brill,et al.  Spectroscopy of hydrothermal reactions, part 26: Kinetics of decarboxylation of aliphatic amino acids and comparison with the rates of racemization , 2003 .

[6]  Manish Sharma,et al.  Engineering Aspects of Industrial Liquid-Phase Air Oxidation of Hydrocarbons , 2000 .

[7]  Peter Glarborg,et al.  Experimental and kinetic modeling study of the oxidation of benzene , 2000 .

[8]  R. Sheldon.  Liquid Phase Autoxidations , 1995 .

[9]  Vladimir Agabekov,et al.  Effect of catalyst composition on decreasing of CO2 and CO formation in synthesis of aromatic acids , 1995 .

[10]  W. Partenheimer,et al.  Methodology and scope of metal/bromide autoxidation of hydrocarbons , 1995 .

[11]  W. Partenheimer,et al.  Nature of the Co-Mn-Br Catalyst in the Methylaromatic Compounds Process: Kinetic and Thermodynamic Studies , 1993 .

[12]  N. Ariko.  Effect of deuteration of solvent on process of catalytic oxidation of p-xylene and associated decarboxylation of acetic acid , 1991 .

[13]  P. Roffia,et al.  Byproduct identification in the terephthalic acid production process and possible mechanisms of their formation , 1984 .