Catalytic oxidation of chlorinated benzenes over V2O5/TiO2 catalysts: The effects of chlorine substituents

• Kinetic data of chlorobenzene and 1,3,5-trichlorobenzene was obtained.
• Electron-withdrawing effect was demonstrated by in-situ FTIR.
• Pathways for the catalytic oxidation of 1,3,5-trichlorobenzene was proposed.

Chlorobenzene and 1,3,5-trichlorobenzene were chosen as model pollutants of chlorinated benzenes. Catalytic (kinetic) studies and in-situ FTIR experiments were conducted over V2O5/TiO2 catalysts to investigate the oxidation behavior of these two chlorinated benzenes. Different oxidation rates were observed in the catalytic study, which was ascribed to their molecular structural properties. Oxidation products and by-products were analyzed both on-line by GC and off-line by GC-MS, and slight difference was observed for these two chlorinated benzenes. Similar surface species on the catalysts could be easily identified in the in-situ FTIR curves. Supported by these results, a possible reaction pathway for catalytic oxidation of 1,3,5-trichlorobenzene was accordingly proposed. Noteworthy, the effect of the chlorinated degree on the catalytic oxidation was discussed, and it is well demonstrated that the structural and electronic factors of the chlorinated benzenes, and the influence of chlorine to the active vanadium sites, play important roles in the oxidation process.

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