(600aw) Gas-Phase Oxidation of Hexafluoropropene with Molecular Oxygen: Reaction Chemistry and Kinetics

The high-temperature, gas-phase oxidation of hexafluoropropene with molecular oxygen was studied in an isothermal tubular reactor operating under laminar flow. Measurements were conducted at a total pressure of 450 kPa and over the temperature range of 463 to 493 K. Experimental data were fitted to a proposed kinetic model. The performance of the long, narrow, coiled reactor tube used for generating the rate data was found to closely approach that of a plug flow reactor. Reactor modelling for the purposes of kinetic parameter identification was based on the latter idealized flow pattern. A previously accepted reaction mechanism, based on the reactive routes for the interaction of oxygen atoms with fluoroethylenes, was modified to include a step for the formation of polyoxadifluoromethylene oligomers via radical units evolving from the interaction of hexafluoropropene and molecular oxygen. It was shown that the proposed kinetic model could reconcile a significant portion of the experimental data. The new model was consistent with the experimental observations, atomic balances and thermochemical constraints.