Experimental and computational studies of the pyrolysis of CBrF3, and the reaction of CBrF3 with CH4

A detailed reaction mechanism has been used to model experimental data on the pyrolysis of CBrF3 and the non-oxidative gas-phase reaction of CBrF3 with CH4 at the temperature of 650-1100 K, residence time of 0.1-2.0 s and atmospheric pressure. Although the conversion levels of both CBrF3 and CH4 can be predicted reasonably well, there are significant discrepancies over the product profiles of the reactions. C2F6 is the only carbon-containing product of CBrF3 pyrolysis predicted by the existing pyrolysis mechanism, while a range of products, such as CF4, CBr2F2 and C4F10, were detected experimentally. For the reaction of CBrF3 with CH4, the existing mechanism adequately predicts the yield of CHF3, but considerably over predicts the production of CH3Br and C2F6, and under predicts the formation of many other species, including C2H2F2, C2H4, and C2H2. In addition, CHBrF2 was detected in appreciable amounts experimentally, but was not predicted at all using the existing mechanism. Through a detailed analysis of various reaction pathways, kinetic parameters of several existing reactions have been re-estimated, and a number of additional reaction steps have been included, resulting in a new reaction scheme. This modified scheme is able to significantly improve agreement between model prediction and experimental data. (C) 2000 Elsevier Science Ltd. All rights reserved.