Promotion of O2 on the co‐pyrolysis of CHF3 and CH4 for VDF synthesis

• Published in: Greenhouse gases: science and technology 2017-10, Vol.7 (5), p.891-902
• Main Authors: Han, Wenfeng, Song, Yanyan, Liu, Wucan, Yang, Luteng, Tang, Haodong, Wang, Shucheng, Wu, Zhixing, Zhang, Jianjun
• Format: Article
• Language: English
• Subjects: chain reactions; Conversion; co‐pyrolysis; Free radicals; greenhouse gas; Methane; Promotion; Pyrolysis; Radicals; Reactors; trifluoromethane; VDF
• ISSN: 2152-3878; 2152-3878
• DOI: 10.1002/ghg.1687

Co‐pyrolysis of CHF3 and CH4 in the presence of O2 was investigated in a tubular reactor at temperatures between 700 and 860°C, atmospheric pressure, and residence time of 1.64 s. Under reaction conditions studied, introduction of O2 in the CHF3 and CH4 feed significantly improves the conversion of CH4, and while conversion of CHF3 almost stays unchanged. In the absence of O2, CH4 is activated by chain reactions which are initiated by the surface of the reactor. Following the introduction of O2, a series of additional chain reactions (reactions of CH4 with O2, O•, •HO2 and •OH radicals) generate more •CH3 radicals which are one of the key species for the formation of target product, CH2=CF2. Therefore, formation rate of CH2=CF2 is doubled under optimal reaction conditions. The suitable O2/CH4 feed ratio is suggested to be 0.06 for the formation of CH2=CF2. In addition, introduction of O2 in the feed decreases the formation of major byproduct C2F4 and C2HF3 significantly. After O2 is introduced, as more H• radicals are produced, improved formation rate of C2H3F results. © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd.