A comparative on the thermal decomposition and fire‐extinguishing performance of C 5 F 8 and C 5 F 7 Cl

• Published in: International journal of quantum chemistry Vol. 123; no. 20
• Main Authors: Chang, Zhenxiang, Yu, Rourou, Li, Shukai, Guo, Yueying, Tan, Zhaoyang, Zhang, Xiao, Liu, Jiexiang
• Format: Journal Article
• Language: English
• Published: 15.10.2023
• ISSN: 0020-7608; 1097-461X
• DOI: 10.1002/qua.27198

Abstract Compared with fluorinated cycloalkanes and liner olefins, the degradation of chlorofluorocycloolefins is much easier with good environmental friendliness. However, the fire‐extinguishing performance of chlorofluorocycloolefins has been rarely explored. In this study, the fire‐extinguishing performance and working mechanism of octafluorocyclopentene (C 5 F 8 ) and 1‐chloro‐2,3,3,4,4,5,5‐heptafluorocyclopentene (C 5 F7Cl) were studied by combined experimental and theoretical approach. It was found that, compared to C 5 F 8 , the asymmetry of C 5 F 7 Cl agent with the chlorine atom possesses a reduced energy barrier in pyrolysis process and its reaction with OH· radicals. Moreover, chlorine‐containing unsaturated active groups and CF 2 · radicals generated in C5F7Cl pyrolysis can effectively capture flame radicals. As a result, a relatively low minimum extinguishing concentrations (MECs) for suppressing methane‐air (5.37 vol%) and propane‐air flame (5.93 vol%) is achieved outperforms that of C 5 F 8 (6.73 and 7.74 vol%), even better than reported fluorinated cycloalkanes and chlorofluoroolefins agents. This study shows that chlorofluorocycloolefins are promising Halon substitutes over perfluorocyclic olefins in fire‐extinguishing performance.