J4 ›› 2013, Vol. 48 ›› Issue (1): 51-55.

• Articles • Previous Articles     Next Articles

Study on thermal decomposition mechanism of  pentafluoroethane fire extinguishing agent

MAO Ai-qin1,2, YANG Ming-jun2, 3, YU Hai-yun2, ZHANG Pin1, PAN Ren-ming1*   

  1. 1. School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu, China;
    2. School of Materials Science and Engineering, Anhui University of Technology, Maanshan 243002, Anhui, China;
    3. Center for Nanoscience and Technology, Department of Chemistry, University of Copenhagen,
    Copenhagen DK2100, Danmark
  • Received:2012-10-16 Online:2013-01-20 Published:2013-01-15

Abstract:

Nine primary pyrolysis pathways of pentafluoroethane (C2HF5) are proposed based on the chemical bond types of the homolytic cleavage. The enthalpy of decomposition reaction for C2F5H, transitionstate molecules, and energies of carbenes have been studied theoretically using DFT/B2LYP/6.31G*, DFT/B2LYP/6.311G**, MP2/6.31G*, and MP2/6.311G** methods. Of a total of 9 primary reaction pathways, the decomposition of C2HF5 to form C2F4 is the most important initiation mechanism. With the Htransfer reaction to CF3CF: carbene, F-transfer reaction to CHF:, and C-C bond fission reaction to CF2H·and CF3·, a trace of products such as C2F6, C4F8 and C4F10 are produced due to the reactions between radical and carbene. It is proved by thermal decomposition that hydrogen fluoride eliminated to form C2F4 is the main reaction between 750℃ and 850℃. As the reaction temperature increases, the thermal decomposition degree of C2F5H become higher. Theoretically calculated results are consistent with the experimental observation.

Key words: pentafluoroethane; decomposition mechanism; theoretical calculation; thermal decomposition

No related articles found!
Viewed
Full text


Abstract

Cited

  Shared   
  Discussed   
No Suggested Reading articles found!