五氟乙烷灭火剂高温热解机理研究  

Study on thermal decomposition mechanism of pentafluoroethane fire extinguishing agent

作　　者：冒爱琴[1,2] 杨明君[2,3] 俞海云[2] 张品[1] 潘仁明[1] 

机构地区：[1]南京理工大学化工学院,江苏南京210094 [2]安徽工业大学材料科学与工程学院,安徽马鞍山243002 [3]哥奉哈根大学化学系纳米科学巾心,丹麦哥本哈根DK-2100

出　　处：《山东大学学报（理学版）》2013年第1期51-55,共5页Journal of Shandong University(Natural Science)

基　　金：国家科技支撑项目(2008BAK40B02)

摘　　要：根据均裂的化学键类型提出了五氟乙烷(C2HF5)的9条初级裂解反应路径,采用DFT/B2LYP/6-31G*、DFT/B2LYP/6-311G**、MP2/6-31G*和MP2/6-311G**方法计算了C2F5H各裂解反应的焓变、中间态分子模型以及反应中生成的卡宾的能态。结果表明C2HF5裂解最易发生H转移反应生成C2F4;伴随H转移生成CF3CF:卡宾,F转移生成CHF:,C—C键断裂生成CF2H.和CF3.,自由基或卡宾之间相互结合生成微量的C2F6、C4F8和C4F10等气体产物。热解实验证实,C2HF5在750～850℃时主要发生脱HF反应生成C2F4,随着反应温度的增加,C2HF5分解程度提高。理论计算的C2HF5裂解产物与实验检测结果一致。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 en- ergies of carbenes have been studied theoretically using DFT/B2LYP/6-31G~ , DFT/B2LYP/6-311G＊＊ , MP2/6- 31 G ＊ , and MP2/6-31 l G ＊＊ methods. Of a total of 9 primary reaction pathways, the decomposition of C2 HF5 to form C2 F4 is the most important initiation mechanism. With the H-transfer reaction to CF3 CF： carbene, F-transfer reaction to CHF：, and C-C bond fission reaction to CF2H - and CF3 · , a trace of products such as C2F0 , C4F8 and C4F10 are pro- duced due to the reactions between radical and carbene. It is proved by thermal decomposition that hydrogen fluoride e- liminated to form C2F4 is the main reaction between 750 ℃ and 850 ℃. As the reaction temperature increases, the ther- mal decomposition degree of C2FsH become higher. Theoretically calculated results are consistent with the experimental observation.

关 键 词：五氟乙烷 热解机理 理论计算 热分解 

分 类 号：X932[环境科学与工程—安全科学] O643[理学—物理化学]