Abstract:

Fluorine amines are one of the most promising nitrogen-containing compounds as halon substitutes. As a typical fluorine amine, perfluorotriethylamine has good fire-extinguishing effect. In order to reveal the pyrolysis mechanism of (C₂F₅)₃N, its pyrolysis products under different temperature conditions are obtained by using GC-MS, and then the pyrolysis reaction paths are theoretically calculated by using Gaussian. The results show that the initial pyrolysis temperature of (C₂F₅)₃N is about 600℃, and the complete pyrolysis is around 750℃, by keeping the residence time at 10 s. The pyrolysis products are C₄F₉N, C₃F₇N, C₂F₆ and C₃F₈. The volume fraction of C₄F₉N is the largest at a low pyrolysis temperature, while the volume fraction of C₃F₇N is the largest at a high pyrolysis temperature. In the calculation of the pyrolysis reaction path of (C₂F₅)₃N, there is one reaction pathway would generate C₃F₈ after the breaking of C—C bond in the (C₂F₅)₃N molecule. In another pyrolysis reaction path of (C₂F₅)₃N, C₂F₆ and the stable product C₄F₉N would be generated after the breaking of C—N bond. The breaking of C—N bond in (C₂F₅)₃N would produce an unstable product N(C₂F₅)₂, the followed breaking of the C—C bond will generate C₃F₇N. The main pyrolysis products of (C₂F₅)₃N are C₄F₉N and C₃F₇N, the two products have CN double bonds and can more easily interact with the combustion active.

Key words: (C₂F₅)₃N, pyrolysis, Gaussian calculation, reaction path, mechanism

摘要：

氟胺类物质是最有希望作为哈龙替代品的含氮化合物之一，全氟三乙胺作为典型的氟胺类物质具有良好的灭火效果。为研究全氟三乙胺热解机理，在管式加热炉内对全氟三乙胺进行热分解，通过GC-MS分析全氟三乙胺在不同温度条件下的热解产物，并用Gaussian软件对其热解反应路径进行理论计算。结果表明：保持停留时间为10 s，全氟三乙胺的初始热解温度为600℃，750℃完全热解，热解产物有C₄F₉N、C₃F₇N、C₂F₆和C₃F₈，热解温度较低时C₄F₉N体积分数最大，热解温度较高时C₃F₇N体积分数最大。在全氟三乙胺热解反应路径计算中，全氟三乙胺分子中的C—C键断裂后存在1条反应路径，可生成实验产物中的C₃F₈；全氟三乙胺分子的C—N键断裂后存在3条反应路径，可生成实验产物中的C₃F₇N、 C₄F₉N和C₂F₆。全氟三乙胺热解后产生的CF₃自由基可与H、OH自由基发生反应，从而产生灭火作用。此外，其热解产物C₄F₉N和C₃F₇N具有CN双键，更容易与燃烧活泼自由基·OH、·H发生化学作用，对研究全氟三乙胺的灭火机理具有十分重要的意义。

关键词: 全氟三乙胺, 热解, 高斯计算, 反应路径, 机理