Abstract:

The current environmental problems are becoming increasingly prominent, and the natural refrigerant ammonia as an environmentally friendly refrigerant has once again attracted widespread attention in the scientific community. However, NH₃ has the problem of flammability and explosion, and there are certain safety hazards in practical applications. In this paper, we adopt the quantum chemical density generalized theory calculation method to investigate the combustion and flame-retardant mechanism of NH₃ at the calculation level of M06-2X/6-311+G(d, p), and obtain the microscopic reaction path of the reaction process. It is shown that NH₃ can react with H, O and OH radicals in three ways: firstly, it undergoes its own cleavage reaction to produce H radicals; secondly, it collides with oxygen to produce OOH radicals; thirdly, it collides with reactive radicals to produce new reactive radicals, and NH₃ can react with H, O and OH radicals, and the reaction has a low energy barrier. In addition, the microscopic flame retardant paths of two typical flame retardant groups, F and CF₃, to the combustible molecule NH₃ were calculated to verify their flame retardant effects. In this paper, the combustion and flame retardant mechanism of the combustible work material ammonia is investigated from the microscopic molecular perspective, which provides a reference for the combustion and flame retardant mechanism of the new generation of low greenhouse effect work materials.

Key words: ammonia, molecular simulation, flammability, flame retardant

摘要：

当前环境问题日益突出，天然工质氨作为环保性制冷剂再次引起科学界的广泛重视。但NH₃存在可燃可爆性问题，在实际应用中存在着一定的安全隐患。采用量子化学密度泛函理论计算方法，在M06-2X/6-311+G（d，p）的计算水平上，对NH₃的燃烧及阻燃机理开展研究，得到反应过程的微观反应路径。研究表明，NH₃可通过三种方式发生燃烧微观反应，一是发生自身裂解反应，生成H自由基；二是与氧气发生碰撞反应，生成OOH自由基；三是与活性自由基发生碰撞反应，生成新的活性自由基，NH₃可与H、O、OH自由基反应，反应能垒较低。此外，还计算了两种典型的阻燃基团F和CF₃对可燃分子NH₃的微观阻燃路径，验证其阻燃效果。本文从微观分子的角度考察了可燃工质氨的燃烧及阻燃机理，为新一代低温室效应工质的燃烧及阻燃机制提供了参考。

关键词: 氨, 分子模拟, 可燃性, 阻燃