Li Hangchen, Hua Min, Pan Xuhai, Li Shunchao, Guo Xinxin, Zhang Han, Jiang Juncheng
College of Safety and Engineering, Nanjing Tech University, Nanjing, 210009, China.
Jiangsu Key Laboratory of Urban and Industrial Safety, Nanjing, 210009, Jiangsu, China.
J Mol Model. 2019 Jul 31;25(8):255. doi: 10.1007/s00894-019-4136-y.
Dry powder fire-extinguishing agent is one of Halon substitutes due to its superior fire-extinguishing performance, non-toxicity, and environmental friendliness. As one of the most widely used dry powders, ABC dry powder has attracted wide attention. Understanding its reaction mechanism is important to the design of more efficient compound dry powder based on it. When ABC dry powder was applied to the flame, ammonium dihydrogen phosphate (the main fire-extinguishing component of ABC dry powder) would rapidly decompose into phosphoric acid (HPO) and ammonia. Therefore, in order to figure out the chemical reaction mechanism of ABC dry powder and active radicals, the main focus of this paper is on the HPO. Analysis of the electrostatic potential on van der Waals surface of HPO was carried out. Besides, detailed theoretical investigation has been performed on the mechanism, kinetics, and thermochemistry of the reactions of HPO with H, OH, and CH radicals and further decomposition of HPO using M06-2X/6-311G(d,p)//CCSD(T)/cc-pVTZ level of theory. Mayer bond order for all intrinsic reaction coordinate points was also calculated. Finally, it is theoretically proved that ABC dry powder extinguishes the fire mainly by chemical inhibition on H and OH radicals. Grapical Abstract .
干粉灭火剂因其优异的灭火性能、无毒和环境友好性而成为哈龙替代品之一。作为使用最广泛的干粉之一，ABC干粉受到了广泛关注。了解其反应机理对于基于它设计更高效的复合干粉很重要。当ABC干粉应用于火焰时，磷酸二氢铵（ABC干粉的主要灭火成分）会迅速分解为磷酸（HPO）和氨。因此，为了弄清楚ABC干粉与活性自由基的化学反应机理，本文主要聚焦于HPO。对HPO范德华表面的静电势进行了分析。此外，使用M06-2X/6-311G(d,p)//CCSD(T)/cc-pVTZ理论水平，对HPO与H、OH和CH自由基反应的机理、动力学和热化学以及HPO的进一步分解进行了详细的理论研究。还计算了所有内禀反应坐标点的迈耶键级。最后，从理论上证明了ABC干粉主要通过对H和OH自由基的化学抑制作用来灭火。图形摘要
