Atomic Insights Into the Reaction Characteristics of [AMIM]BH 4 Ionic Liquid Based on ReaxFF Molecular Dynamics Simulation
Chao Cao, Daolun Liang, Yanjing Wu, Binghong ChenABSTRACT
Boron‐based ionic liquids are a new generation of self‐igniting propellants. The experiment obtained its basic combustion characteristics, but there is insufficient understanding of its detailed reaction mechanism. In this paper, the ReaxFF MD simulation method was adopted to explore the reaction mechanism of [AMIM]BH 4 ionic liquid at the microscopic molecular level. The main reaction pathway of the [AMIM]BH 4 /HNO 3 system was obtained. Research has found that the [AMIM]BH 4 /HNO 3 system is dominated by the reaction between BH 4 and HNO 3 . The proton transfer between BH 4 and HNO 3 in the system is the key to initiating the reaction, which generates the transient intermediates BH 3 and H 2 NO 3 . Subsequently, the system is divided into two reaction pathways. Most of the BH 3 will continue to dehydrogenate in the system to form BH 2 , while the other part will directly participate in the reaction in the system to generate H 2 BO intermediates. Both reaction pathways will eventually produce boron‐containing oxides such as BO 2 . The decay of the [AMIM] cation begins with the attack of multiple HNO 3 , causing continuous reactions such as ring opening, oxygen uptake and chain breaking. In addition, a dynamic collision model was established to simulate the collision process between cations and anions and the oxidant in practical applications. The mean displacement curves (MSD) of [AMIM]BH 4 to HNO 3 and the diffusion coefficient D under different collision velocities were obtained. It was found that when the diffusion coefficient D was large, the initial chemical reaction in the subsequent system would be more intense under the corresponding conditions.