Theoretical kinetics of H-transfer and β-scission reactions following H-abstraction in n-butylamine during fuel-nitrogen combustion

Aliphatic amines are a significant nitrogenous fuel. To better understand the combustion of n-butylamine (CH3CH2CH2CH2NH2, N), the CBS method was used to compute the potential energy surfaces of the primary H-abstraction of n-butylamine by H, CH3 radicals, and NO2 radicals, as well as the H-transfer and β-scission reactions of n-butylamine radicals. The rate constants for the mentioned reactions were predicted between 300 and 2000 K based on transition state theory (TST) and RRKM theory. The results showed that the abstraction process for the H-atom by the addition of H radicals was more favored by the reaction kinetic. The yield of the cis-HONO by the addition of NO2 is highest. In the subsequent reactions, the breakage of the C–H bond was most competitive between 300 and 800 K, especially the H-transfer of int1 to int5, with the lowest forward energy of 15.81 kcal mol−1. The β-scission reactions became the main pathway for radical consumption with the increase in temperature. Subsequently, the rate constants with temperature and pressure have been fitted by the modified Arrhenius equation. The present work provides a theoretical basis and kinetic parameters for further development of the combustion model of n-butylamine.