Theoretical studies of the decomposition mechanisms of 1,2,4-butanetriol trinitrate.

Density functional theory (DFT) and canonical variational transition-state theory combined with a small-curvature tunneling correction (CVT/SCT) were used to explore the decomposition mechanisms of 1,2,4-butanetriol trinitrate (BTTN) in detail. The results showed that the γ-H abstraction reaction is the initial pathway for autocatalytic BTTN decomposition. The three possible hydrogen atom abstraction reactions are all exothermic. The rate constants for autocatalytic BTTN decomposition are 3 to 10 times greater than the rate constants for the two unimolecular decomposition reactions (O-NO cleavage and HONO elimination). The process of BTTN decomposition can be divided into two stages according to whether the NO concentration is above a threshold value. HONO elimination is the main reaction channel during the first stage because autocatalytic decomposition requires NO and the concentration of NO is initially low. As the reaction proceeds, the concentration of NO gradually increases; when it exceeds the threshold value, the second stage begins, with autocatalytic decomposition becoming the main reaction channel.