Competence Centre for Energetic Materials (KCEM), Gammelbackavägen 6, S-69151 Karlskoga, Sweden.
J Phys Chem A. 2010 Mar 4;114(8):2845-54. doi: 10.1021/jp911277r.
Mechanistic pathways for the thermal decomposition of the solid-state energetic oxidizers ammonium dinitramide (ADN) and potassium dinitramide (KDN) have been deciphered by carefully considering previously performed experimental studies and using state of the art quantum chemical modeling of molecular clusters. Decomposition is governed by surface chemical processes, involving polarized (twisted) dinitramide anions of reduced stability. Under atmospheric and low-pressure conditions, the rate-determining step for the decomposition of these dinitramide salts is the dissociation into NO(2) and NNO(2)(-) radicals. The activation barriers for these steps are estimated to be 30 and 36 kcal/mol for ADN and KDN, respectively. The known stabilizing effect of water is explained by its hydrogen bonding ability, which counteracts polarization of surface dinitramides. The reactivity of ADN toward various chemical environments is likely explained through metastable decomposition radical intermediates. Donation of hydrogen bonds, antioxidant character, and basicity are properties believed to correlate with a compound's ability to act as a stabilizer for dinitramide salts.
通过仔细考虑先前进行的实验研究，并使用最先进的分子簇量子化学建模，揭示了固态含能氧化剂硝酸铵（ADN）和硝酸钾（KDN）的热分解的机制途径。分解受表面化学过程控制，涉及稳定性降低的极化（扭曲）二硝酰胺阴离子。在大气和低压条件下，这些二硝酰胺盐分解的速率决定步骤是分解成 NO(2) 和 NNO(2)(-)自由基。这些步骤的活化能垒分别估计为 30 和 36 kcal/mol。水的已知稳定作用是通过其氢键形成能力来解释的，该能力可以抵消表面二硝酰胺的极化。ADN 对各种化学环境的反应性可能通过亚稳态分解自由基中间体来解释。氢键供体、抗氧化特性和碱性被认为与化合物作为二硝酰胺盐稳定剂的能力相关。
