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Acid‐Base Interactions in Energetic Materials: I. The Hard and Soft Acids and Bases (HSAB) Principle–Insights to Reactivity and Sensitivity of Energetic Materials
Author(s) -
Koch ErnstChristian
Publication year - 2005
Publication title -
propellants, explosives, pyrotechnics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.56
H-Index - 65
eISSN - 1521-4087
pISSN - 0721-3115
DOI - 10.1002/prep.200400080
Subject(s) - hsab theory , reactivity (psychology) , sensitivity (control systems) , base (topology) , energetic material , chemistry , acid–base reaction , computational chemistry , materials science , nanotechnology , organic chemistry , mathematics , engineering , medicine , alternative medicine , pathology , mathematical analysis , electronic engineering , explosive material
The chemistry of energetic materials can be described applying acid‐base reaction formalism. Addressing the HSAB concept, the number of electrons transferred, Δ N , in an acid‐base reaction, allows for description and prediction of properties of composite and homogeneous materials. At first Δ N helps in estimating the rate of reaction of binary systems with either given fuel or oxidizer. Nevertheless Δ N is only a relative number thus the range of comparability remains narrow. At second Δ N can be used as a measure for the sensitivity of homogeneous explosives. The increased reactivity of hypothetical fragments to recombine in a reaction such as R 3 C . + . NO 2 =R 3 C−NO 2 given by Δ N correlates very well with experimentally determined reduced impact sensitivity of 1,3,5‐trinitrobenzene compounds. On the contrary the rising impact sensitivity of metal azides correlates with rising values of Δ N of M n+ /N 3 − reaction because increased reactivity, that is increased electron transfer from the azide anion to the metal cation triggers formation of the azide radical ( . N 3 ). The latter then decomposes rapidly to give dinitrogen. This increased reactivity/sensitivity of metral azides coincides with covalent bonding whereas ionic azides are relatively insensitive.