jp408992n_si_001.pdf (1.05 MB)
Speciation of the Products of and Establishing the Role of Water in the Reaction of TNT with Hydroxide and Amines: Structure, Kinetics, and Computational Results
journal contribution
posted on 2013-11-07, 00:00 authored by Christopher
A. Latendresse, Syrena C. Fernandes, Sangmin You, William B. EulerThe
reaction of trinitrotoluene (TNT) with bases has been investigated
by NMR and visible spectroscopy methods. Hydroxide ion was found to
react in one of two ways, either by deprotonation of the methyl group
or by nucleophilic attack on the aromatic ring to form a σ adduct.
The rate of each mode of reaction depends upon the polarity of the
solvent. In tetrahydrofuran (THF), σ adduct formation is rapid
and the long-term equilibrium product is deprotonation of the methyl
group. When the solvent is methanol (MeOH), the two reactions have
similar rates and the σ adduct becomes the majority product.
Amines were found to be ineffective in directly deprotonating TNT
or in forming σ adducts. Rather, the amines react with ambient
water to generate hydroxide ion, which then reacts with TNT. The solvent
choice and water content are crucial to understanding the reactivity
of bases with TNT. To assist in the interpretation of the experimental
results, computational analysis was performed at the B3LYP/6-311+G**//HF/6-311+G**
level to determine the thermodynamics of the reactions of TNT. The
SM8 implicit solvation model was applied to converged geometries and
suggested a strong solvation effect upon product formation. Thermodynamic
analysis suggested a significant preference of alkoxide or hydroxide
attack versus amine attack in any modeled dielectric, consistent with
the experimental observations.