Thermal Decomposition of TATB—Review of Molecular Characterization
Evan M. Kahl and John G. Reynolds
Lawrence Livermore National Laboratory
Livermore CA 94550
ABSTRACT
The behavior of TATB when exposed to thermal insults is important to understand on a molecular level when devel-
oping safety response procedures. This manuscript summaries the current state of studies on the thermal decomposi-
tion of TATB and subsequent decomposition products.
INTRODUCTION
TATB (1,3,5-triamino-2,4,6-trinitro-benzene) is a fascinating molecule to study from a fundamental to applied
perspective. The molecule was first prepared in 1888 [1] by Jackson and Wing, and since that time has been the
subject of many studies because of the unique structural configuration. From a fundamental perspective, the full
substitution around the benzene ring with alternating donor-acceptor groups yields interesting reactive properties. The
crystalline structure [2] shows the organization of the lattice has a similar appearance to two-dimensional sheets of
graphite instead of a tertiary structure expected from an organic compound with numerous heteroatoms. The donor-
acceptor configuration has been also studied from a computational aspect [3] showing an unusual electron density
distribution straining the bonding of benzene ring. These molecular features apparently lead to a stability that makes
TATB only slightly soluble even in the more robust organic solvents, such as DMSO and HMPA [4] and shows an
relatively inert [5] to reactivity. From the applied view, TATB has extensively used as an insensitive explosive. The
unusual overall structure makes it resilient to insults such as impact, friction and spark, as well as the reasonably robust
thermal properties make it a thermally stable compared to other military munitions [6]. The unusual properties are
also reflected in the non-linear optics applications [7] where the non-dipolar molecule should not have the strong
second-generation harmonic needed for the optical properties that it displays. These features have gleaned more than
a pedestrian interest in this unusual molecule.
The use of TATB as a munition has stimulated interest in determining the origin and extent of the unusual stabil-
ity. The principal drivers for this are the potential extreme conditions the explosive is exposed to as a munition.
Conditions such as extreme temperature changes, radiation and impact have the potential to alter the chemical and
physical properties of TATB. These types of changes can affect the performance properties as well alter protocols for
safe handling and storage. Of particular interest is the thermal stability, which studies have yielded many efforts to
understand and model the thermal degradation pathways of TATB. This manuscript reviews the published background
into the thermal reaction pathways of TATB and TATB related materials, such as polymer bonded explosives, and
reviews the efforts to characterize the decomposition products on a molecular level.
SUMMARY OF TATB THERMAL DECOMPOSITION PATHWAYS
The bulk of the research into the thermal decomposition behavior of TATB has occurred in the last fifty years.
Early work concentrated on determining global kinetics and activation energies of thermally initiated reactions. This
work gradually led to efforts to characterize molecular species. From this perspective, Figure 1 summarizes some of
the major species identified in this decomposition route. Currently, benzo-furazans (or furazans used here), TATB-
F
1
, -F
2
, and -F
3
, are considered to be the main components in the first steps of decomposition. Benzo-furoxans (or
furoxans used here), TATB-F
x1
, F
x2
, and F
x3
, are still being considered, but probably play an important part in non-
thermal decomposition processes, such as irradiation and impact.
During the thermal process, after formation from TATB, these compounds begin to unravel, probably first losing
the appendages of the aromatic ring followed by cleavage of the ring. This leads to many potential molecular com-
pounds of various structures that contain ring fragments and lead to the formation of light gases. Table 1 summarizes
essentially all the molecular species detected as ions in mass spectrometry (MS) studies of thermal decomposition of
TATB. Towards the end of the decomposition process, after most the functionality has disappeared, a carbonaceous
residue is formed. This residue appears to have very loose structure and may have some integration of C-N structures
into the carbon framework.
X-ray photoelectron spectroscopy (XPS) and MS data with supporting infrared spectroscopy (IR) and Raman data
provides the bulk of the evidence that leads to identifying the furazans and other products. MS and IR have also been
