UNCLASSIFIED
UNCLASSIFIED
Distribution A: Approved for Public Release
Characterization of MTNP (1-methyl-3,4,5-trinitro-1,2-pyrazole)
Philip Samuels*, Dr. Reddy Damavarapu, Henry Grau, Dr. Kimberly Spangler, Dr.
Kelley Caflin, Erik Wrobel
U.S. Army ARDEC
Energetics, Warheads, and Manufacturing Technology Directorate
Picatinny Arsenal, New Jersey 07806
Email: philip.j.samuels2.civ@mail.mil; Phone: 973-724-4064
ABSTRACT
The Ordnance Environmental Program (OEP) from RDECOM has recently funded
synthesis efforts evaluating new green synthesis routes to produce both RDX and TNT
replacements. MTNP (1-methyl-3,4,5-trinitro-1,2-pyrazole) is a low melting energetic
compound. Recently, MTNP has shown promise in terms of a relatively simple
synthesis route. ARDEC has characterized this compound from lab scale batches for
safety testing.
Thermo-chemical codes such as Cheetah and Jaguar were used to predict the Gurney
energy for this high energy material. MTNP was reported in literature using pyrazole,
chloro pyrazole and Methyl Pyrazole as starting materials. Our approach involves
commercially available 3-Nitropyrazole as starting compound and its synthetic
transformation to MTNP as outlined in the following scheme.
N
N
H
NO
2
PhCN
N
N
H
NO
2
150-180 C
N
N
NO
2
NO
2
O
2
N
3,5-DNP
HNO
3
Ac
2
O
N
N
NO
2
O
2
N
MDNP
Methylation
DMS
N
N
NO
2
O
2
N
O
2
N
H
3
C
H
3
C
MTNP
1,3-DNP
3-NP
Nitration
Small scale safety testing was completed, including impact, friction and electrostatic
discharge testing. The crystal density was determined by pycnometry and the thermal
stability was accessed via DSC, isothermal weight loss, and vacuum thermal stability (<2
cc gas/48hrs at 100°C). MTNP has proven to be compatible with most energetics and
metals. This paper will discuss the synthesis, thermal, sensitivity and analytical results
of pure MTNP.
Introduction
In modern ordnance there is a strong requirement for explosives having good thermal
stability, impact insensitivity and explosive performance. However, these requirements
are somewhat mutually exclusive. Those explosives having good thermal stability and
impact insensitivity exhibit poorer explosive performance and vice versa. TNT has been
the mainstay of melt-castable formulations. Among the TNT-based compositions known
for making melt-cast explosives, Composition B (TNT/RDX/Wax) is one of the more
widely known and practiced. As widely acknowledged in the art, however, melt-cast
explosives compositions such as Composition B have several drawbacks. In order to
overcome the above-mentioned problems with the existing melt-cast explosive
formulations and to meet the U. S. DoD requirements for future high performance
munitions systems, it is critical to develop other promising candidates, which possess
properties superior to TNT, in an environmentally benign manner. A number of
