Communications
temperature of decomposition (189.28C). Given the tempera-
ture profile and low sensitivity of 4, coupled with its calculated
detonation pressure and detonation velocity, this material has
the potential to be a TNT replacement in melt-castable and
Composition B based formulations. In addition, 4 has a calculat-
3,3’-Bis-isoxazole-5,5’-bis-methylene dinitrate (4)
To a 250 mL round-bottom flask equipped with a stir bar was
added 150 mL of 90% HNO . The flask was cooled to 08C in an
3
ice-water bath, and bis-isoxazole (3) (17.6 g, 0.120 mol, 1.00 equiv)
was added portionwise over a 10 min period. No exothermic reac-
tion was observed during addition. The reaction mixture was left
in the ice-water bath and stirred for 4 h, during which time the ice-
water bath melted, and the reaction mixture had warmed to room
temperature. The reaction mixture was poured onto ice, a white
solid formed, and this solid was collected by Bꢂchner filtration. The
solid was left to dry on the Bꢂchner funnel under suction for 3 h in
a well-ventilated fume hood to afford 23.6 g (92%) of dinitrate 4
ed specific impulse (I ) of 206.2 s, possesses some Lewis basic
sp
character, and pendant alkyl nitrate functionality. Hence, this
material may serve as an energetic plasticizer in insensitive
munitions and in nitrate-based propellant formulations, poten-
tially reducing volatility/migration during thermal and mechan-
ical shock.
In summary, an efficient scalable route to 4 has been dis-
closed, and the compound exhibits a low sensitivity to impact,
friction, and electrostatic discharge. This material has the po-
tential to serve multiple functions. The sensitivity profile and
performance properties of 4 suggests that this material has
the potential to serve as: a) A TNT replacement in melt-casta-
ble and Composition B formulations; b) a potential energetic
plasticizing ingredient with nitrocellulose-based propellant for-
mulations in an effort to reduce the volatility/migration issues
that arise during cook-off.
as a white powder. m.p.=92.08C (onset), 95.98C (peak); T
=
dec
À1
1
189.28C (onset), 221.28C (peak); IR: nNO =1643, 1605 cm ; H NMR
(400 MHz, [D
]DMSO): d=7.28 (s, 2H, ÀCH), 5.90 ppm (s, 4H, À
6
1
3
CH ÀONO ); C NMR (100 MHz, [D ]DMSO): d=166.57 (NÀCÀC),
2
2
6
1
54.21 (OÀCÀC), 104.87 (ÀCH), 64.67 ppm (-CH -).
2
Acknowledgements
We are indebted to the U.S. Army for funding of this work. Dr.
Rose A. Pesce Rodriguez is gratefully acknowledged for her assis-
tance in acquiring the DSC data.
Experimental Section
Keywords: energetic materials · explosives · nitrates ·
propellants
Chemicals and solvents were used as received from Sigma–Aldrich.
1
H NMR spectra were recorded using a 400 MHz Bruker instrument.
1
3
C NMR spectra were recorded using a 100 MHz Bruker instru-
ment. The chemical shifts quoted in ppm in the text refer to typical
[1] T. M. Klapçtke, Chemistry of High-Energy Materials, 3rd ed., De Gruyter,
Berlin, Germany, 2015.
1
13
standard tetramethylsilane ( H, C) in [D ]DMSO as the solvent.
6
Melting points and decomposition temperatures were measured at
À1
[3] J. J. Sabatini, K. D. Oyler, Crystals 2016, 6, 5.
a heating rate of 58Cmin using a TA instruments Q10 DSC instru-
[
4] P. Samuels, Insensitive Munitions and Energetic Materials (IMEM) Symposi-
ment. Infrared spectra were measured with a Bruker Alpha-P FTIR
instrument.
[
[
6] a) T. L. Davis, The Chemistry of Powder and Explosives, John Wiley & Sons
Inc., New York, 1943; b) A. Nobel, Swedish Patent 2158, 1889; c) A.
Nobel, British Patent 4179, 1875.
Impact sensitivity testing was performed using a modified Picatin-
ny Arsenal drophammer, and friction sensitivity was performed
using a BAM friction apparatus in accordance with NATO STANAG
guidelines. ESD sensitivity testing was performed using an ABL
testing machine.
[
7] P. P. Naoum, Nitroglycerine and Nitroglycerine Explosives, Williams and
Wilkins, Baltimore, 1928.
[
8] W. O. Snelling, C. G. Storm, The Behavior of Nitroglycerin When Heated,
Department of the Interior, Burueau of Mines, Washington, DC, 1912,
p. 12.
[
9] a) M. Hu, X. He, Z. Niu, Z. Yan, F. Zhou, Y. Shang, Synthesis 2014, 46,
5
10–514; b) P. Grꢂnanger, E. Fabbri, Gazz. Chim. Ital. 1959, 89, 598.
5
,5’-Dihydroxymethyl-3,3’-bis-isoxazole (3)
[
[
To a 5 L round-bottom flask equipped with a stir bar was added
P. Samuels, R. Damavarapu, A. Paraskos, E. Cooke, V. Stepanov, P. Cook,
K. Caflin, R. Duddu, Insensitive Munitions and Energetic Materials (IMEM)
Symposium„ Rome, Italy, 19–21 May 2015, pp. 1–10.
1
.9 L of MeOH, dichloroglyoxime (2) (30 g, 0.191 mol, 1.00 equiv),
and propargyl alcohol (53.6 g, 55.2 mL, 0.956 mol, 5.00 equiv). To
the reaction mixture was added a 30 wt% solution of NaHCO3
(
64.3 g, 670 mL, 0.77 mol, 4.00 equiv) over 6 h. After addition of
the base was completed, the reaction mixture was stirred an addi-
tional 10 h. The reaction mixture was transferred to the rotary
evaporator, and was concentrated in vacuo. To the resultant solid
[
13] a) H. Feuer, Nitrile Oxides, Nitrones, and Nitronates in Organic Synthesis
material was added 2 L of H O, and the reaction mixture was
2
2
cooled to 08C. The solid was collected by Bꢂchner filtration, trans-
ferred to a drying tray, and dried 16 h in a well-ventilated fume
hood to afford 28.1 g (75%) of bis-isoxazole 3 as an off-white
À1
1
powder. m.p.=163.48C (peak); IR: nOH =3371 cm
,
H NMR
[
14] NATO Standardization Agreement (STANAG) on Explosives, Impact Sen-
sitivity Tests, no. 4489, 1st ed., September 17, 1999.
[15] NATO Standardization Agreement (STANAG) on Explosive, Friction Sen-
(
4
1
400 MHz, [D ]DMSO): d=6.85 (s, 2H,ÀCH), 5.77 (broad s, 2H, ÀOH),
6
13
.65 ppm (s, 4H, ÀCH ÀOH). C NMR (100 MHz, [D ]DMSO): d=
2
6
74.68 (NÀCÀC), 153.61 (OÀCÀC), 100.12 (ÀCH), 54.65 ppm (-CH -).
sitivity Tests, no. 4487, 1st ed., August 22, 2002.
2
ChemPlusChem 2016, 81, 1 – 5
3
ꢁ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
&
These are not the final page numbers! ÞÞ