Bis-oxadiazole

Bis-oxadiazole, or more formally known as bis(1,2,4-oxadiazole)bis(methylene) dinitrate, is a nitrated heterocyclic compound of the oxadiazole family.^[1]

Bis-oxadiazole

Names
Preferred IUPAC name [3,3′-Bi-1,2,4-oxadiazole]-5,5′-diylbis(methylene) dinitrate
Other names Bis(1,2,4-oxadiazole)bis(methylene) dinitrate Bis-isoxazole-bis-methylene dinitrate BIDN
Identifiers
3D model (JSmol)	Interactive image
PubChem CID	139033609
CompTox Dashboard (EPA)	DTXSID601336410
InChI InChI=1S/C6H4N6O8/c13-11(14)17-1-3-7-5(9-19-3)6-8-4(20-10-6)2-18-12(15)16/h1-2H2 Key: AVTVAJHPJUFZPZ-UHFFFAOYSA-N
SMILES [O-][N+](=O)OCC1=NC(=NO1)C1=NOC(CO[N+]([O-])=O)=N1
Properties
Chemical formula	C6H4N6O8
Molar mass	288.132 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Bis-oxadiazole is related to bis-isoxazole tetranitrate (BITN), which was developed at the United States Army Research Laboratory (ARL). With a high nitrogen content, these compounds are poised to release a large volume of very stable N₂.^[2] It is a “melt-cast” explosive material that is potentially both more powerful and environmentally friendly alternative to TNT.^[3]

Synthesis

Glyoxal condenses with hydroxylamine to yield diaminoglyoxime (DAG). Treating DAG with methyl glycolate [pt] in the presence of base at high temperature, followed by nitration, yields bis(1,2,4-oxadiazole).^[4]

Replacement for TNT

TNT is attractive explosive because it is a melt-castable. A low melting point of about 80 °C and high decomposition temperature of 295 °C allows manufacturers to safely pour TNT into molds. The production of TNT generates hazardous waste, e.g. red water and pink water.^[1]

Bis-oxadiazole, which is also melt-castable, is about 1.5 times more powerful than TNT and yet produces less hazardous wastes.^[1]

Physical Properties of Bis-oxadiazole Compared to TNT^[4]

Physical Property	bis-oxadiazole	TNT
Onset temperature of melting	84.5 °C	80.4 °C
Onset temperature of decomposition	183.4 °C	295.0 °C
Derived density from X-ray data	1.832 g cm−3	1.65 g cm−3
Detonation pressure	29.4 GPa	20.5 GPa
Detonation velocity	8180 m s−1	6950 m s−1
Molar enthalpy of formation	-79.4 kJ mol−1	-59.3 kJ mol−1

A major challenge in the production of bis-oxadiazole is its low yield.^[5]