Organic Chemistry of Explosives

284 Nitramines and Their Derivatives

N-Nitration of the amine (139) with mixed acid yields the energetic nitramine (140).^59

The same reaction with sodium nitrite in sulfuric acid, or with nitrosyl fluoride in methylene

chloride, yields the nitrosamine (141), which is also an energetic high explosive.^60

H 2 NCH 2 CH 2 NH 2

+

NO 2

2 N CO

NO 2

142

NO 2

2 N CO

NO 2

143

2

HNO 3 ,

Ac 2 O

2

CH 2 OH

CH 2 NHCH 2

NO 2 NO 2

2 N CO

NO 2

144

CH 2 N CH 2

Figure 6.43

The trinitromethyl group is often incorporated into explosive molecules to increase oxygen

balance. In fact, the six oxygen atoms present in the trinitromethyl group often give rise to

a positive oxygen balance. The energetic nitramine (144) is an example of an explosive with

an excellent oxygen balance.^61 N-Nitro-N′-(2,2,2-trinitroethyl)guanidine (TNENG) (145) has

been prepared^62 from the reaction of nitroguanidine, formaldehyde and nitroform. TNENG

has attracted interest as a burn rate accelerator in energetic propellants, the trigger for its

decomposition being the trinitromethyl group.

145

(TNENG)

NH

O 2 NHN NHCH 2 C(NO 2 ) 3

N

CH 2 C(NO 2 ) 2 NF 2

CH 2 C(NO 2 ) 2 NF 2

146

(DFAP)

O 2 N

Figure 6.44

DFAP (146) is a high-energy material with potential as an oxidizer in energetic propellants.

DFAP has been prepared from the reaction of bis(2,2-dinitroethyl)nitramine with NF 2 OSO 2 F.^63

A number of energetic heterocycles containing both furazan and nitramine functionality

have been reported – these are discussed in Section 7.3.4. There are many other examples of

compounds containing nitramino functionality in conjunction with other explosophores. These

are too numerous to discuss fully in this text. Many of these compounds are discussed in three

major reviews.^64 −^66

6.11 Energetic groups

6.11.1 Dinitramide anion

The dinitramide anion (147) was first synthesized^67 −^73 at the Zelinsky Institute in Russia

in 1971 and is one of the most significant discoveries in the field of energetic materials.

Ammonium dinitramide (ADN) has attracted particular interest as a chlorine free, and hence,

environmentally friendly alternative to ammonium perchlorate in composite propellants. The

absence of carbon and chlorine in its structure reduces the radar signature in the exhaust plume

of ADN-based propellants in rockets/missiles. The amount of ‘free oxygen’ in ammonium

dinitramide is also high, allowing for formulations with powerful reducing agents like alu-

minium and boron.