Organic Chemistry of Explosives

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9 Dinitrogen Pentoxide – An Eco-Friendly Nitrating Agent

9.1 Introduction

‘The majority of energetic materials (explosives, propellants etc.) are organic compounds

which derive their energy from the nitro (–NO 2 ) group. Thus the –NO 2 functionality is one

of the excellent characteristics of a molecule to be considered as an explosive and therefore,

nitrations or nitration reactions^1 have special place in the field of high energy materials.’^2 ,a

‘The nitro substituents are generally classified according to the nature of the atom to which

they are attached: carbon, nitrogen or oxygen.’^2 ,aAccordingly, in the previous chapters, the in-

troduction ofC-nitro,N-nitro (nitramine) andO-nitro (nitrate ester) functionality into organic

compounds has been discussed.

‘It has been usual practice to introduce such explosophoric groups in the structure of a

molecule with the use of conventional nitrating agents such as: absolute nitric acid, sulfuric

acid–nitric acid, acetic anhydride–nitric acid, ammonium nitrate–acetic anhydride-nitric acid

etc.’^2 ,a

‘A large number of explosive molecules have been reported in the literature using these

conventional nitrating agents and important examples are 2,4,6-trinitrotoluene (TNT), 1,3,5-

trinitro-1,3,5-triazacyclohexane (RDX), 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane (HMX)

and 2-nitro-1,2,4-triazol-5-one (NTO). Substantial progress has also been made in the synthe-

sis of thermally stable explosives such as 1,3-diamino-2,4,6-trinitrobenzene (DATB), 1,3,5-

triamino-2,4,6-trinitrobenzene (TATB), 3-picrylamino-1,2,4-triazole (PATO) and 1,3-bis(3-

amino-1,2,4-triazole)-2,4,6-trinitrobenzene (BATNB) etc. with these conventional nitrating

agents.’^2 ,a

‘However, problems associated with the use of these nitrating agents are manifold and

important among them are: (1) handling of nitrating agents on large scale, (2) low yields

coupled with formation of by-products, (3) maintenance/control of temperature because of the

exothermic nature of nitration reactions, (4) disposal of spent acids, and lastly (5) limited use

for the nitration of highly deactivated nitroaromatics.’^2 ,aOn an industrial scale, nitrations with

conventional nitric acid-based nitrating agents require strict control, including remote handling,

aReproduced by permission of Infomedia India Ltd., publisher ofChemical Worldmagazine.

Organic Chemistry of Explosives J. P. Agrawal and R. D. Hodgson

©C2007 John Wiley & Sons, Ltd.

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