Organic Chemistry of Explosives

326 N-Heterocycles

z-TACOT (225) and y-TACOT (231) are single isomers but their syntheses are rather long

for cost effective commercial manufacture. Industrially produced TACOT is a mixture of these

two isomers and the synthesis is much shorter and more convenient than the production of

the single isomers. In this synthesis benzotriazole is treated witho-nitrochlorobenzene to

produce an isomeric mixture of 1-(o-nitrophenyl)-2H-benzotriazole and 2-(o-nitrophenyl)-

2 H-benzotriazole, which on treatment with triethyl phosphite in refluxing xylene yields a

mixture of isomeric 1,3a,4,6a- and 1,3a,6,6a-dibenzotetraazapentalenes and nitration of this

mixture produces commercial TACOT. This mixture (VOD∼7250 m/s,d= 1 .64 g/cm^3 )

finds extensive use for applications where high temperature resistance is needed. TACOT is

available commercially in the form of flexible linear shaped charges (FLSC), plastic bonded

explosive (PBX), high-density charges and in mild detonating fuze. TACOT is also reported

to be used in the manufacture of high-temperature resistant detonators.

N

NH 2

NH 2 N

Cl

NO 2

N N

N

N

N

NO 2

N

N

NN

N

N

NO 2

NO 2

O 2 N

O 2 N

N

N

H

N

N

N

N

N

N

N

NO 2

N

N

NN

N

N N

NO 2

CI

N NH

N

N

232

239

NaNO 2 , AcOH

86 %

P(OEt) 3

xylene,

reflux

74 %

233

235

Na 2 CO 3 , DMSO,

80 °C, 51 %

236

Na 2 CO 3 , DMSO,

238 60 °C, 72 %

237

(aza-TACOT)

HNO 3 ,

H 2 SO 4

80 °C

58 %

(234)

P(OEt) 3 , xylene,

reflux, 60 %

Figure 7.82

The dipyridotetraazapentalene ring (236) also exhibits high thermal stability. The tetranitro-

derivative of this ring system, aza-TACOT (237), is synthesized by a similar route to that of

y-TACOT, but is more energetic than the latter.^139 ,^140

References

1. (a) J. P. Agrawal,Propell. Explos. Pyrotech., 2005, 30 , 316; (b) A. K. Sikder and N. Sikder,J. Haz.
   Mater., 2004,A112, 1; (c) G. S. Lee, A. R. Mitchell, P. F. Pagoria and R. D. Schmidt,Thermochim.
   Acta., 2002, 384 , 187; (d) J. P. Agrawal,Prog. Energy Combust. Sci., 1998, 24 , 1; (e) I. J. Dagley