166 Synthetic Routes to AromaticC-Nitro Compounds
2,4,6-Tris(picrylamino)-1,3,5-trinitrobenzene (113), the product from condensing three
equivalents of aniline with 1,3,5-trichloro-2,4,6-trinitrobenzene followed by nitration with
mixed acid, is a high-molecular weight explosive which shows good thermal stability (m.p.
234 ◦C) but is readily detonated.^243
NO 2NO 2NO 2
NHNHNHNO 2NO 2NO 2O 2 N NO 2O 2 NO 2 N O^2 NO O^2 N
2 NNO 2NO 2NO 2N
H NNHN114
(PATO)NO 2NO 2N
H NNHN
N
HN
HN
N115
(BTATNB)113Figure 4.46High thermal stability is observed in explosives where the amino functionality is part of a
heterocyclic ring. A number of thermally stable explosives have been synthesized by condens-
ing polynitroarylene halides with triazole rings. 3-Picrylamino-1,2,4-triazole (PATO) (114) is
a thermally stable explosive (m.p. 310◦C, VOD∼7850 m/s,d= 1 .94 g/cm^3 ) conveniently
prepared from the reaction of picryl chloride with 3-amino-1,2,4-triazole.^244 Agrawal and
co-workers^245 prepared a similar compound known as BTATNB (115) from the reaction of
styphnyl chloride with two equivalents of 3-amino-1,2,4-triazole. Thermal and explosive per-
formance data suggests that BTATNB is slightly more thermally stable than PATO and safer
towards impact and friction. By following a similar strategy, Agrawal and co-workers reported
a number of explosives possessing a wide spectrum of properties.
H
NH
NNO 2O 2 N NO 2HNNNN NN
N NH117 (SAT)H
NNO 2O 2 N NO 2HNNNN116 (PAT)Figure 4.47Similarly, 5-picrylamino-1,2,3,4-tetrazole (PAT) (116)^246 ,^247 and 5,5′-styphnylamino-
1,2,3,4-tetrazole (SAT) (117)^247 have been synthesized by condensing picryl chloride and
styphnyl chloride with 5-amino-1,2,3,4-tetrazole in methanol respectively. A comparison of
thermal and explosive properties of newly synthesized PAT (calculated VOD∼8126 m/s) and
SAT (calculated VOD∼8602 m/s) reveals that PAT is more thermally stable than SAT but
more sensitive to impact and friction.^247
High molecular weight polynitroarylenes often show increased thermal stability. Thermal
stability is further enhanced when amino functionality is positioned adjacent to nitro groups.