Organic Chemistry of Explosives

The nitrolysis of hexamine 253

CH 2

N

NN

N

H 2 C CH 2

H 2 C CH 2

O 2 N NO 2

NO 2

4

(HMX)

N

NN

N

H 2 C CH 2

H 2 C CH 2

O 2 N NO 2

NO 2

CH 2 OAc

251

N

NN

N

H 2 C CH 2

H 2 C CH 2

O 2 N NO 2

NO 2

O 2 NO ONO 2

239

(DPT)

HNO 3 , Ac 2 O,

87 %

HNO 3 , N 2 O 5 ,

72 %

MeOH

93 %

HNO 3 , Ac 2 O

1 eq HNO 3 ,

excess Ac 2 O,

80 %

HNO 3 , Ac 2 O,

NH 4 NO 3 , 66 %

HNO 3 , Ac 2 O,

NH 4 NO 3

(see text)

HNO 3

98 %

AcOH,

NaOAc

70 %

57 %

OAc

248

NO 2 NO 2 NO 2

AcO N

NO 2

NNN

249

NO 2 NO 2 NO 2

N

NO 2

NNN

OMeMeO

250

NO 2 NO 2 NO 2

N

NO 2

NNN

Figure 5.111 The chemistry of DPT (239)

Treatment of DPT (239) with dinitrogen pentoxide in pure nitric acid leads to the isolation

of the nitrate ester (249), an unstable explosive which is highly sensitive to impact and readily

undergoes hydrolysis.^189 A low nitration temperature favours the formation of (249) and its

presence during the nitrolysis of hexamine is clearly undesirable. The nitrolysis of DPT (239)

with one equivalent of pure nitric acid in an excess of acetic anhydride yields 1-acetomethyl-

3,5,7-trinitro-1,3,5,7-tetraazacyclooctane (251),^189 a useful starting material for the synthesis

of other explosives.^189 ,^221

5.15.4.2 The chemistry of dimethylolnitramine

Dimethylolnitramine (252) is known to be present under the conditions of the Hale nitrolysis.

If the Hale nitrolysis reaction is quenched, the RDX removed by filtration and the aqueous

liquors neutralized to remove DPT, the remaining filtrate can be extracted into ether and that

solution evaporated over water to give an aqueous solution of dimethylolnitramine (252).^188

Dimethylolnitramine (252) readily participates in Mannich condensation reactions; treat-

ment of a aqueous solution of (252) with methylamine, ethylenediamine and Knudsen’s base

(254) (generated from fresh solutions of ammonia and formaldehyde) yields (253), (255) and

(239) (DPT) respectively.^188 The cyclic ether (258) is formed from the careful dehydration of

dimethylolnitramine (252) under vacuum.^188

Dimethylolnitramine (252) is inevitably present as its dinitrate ester (256) under the con-

ditions of hexamine nitrolysis. This compound is extremely sensitive to hydrolysis but can be