Organic Chemistry of Explosives

Chemical stability of polynitroaliphatic compounds 53

Table 1.12 Reactions of nitroalkanes and polynitroalkanes

with alkali base

Nitroalkane Product

C(NO 2 ) 4 M+C(NO 2 ) 3

HC(NO 2 ) 3 M+C(NO 2 ) 3

RCH 2 NO 2 Nitronate salt

R^1 R^2 CHNO 2 Nitronate salt

RCH(NO 2 ) 2 Nitronate salt

R^1 R^2 C(NO 2 ) 2 No reaction

R^1 R^2 CHC(NO 2 ) 3 R^1 R^2 CHC(NO 2 )− 2 M+

treatment with both base and nucleophile. In fact, treatment of tetranitromethane with alkali

hydroxides or aqueous ammonia provides a convenient route to nitroform salts.^354 This elec-

tron deficiency of the nitro groups in tetranitromethane finds use in the alkaline nitration of

compounds with active methylene groups.^179 The point is further illustrated by the slow de-

composition of tetranitromethane in the presence of water, giving nitroform and nitric acid

as products. Trinitromethyl groups will also slowly decompose in the presence of hot water.

A summary of the reactions of nitroalkanes and polynitroalkanes with alkali base is given in

Table 1.12.

CH 3 C

NO 2

24

NO 2 NO 2 K

C

NO 2

33

CH 3 NO 2

KI, 81 %

or KOH, H 2 O 2

100 %

Figure 1.94

As discussed above, the nitro groups of tetranitromethane and trinitromethyl compounds

are susceptible to nucleophilic attack. Both potassium iodide^355 and alkaline hydrogen

peroxide^356 affect the reductive denitration of trinitromethyl groups togem-nitronitronates;

1,1,1-trinitroethane (33) is quantitatively reduced to potassium 1,1-dinitroethane (24) on treat-

ment with alkaline hydrogen peroxide.^356 Nucleophiles such as potassium fluoride in DMF can

displace nitrite anion from tetranitromethane.^357 ,^358 Various nucleophiles, including azide,^359

chloride,^358 fluoride^359 and ethoxide^359 have been used to displace one of the nitro groups from

fluorotrinitromethane.

C

NO 2

NO 2

NO 2 C

NO 2

NO 2

C OEt

NO 2

NO 2

NaN 3 , DMF

-15 to 20 °C

35 %

-10 to 10 °C

74 %

NaOEt, CH 2 Cl 2

F N 3 F F

Figure 1.95

The carbon–halogen bonds of 1-halo-1,1-dinitroaliphatic compounds are particularly elec-

tron deficient and susceptible to nucleophilic attack. This kind of reaction is synthetically

useful in the chemistry of terminalgem-dinitroaliphatic compounds. Somegem-nitronitronate