Organic Chemistry of Explosives

Addition and condensation reactions 45

Formaldehyde is the most important aldehyde used in Henry reactions in relation to ener-

getic materials synthesis. Nitroform (112) reacts with formaldehyde in the form of trioxane

or formalin to yield 2,2,2-trinitroethanol (159).^298 ,^299 The Henry reaction of nitroform with

aldehydes other than formaldehyde gives products which are not isolable.

FC(NO 2 ) 3 + CH 2 O FCHC 2 OH

NO 2

NO 2

MeOH, NaOH

-10 °C, 91 %

119

98

Figure 1.80

2-Fluoro-2,2-dinitroethanol (119) is rarely synthesized from fluorodinitromethane but is re-

portedly synthesized at Rockwell International, Rocketdyne Division in large quantities from

the reaction of fluorotrinitromethane (98) with an alkaline solution of formalin.^300 The same re-

action with alkaline hydrogen peroxide and formalin is also used for 2-fluoro-2,2-dinitroethanol

production.^239 Unlike nitroform, fluorodinitromethane forms stable products with aldehydes

other than formaldehyde.^301 −^305 Products obtained from the reaction of fluorodinitromethane

with dialdehydes contain two hydroxy groups and may find use for the synthesis of energetic

polymers.^303 −^305

CF(NO 2 ) 2 CH (CH 2 )n CHCF(NO 2 ) 2

OH OH

n = 1–5, 48 % -- 78 %

(ref. 303--306)

OHC(CH 2 )nCHO + F(NO 2 ) 2 CH

H 2 O, pH 6.5 - 7.0

Figure 1.81

Both the Henry reaction and the reverse demethylolation are synthetically useful in the

chemistry of polynitroaliphatic compounds. The Henry reaction is commonly used to mask

the natural chemistry of an aliphatic nitro or terminalgem-dinitro group by removing the

acidicα-proton(s). In Section 1.7 we discussed the conversion ofα,ω-dinitroalkanes to their

bis-methylol derivatives before subjecting them to oxidative nitration and subsequent demethy-

lolation with base, a procedure which results in the formation ofα,α,ω,ω-tetranitroalkanes.^108

CH 2 OH

HC O 2 N CNO 2

NO 2 K

NO 2

HOCH 2 C

2 CH KOH, 99 % NO^2 K

2 O, AcOH

66 %

+ CH 2 O

18

CH 2 OH

19

NO 2

20

KOH, H 2 O 2 , Heat

AcOH, CH 2 O

−CH

2 O

76 %

Figure 1.82

Many of the nitronate salts of polynitroaliphatic compounds, particularly salts ofgem-

nitronitronates, exhibit properties similar to known primary explosives. Consequently, the

storage of such salts is highly dangerous. Treatment of these nitronate salts with formaldehyde

yields the corresponding methylol derivative via the Henry condensation. These methylol