urbaf2

ALIPHATIC NITRO COMPOUNDS 595

Besides 1,2-dinitroethane a nitrous ester (nitroethyl nitrite) is also formed which

is unstable and may decompose. According to N. Levy et al., nitroethyl nitrite

may be hydrolysed by dissolving the reaction mixture in methyl alcohol. Dini-

troethane then precipitates as a crystalline mass.

Nitration is always accompanied by the oxidation of the olefin (Baldock,

N. Levy and Scaife [77]).

Dinitroethane is a very powerful explosive, giving a lead block expansion of

140-150 (picric acid = 100). Its density is 1.46. It is less sensitive to impact than

picric acid. Since it is highly reactive, and hence unstable, it has not found any use

as explosive. It reacts most readily with bases. For example, when stored in a glass

vessel it decomposes after a few weeks as the result of its contact with glass, which

has basic properties. Levy suggests adding to the product an organic acid, as for

example p- toluenesulphonic acid, as a stabilizer. Under the influence of bases

dinitroethane may form nitroethylene, as well as other less defined products, which

can readily polymerize to form resinous substances.

1,1-DINITROETHANE

CH 3 CH(NO 2 ) 2

m. p. 37.5°C, b. p. 185°C

This substance was obtained by ter Meer [78] by acting with sodium nitrite

on 1-bromo-1-nitroethane:

(27)

It can also be obtained by oxidation of nitrolic acid derived from nitroethane

(Topchiyev [79]) :

(28)

Chancel [80a] described another general method of preparing 1,1-dinitroparaf-

fins and in particular 1,1-dinitroethane, starting from ethyl acetoacetate and its deriv-
atives :

CH 3 COCH(R)COOC 2 H 5 HNO^3 > R-CH(NO 2 ) 2 + CH 3 COOH + CO 2 + C 2 H 5 ONO 2

The yield of the reaction is relatively low (5-6%).

Recently Novikov [81] prepared 1,1-dinitroethane using this method.

A new excellent method of preparing gem-dinitroparaffins was recently reported

by Kaplan and Shechter [97]. It consist in acting with AgNO 3 + NaNO 2 on sodium

salts of nitroparaffins.
This substance has been suggested as monofuel for rocket propulsion (Wood [82]).