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ALIPHATIC NITRO COMPOUNDS^389

Nicholson found the following vapour pressures for temperatures ranging from

0°C to 40°C:
Temperature, °C 0 13.8 20 30 40
Vapour pressure, mm Hg 1.9 5.7 8.4 14.9 25.8
Changes in the vapour pressure of tetranitromethane depending on temperature

may be expressed by a first degree equation:

log p = 8.63-2260/T

From the above data Nicholson has calculated the latent heat of evaporation

10.3 kcal/mole. Edwards has given the following figures for temperatures ranging

from 40°C to 100°C

Temperature, °C 40 50 60 70 80 90 100

Vapour pressure, mm Hg 26.5 43.3 68.0 108.0 164.0 239.0 339.6

He has presented changes in vapour pressures as a variable dependent on tem-

perature, according to the equation:

log p = 7.23-2130/T

and has calculated the latent heat of evaporation to be 9.7 kcal/mole.

CHEMICAL PROPERTIES

Although tetranitromethane does not contain active hydrogen it readily enters

certain reactions. With water it reacts slowly to form trinitromethane, i.e. nitro-

form:

C(NO 2 ) 4 + HOH -> CH(NO 2 ) 3 + HNO 3 (20)

With potassium hydroxide, tetranitromethane readily yields its potassium salt

of nitroform :

C(NO 2 ) 4 + 2KOH + CK(NO 2 ) 3 + KNO 3 + H 2 O (21)

It react with sodium sulphite to yield sodium trinitromethanesulphonate

C(NO 2 ) 4 + NO 2 SO 3 -> (O 2 N) 3 CSO 3 Na + NaNO 2 (22)

With copper or nickel in the presence of ammonia it forms complex salts having

initiating properties (Vol. III).

Tetranitromethane is added to compounds having double bonds to form brown

or yellow products. The reaction is very sensitive and may be utilized, for example,

for detecting traces of olefins in paraffin fractions (Werner [56]).

Tetranitromethane reacts with tertiary amines, causing their degradation with

the formation of N-nitroso derivatives of secondary amines. In this way tertiary

amines may be converted to secondary ones (E. Schmidt and co-workers [57, 58]):

(R.CH 2 ) 3 N + C(NO 2 ) 4 -> (R.CH 2 ) 2 N.NO + R.CHO + CH(NO 2 ) 3

HCI OH- (23)

(RCH 2 ) 2 NH 2 Cl: -> (R.CH 2 ) 2 NH