Environmental Engineering Reference
In-Depth Information
4.3.3.3 Preparation of Trinitromethane
Trinitromethane have two tautomers. The colorless nitro type tautomer is present in
an acidi
de; the yellow acid
type one is present in aqueous (without strong acid) or basic solution, pKa = 0.2.
The preparation of nitromethane at laboratory is the nitration of cyanide acid
with mixed acid at 10
ed solution and solution of diethyl ether or carbon disul
30
°
C to obtain trinitro acetonitrile, and then trinitromethane
-
after hydrolysis and acidi
cation. You can also obtain trinitromethane salt after
treatment of tetranitromethane with basic solution. In industry to produce trini-
tromethane catalyzed by mercuric nitrate, acetylene is nitrated with fuming nitric
acid, and the resulting trinitromethane is dissolved in excess nitric acid, then
concentrated sulfuric acid was added; trinitromethane is nitrated into tetranitrom-
ethane; because tetranitromethane is insoluble in acid mixture, trinitromethane and
tetranitromethane can be separated [
32
]. The separated liquid is treated with base to
generate trinitromethane salt, and trinitromethane can be produced after acidifi-
-
cation. Main reactions mechanism are:
HNO
3
CH
HC(NO
3
)
3
+ H
2
O
HC
C(NO
2
)
4
+ H
2
O
HC(NO
2
)
3
+ HNO
3
C(NO
2
)
4
+ 2KOH
KC(NO
2
)
3
+ KNO
3
+ H
2
O
KC(NO
2
)
3
+ H
HC(NO
2
)
3
+ K
The main side reaction is:
CNO
2
ð
Þ
4
þ
6KOH
!
4KNO
2
þ
K
2
CO
3
þ
3H
2
O
This method is relatively cumbersome, the yield is only about 40
50 % with a
−
purity of 99.9 %.
4.3.4 Properties and Preparation of Tetranitromethane
4.3.4.1 Properties of Tetranitromethane [
23
]
Formula: CN
4
O
8
NO
2
Structure:
O
2
N
C
NO
2
NO
2
Relative molecular weight: 196.03
Oxygen balance: 49.0 % (calculated according to the produced CO
2
)
Content of nitrogen: 29 %
Tetranitromethane (TNM) is a colorless to pale yellow oily liquid with odor
similar to nitrogen dioxide, the relative density of 1.6377, melting point of 14.2
C,
boiling point of 126
°
C and refractive index of 1.4382225. Tetranitromethane is
°
