Environmental Engineering Reference
In-Depth Information
AgNO
3
.NaNO
2
NaOH.HCHO
CH
3
CH
2
NO
2
CH
3
CH(NO
2
)CH
2
OH
CH
3
C(NO
2
)
2
CH
2
OH
DPNOH
In the company Aerojet, based on the TerMeer method [
37
], DNPOH was
synthesized from as the starting material nitroethane in dichloroethane (EDC),
through the chlori
cation with sodium chloride, substitution of chlorine atom with
nitro, and finally reaction with formaldehyde under the action of sulfuric acid. The
reaction mechanism is:
NaOH.NaNO
2
EDC
1.NaOH.EDC
2.Cl
2
CH
3
CHClNO
2
CH
3
CH
2
NO
2
H
2
SO
4
.H
2
O.HCHO
EDC
CH
3
C(NO
2
)=NO
2
Na
CH
3
C(NO
2
)
2
CH
2
OH
Wright et al. used silver as a medium to electrolyze and oxidize salts of polynitro
compounds to prepare gem-polynitroalkanes [
64
]. The reaction mechanism is:
R-NO
2
+Ag
þ
!
RC-NO
2
+Ag
RC-NO
2
+NO
2
!
RC-(NO
2
Þ
2
RC-(NO
2
Þ
2
+Ag
þ
!
RC-(NO
2
Þ
2
+Ag
The electrolytic oxidation of silver electrode generate silver ions, which then
react with nitrite and nitroethane to produce 1,1-dinitroethane and metal silver. The
initial electron transfer reaction stage is a free radical ions generating from nitro-
alkanes, and nitrite attacks free radical to generate polynitro intermediate which is
oxidized to the gem-dinitro compound; after the continuing electrolysis, a small
amount of silver is produce on the bottom of electrolysis groove, and a certain
consumption of the silver electrode can also be found.
The advantage of chlorination nitri
cation process is the low raw materials cost,
which is suitable for continuous production and mass production, but the yield of
the synthesized BDNPF/A is low with relatively large amount of impurities, and the
production process is relatively complex; the advantage of oxidation nitration is the
synthesized BDNPF has high yield and high purity, which is suitable for batch
operation, the production process has been effectively controlled and simpli
ed, but
the cost of production process with silver nitrate, low chlorine content and sodium
hydroxide is signi
cantly high [
39
]. According to the raw material costs, equipment
costs, operating costs, labor costs and other factors, chlorination nitration is suitable
for the industrial continuous production, while oxidation nitration method is suit-
able for the batch preparation of a small amount of high-purity products. Electro-
lytic production of DNPOH silver is mainly used in laboratory research and not
suitable for industrial production because the required consumption of silver.
In Ter Meer method, due to the use of chlorine and a large amount of chlorinated
solvents, a large amount of waste will be generate from the production process,
which has heavy pollution on environment. Additionally, there are many problems
