Environmental Engineering Reference
In-Depth Information
diluted mineral acid and primary nitroalkane or secondary nitroalkane can react as
the following Nef reaction [
7
].
O
+2NaHSO
4
+N
2
O+H
2
O
2RCH
2R-CH=NOONa+2H
2
SO
4
R'
R
R'
R
2
NOONa
+2H
2
SO
4
2
C
O
+2NaHSO
4
+N
2
O+H
2
O
C
The yield of Nef reaction is generally up to 85 % (except for nitromethane). If
the steric hindrance of this reaction is relatively large, the yield will be decreased
signi
cantly.
Primary and secondary nitroalkane react with nitrous acid, in which
α
-hydrogen
atoms will be substituted.
NO
RCH
2
NO
2
+HNO
2
RCH
+H
2
O
RC
NO
2
NOH
NO
2
Nitrosates
1-nitroso-Nitroparaffin
NO
NO
2
+H
2
O
Pseudonitrol
The neutralization of nitrolic acid and will generate crimson salt. Pseudonitrol
from the reaction between nitrous acid and secondary nitroalkane does not have
R
2
CHNO
2
+HNO
2
R
2
C
-
hydrogen atoms, cannot be rearranged and also have no color development reac-
tion, which could be used to distinguish primary and secondary nitroalkanes.
Nitric acid (70 %) or the mixture of nitric acid and sulfuric acid or other mixed
acids with catalytic function can nitrate secondary nitroalkanes directly into gem-
inal dinitroalkane [
8
]. With the sodium alkoxide and tetranitromethane, primary
nitroalkanes can be nitrated into dinitroalkanes and trinitroalkanes [
9
]. In a neutral
or basic solvent, primary, secondary nitroalkane salts can be nitrated, step by step,
into gem-dinitroalkanes by silver nitrate and sodium nitrite [
10
]. Alkali metal salts
of aryl nitroalkanes can be nitrated, step by step, into dinitroalkanes and trinitro-
alkanes by dinitrogen tetroxide [
11
].
(3) Reaction with Base
Both nitroalkane and aromatic nitro compounds can react with bases to produce
salts. Primary nitroalkane reacts with concentrated NaOH to generate trialkyl is-
oxazole [
12
].
α
