Environmental Engineering Reference
In-Depth Information
Table 5.5
UV absorption parameters of nitrate esters [
7
,
8
]
Compounds
Solvent
Maximum absorption
Wavelength
(nm)
Absorptivity
(
ʵ
)
C
2
H
5
ONO
2
270
10
-
C
2
H
5
ONO
2
Ethanol
265
14.8
ʱ
-methylglucose-6-nitrate esters
Water
265
19.0
2,3,4-trimethyl-
ʱ
-methylglucose-6-nitrate
Ethanol
265
21.4
esters
621 cm
1
Asymmetric stretching
m
as
NO
2
ð
Þ
1
;
675
1
;
268 cm
1
Symmetric stretching
m
a
NO
2
ð
Þ
1
;
301
1
;
950 cm
1
Stretching
ð
C
O
Þ
1
;
100
m
816 cm
1
Stretching
ð
O
N
Þ
880
m
737 cm
1
Vibrating
c
w
NO
2
ð
Þ
760
640 cm
1
Bending
d
ð
NO
2
Þ
710
580 cm
1
Sway
c
r
NO
2
ð
Þ
ONO
2
molecular was substituted, the frequency of the asymmetric
vibration of NO
2
would be changed. The frequency of
If R in R
-
ν
as
(NO
2
) would be decreased
or increased by the positive or negative induction effect of R group. It can be used
to discriminate primary, secondary, and tertiary alkyl nitrate.
If
ONO
2
group is close to other big groups, the asymmetric and symmetric
bands of NO
2
group will be blue shifted. Optical isomerism can be distinguished by
this phenomenon. Because of the optical isomerism, both stretching vibrations of
NO
2
group will be split to two distorted peaks
-
25 cm
1
Asymmetric
1
35 cm
1
Symmetric
10
There are intramolecular hydrogen bonds, which cannot be detected by instru-
ment, between OH and ONO
2
groups. It might be because ONO
2
restrains the
formation of intermolecular hydrogen bonds with OH groups.
