Transformation products
The identification of transformation products involved those that had UV spectral and chro-
matographic properties identical to authentic standards. Aldehydes and ketonic intermediates
were identified as their 2,4-dinitrophenylhydrazones by high-performance liquid chromatogra-
pyruvic acid, glyoxal, and pyruvic aldehyde. The structures of these components are shown be-
low.
HOOC CH = O
CH3 CCOOH
CH3 C CH = O
O = CH CH = O
O
O
Glyoxylic acid
Pyruvic acid
Pyruvic aldehyde
Glyoxal
The chromatographic profile for 2-ADNT of the 2,4-dinitrophenylhydrazones appears in Figure 4.
There are still numerous products that have not been identified based on the lack of available
reference standards.
The 4-ADNT showed a similar set of carbonyl-containing products, but glyoxal was not ob-
served (Fig. 5). In place of glyoxal was another derivative that is believed to contain multiple
carbonyl-containing groups based on its chromatography and UV spectral properties (Fig. 6). It
appears that these products, although small in concentration, possess multifunctional carbonyl
moieties in their structures.
The formation (and decline) of the major known components for 2-ADNT and 4-ADNT are
shown in Figure 7 as a function of exposure time to ozone. The aldehyde and ketonic intermedi-
ates account for approximately 30% of the carbon material balance.
Carboxylic acids, chromatographed on the Supelcogel 610H column and detected at 210 nm,
36
0.12
32
2, 4-Dinitrophenylhydrazine
0.10
2, 4-Dinitrophenylhydrazine
28
0.08
24
Pyruvic
Acid
Glyoxylic
Acid
20
Glyoxylic
0.06
Acid
AU
AU
16
0.04
12
?
Pyruvic
8
Glyoxal
Pyruvic
Aldehyde
0.02
Aldehyde
Pyruvic
Acid
4
0
0
0
35
0
5
10
15
20
25
30
35
5
10
15
20
25
30
Time (min)
Time (min)
Figure 4. HPLC profile of carbonyl-containing
Figure 5. HPLC profile of carbonyl-containing
products from the ozonation of 2-ADNT.
products from the ozonation of 4-ADNT.
6
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