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EC number: 204-677-5 | CAS number: 124-07-2
Phototransformation in air
Administrative data
Link to relevant study record(s)
Description of key information
The calculated half-lives are in the range of 23.24 hours for hexanoic acid (C6) to 4.56 hours for docosanoic acid (C22).
Key value for chemical safety assessment
Additional information
No experimental data on photolysis in air are available for fatty acids. However comprehensive modeled data are provided in the OECD SIDS (2009) for aliphatic fatty acids of C6-C22 carbon chain length. In the EPISuite model a hydroxyl radical reaction of 1.5 * 106cm3hydroxyl radical concentration at 25 °C is assumed. The data show a decreasing photodegradation half-life with increasing chain length. Unsaturated fatty acids undergo photolysis faster than saturated. The half-life declines with the number of double bonds. The calculated half-lives of saturated fatty acids are in the range of 23.24 hours for hexanoic acid (C6) to 4.56 hours for docosanoic acid (C22).
Aliphatic Acid |
CAS Name |
Photodegradation in air [half-life] |
C6 |
Hexanoic acid CAS 142-62-1 |
23.236 hrs |
C8 |
Octanoic acid |
15.372 hrs |
C9 |
Nonanoic acid CAS 112-05-0 |
13.15 hrs |
C10 |
Decanoic acid |
11.485 hrs |
C12 |
Dodecanoic acid |
9.167 hrs |
C14 |
Tetradecanoic acid |
7.627 hrs |
C16 |
Hexadecanoic acid |
6.530 hrs |
C18 |
Octadecanoic acid |
5.710 hrs |
C18, 1 double bond |
9-Octadecenoic acid, (Z) |
1.544 - 1.699 hrs |
C18, 2 double |
9,12-Octadeca- |
0.892 - 0.998 hrs |
C22 |
Docosanoic acid |
4.562 hrs |
C22, 1 double |
13-Docosenoic acid, (Z)- |
1.446 - 1.581 hrs |
Data are cited from OECD SIDS Dossier “Aliphatic Acids Category”, 2009
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