Registration Dossier

Diss Factsheets

Environmental fate & pathways

Phototransformation in air

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

After evaporation or exposure to the air, acid chlorides, coco and its hydrolysis products will be rapidly to moderately degraded by photochemical processes.

Key value for chemical safety assessment

Additional information

The photodegradation potential of the parent substances is regarded to be of low relevance due to the rapid hydrolysis of the acid chlorides in aqueous solution. In mist, rain, droplets and aerosols, hydrolysis will be the major fate process. Therefore the assessment is based on the corresponding acids as their hydrolysis products.

Photodegradation potential estimated with AOPWIN v1.92 (0.5 E06 OH/cm³, 24h day)

Hydrolysis

product

CAS no.

Rate constant

DT50

cm³/molecules*s

h

d

Octanoic acid

124-07-2

8.3499E-12

46.1

1.9

Decanoic acid

334-48-5

11.1760E-12

34.5

1.4

Lauric acid / Dodecanoic acid

143-07-7

14.0021E-12

27.5

1.1

Myristic acid / Tetradecanoic acid

544-63-8

16.8282E-12

22.8

0.95

Palmitic acid / Hexadecanoic acid

57-10-3

19.6543E-12

19.6

0.82

Stearic acid / Octadecanoic acid

57-11-4

22.4804E-12

17.1

0.71

Based on a 24 -h day and an OH-radical concentration of 0.5 E06 OH/cm³, the degradation rate constant for the six hydrolysis products varies between 8.35E-12 and 22.5E-12 cm³/(molecule*sec). Following this the substances are expected to be photodegraded by OH-radicals with a half-life of 0.7-1.9 days (BASF, 2012).

It can be concluded that acid chlorides, coco and its hydrolysis products will be rapidly to moderately degraded by photochemical processes after evaporation or exposure to air.