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Environmental fate & pathways

Phototransformation in air

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Description of key information

The estimated KOH and t1/2 for NPEO using AopWin v1.92 program (EPIWEB v 4.0) were found to be 5.86 x10-11 cm3/molecule-sec and 0.189 days, respectively. There was no significant impact of branching of nonyl chains (isomers) on the phototransformation estimations.

Key value for chemical safety assessment

Half-life in air:
0.189 d
Degradation rate constant with OH radicals:
5.86 cm³ molecule-1 s-1

Additional information

The hydroxyl radical reaction half-life was estimated for NPEO using the AopWin v1.92 program of EPIWEB v 4.0 based on values for the individual constituents, calculated using default parameters of a 12 h day, a hydroxyl radical concentration of 1.5 × 106 molecules (radicals) /cm3 and a hydroxyl rate constant of 5.86 x10-11 cm3/molecule-sec. The final half-life for NPEO was then calculated on a weighted-average basis using the mole fractions of the individual constituents.

Hydroxyl radical reaction half-lives were also estimated for three typical isomers (due to branching) of nonyl chain of NPEO (e.g. 1, 2-dimethyl-1-ethyl-pentyl phenol E-2; 1, 3-dimethyl-1-propyl-butyl phenol E-2; 1-ethyl-1-methyl-hexyl phenol E-2). The KOH values ranged from 58.01 x 10-12 to 58.29 x 10-12 cm3/molecule-sec and the half-life ranged from 0.183-0.184 days. There was no significant impact of branching of nonyl chains (isomers) on the photo-transformation estimations.

The estimated KOH and t1/2 for NPEO using AopWin v1.92 were 5.86 x 10-11 cm3/ molecule-second and 0.189 days, respectively.