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Environmental fate & pathways

Henry's Law constant

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Description of key information

Key value for chemical safety assessment

Henry's law constant (H) (in Pa m³/mol):
0.003
at the temperature of:
20 °C

Additional information

The Henry’s law constant (HLC) of NPEO was estimated by HENRYWIN v3.20 ( (EPIWEB v 4.0) using the bond and group contribution methods, based on HLC values for the individual components of the substance. Since the estimates by the bond and group methods were not different, the values were averaged. The HLC for NPEO was finally calculated on a weighted-average basis using the mole fractions of the individual components. The HLC were also estimated for three typical isomers (due to branching) of the nonyl chain of NPEO (i.e. 1, 2-dimethyl-1-ethyl-pentyl phenol EO-2; 1,3-dimethyl-1-propyl-butyl phenol EO-2; 1-ethyl-1-methyl-hexyl phenol E-2). There were only minor differences in the results obtained, with values ranging from 2.16 x 10-9 to 2.3 x 10-9 atm-m3/mole. The average estimated HLC for NPEO was 3.21 x 10-7 atm-m3/mole (3.25 x 10-2 Pa-m3/mole). There was no significant impact of branching of nonyl chains (isomers) on the HLC estimation.