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Environmental fate & pathways

Henry's Law constant

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Description of key information

Henry's Law Constant: Calculated HLC for the registration substance at environmental temperature (12°C): 8.8E-07 Pa m3/mol

Key value for chemical safety assessment

Henry's law constant (H) (in Pa m³/mol):
at the temperature of:
12 °C

Additional information

The transfer of a substance from the water phase to the gas phase can be estimated by means of the Henry’s Law Constant (HLC). No measured value for this parameter is available.

For the registration substance, the water solubility limit and vapour pressure cannot be validated accurately due to being extremely low values and outside the normal range. The HLC can be estimated using the established Bond method from HENRYWIN v. 3.20 within the EPIWeb suite v4.11. This method derives the Henry's Law Constant directly from the structure, as the sum of the bond contribution values for each chemical bond in the molecule. The bond contribution values were determined based on least-square regression analysis of measured HLCs for organic compounds.

The calculated HLC value for octaphenylcyclotetrasiloxane at 25°C is very low, 1.8E-06 Pa m3mol-1 (HenryWin v 3.20).