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Environmental fate & pathways

Henry's Law constant

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Description of key information

From the water surface the substance will not evaporate into the atmosphere.

Key value for chemical safety assessment

Additional information

In water sodium acrylate will dissociate immediately into sodium- and acrylate-ions. Therefore, the estimation of the evaporation from the water surface into the atmosphere of sodium acrylate is based on acrylic acid. Henry's Law Constant of acrylic acid was calculated by Q(SAR) (SRC HENRYWIN v3.10) (BASF SE, 2008). The constant was estimated to be 0.029 Pa*m3/mol at 25 °C indicating that acrylic acid is essentially not volatile. Due to its pKa value of 4.0, the dissociated anionic form of acrylic acid is dominating under normal environmental conditions (pH range 5.5-9) as calculated by SPARC v4.2 (BASF SE 2009). Therefore, it has to be expected that the real partition of the total acrylic acid is determined only by its anionic form with a Henry's law constant being much lower than calculated above.


Thus, no evaporation of acrylic acid from the water surface into the atmosphere is expected under environmental conditions.