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Environmental fate & pathways

Henry's Law constant

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Description of key information

From the water surface propionic acid will not evaporate into the atmosphere. 

Key value for chemical safety assessment

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

Additional information

The Henrys Law Constant was calculated as 0.07 Pa*m3/mol for the uncharged molecule. Due to the fact that the test substance is an acid, the Henry Law Constant has to be recalculated for the environmentally relevant pH values (5 to 9). This calculation may be performed by using the correction formula: CORR = 1/(1 + 10^(A*(pH-pKa))

The resulting HLCs were pH 5 = 0.03 Pa*m3/mol, pH 7 = 0 Pa*m3/mol and pH 9 = 0 Pa*m3/mol

Based on these recalculated HLCs propionic acid does not evaporate into the atmosphere from the water surface.