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Environmental fate & pathways

Henry's Law constant

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Description of key information

Group Method approach by EPIWIN: 1.84 Pa*m³/mol at 25 °C (Chemservice S.A., 2010). 
pH corrected values were calculated according to ECHA Guidance R.7a: 3.43 E-7 Pa*m³/mol (pH4), 3.43 E-6 Pa*m³/mol (pH 5), 3.43 E-4 Pa*m³/mol (pH 7) and 3.36 E-2 Pa*m³/mol (pH 9) (BASF SE, 2012)

Key value for chemical safety assessment

Henry's law constant (H) (in Pa m³/mol):
0
at the temperature of:
25 °C

Additional information

No experimental data concerning the Henry´s Law constant is available for dimethylamine. Therefore, the distribution of the substance between aqueous solutions and air was determined by calculation. For this purpose the computer program from US-EPA (EPIWIN, software HENRYWINv3.20) was used. Using the Bond method a constant of 1.69 Pa*m³/mol was calculated. The Group method gives a result of 1.84 Pa*m³/mol and is taken as key value for the chemical safety assessment. Both values are calculated for an ambient temperature of 25 °C.

The calculated values are representative for the uncharged molecule. At environmental conditions the molecule is expected to be ionised, therefore a pH-corrected HLC was calculated according to the REACH Guidance document (2008). The resulting Henry´s Law constant was 3.43 E-4 Pa*m³/mol at pH 7 (BASF, 2012). Based on the pH-corrected HLC, the substance will not evaporate from the water surface into the atmosphere.