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EC number: 203-851-8 | CAS number: 111-26-2
Henry's Law constant
Administrative data
Link to relevant study record(s)
Description of key information
The substance will not evaporate into the atmosphere from the water surface.
Key value for chemical safety assessment
- Henry's law constant (H) (in Pa m³/mol):
- 2.73
- at the temperature of:
- 25 °C
Additional information
In a publication (Christie and Crisp 1967) the activity coefficients of n-primary, secondary and tertiary aliphatic amines were reported. Using a modification of the air-bubbling method of Shaw & Butler the partial vapour pressures of the amines in solution were determined at 25 °C. The Henrys Law constant was calculated based on the molar fraction and the partial pressure of the amine.
The Henrys Law constant was of the uncharged molecule was calculated to be 2.73 Pa*m3 / mol at 25 °C.
In addition the Henrys Law constant was calculated using US EPA EPISuite software. The Henrys Law constant was calculated to be 3.17 Pa*m3 / mol at 25 °C. The substance is within the applicability domain of the model. Thus, the result was regarded as reliable. Furthermore the Henrys Law constant was calculated based on the vapour pressure and the water solubility of the test item. The water solubility of the test item is below 1 mol/L and is therefore within the applicability domain of the model. The Henrys Law constant was calculated to be 8.94 Pa* m3/mol at 25 °C.
According to the REACH Guidance Document R7a, Appendix R.7.1-2 pH correction of partition coefficients for ionisable substances, p. 189, May 2008 the Henrys Law constant of the uncharged molecule was corrected for ionisable substance. Based on the result of Christie and Crisp 1967 the Henrys Law constant for the charged molecule at 25 °C was calculated to be 0.00000543 Pa*m3 / mol at pH = 5, 0.000543 Pa*m3 / mol at pH = 7 and 0.0543 Pa*m3 / mol at pH = 9 respectively.
All reported values are in the same range. A Henrys Law constant of 2.73 2.73 Pa*m3 / mol at 25°C for the uncharged molecule was regarded as most reliable and was therefore chosen as key value for chemical safety assessment. Based on the criteria of OECD TG 23 as the Henrys Law constant is below 100 Pa*m3/mol the substance was considered not to significantly evaporate into the atmosphere from the water surface.
QSAR-disclaimer
In Article 13 of Regulation (EC) No 1907/2006, it is laid down that information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI (of the same Regulation) are met. Furthermore according to Article 25 of the same Regulation testing on vertebrate animals shall be undertaken only as a last resort.
According to Annex XI of Regulation (EC) No 1907/2006 (Q)SAR results can be used if (1) the scientific validity of the (Q)SAR model has been established, (2) the substance falls within the applicability domain of the (Q)SAR model, (3) the results are adequate for the purpose of classification and labeling and/or risk assessment and (4) adequate and reliable documentation of the applied method is provided.
For the assessment of N-HEXYLAMINE (Q)SAR results were used for Henrys Law Constant (HLC) The criteria listed in Annex XI of Regulation (EC) No 1907/2006 are considered to be adequately fulfilled and therefore the endpoint(s) sufficiently covered and suitable for risk assessment.
Therefore, further experimental studies on Henrys Law Constant (HLC)are not provided.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
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