Registration Dossier
Registration Dossier
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EC number: 211-330-1 | CAS number: 638-29-9
Henry's Law constant
Administrative data
Link to relevant study record(s)
Description of key information
The hydrolysis product valeric acid will not evaporate into the atmosphere from the water surface.
Key value for chemical safety assessment
Additional information
Valeryl chloride (CAS 638 -29 -9) rapidly decomposes in water and forms HCl (CAS 7647 -01 -0) and valeric acid (CAS 109 -52 -4).
Due to this rapid hydrolysis, the assessment of the Henry's Law Constant of the parent compound is considered to be of low relevance. Therefore, the assessment of the HLC is based solely on the hydrolysis product valeric acid (CAS 109 -52 -4).
An experimental HLC value is availabe for valeric acid (CAS 109 -52 -4). In a publication of Khan and Brimblecombe (1992), the substance is reported to have a measured Henry's Law constant (HLC) of 0.048 Pa*m³/mol at 25 °C (cited in HENRYWIN v3.20, EPI Suite v4.11).
In addition, the HLC was calculated by two methods:
- using the bond estimation method of HENRYWIN v3.20 (EPISuite v 4.11; BASF SE 2020) the HLC was calculated to be 0.13 Pa*m³/mol. This estimation refers to the uncharged molecule. The substance is within the applicability domain of the model.
- using the VP/WS method, the HLC was calculated to be 0.111 Pa*m³/mol (BASF SE, 2020). According to Lyman (1985) this method is suitable for the prediction of the HLC, as the substance's water solubility is < 1mol/L.
The highest value (0.13 Pa*m³/mol, HENRYWIN v3.20) was used for the risk assessment.
In conclusion, based on a weight-of-evidence approach of the experimental and calculated data, valeric acid will not evaporate into the atmosphere from the water surface.
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