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Environmental fate & pathways

Henry's Law constant

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Description of key information

Parent compound pivaloyl chloride (CAS 3282-30-2): From the water surface the substance will rapidly evaporate into the atmosphere.

Hydrolysis product pivalic acid (CAS 75-98-9): From the water surface the substance will not evaporate into the atmosphere.

However, as the parent compound rapidly hydrolyses in contact with water and forms pivalic acid (CAS 75-98-9), the assessment is predominantly based on the data for the hydrolysis product.

Key value for chemical safety assessment

Additional information

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.

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 pivaloyl chloride (CAS 3282-30-2) (Q)SAR results were used for the estimation of the Henry’s Law constant. 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 the Henry’s Law Constant are not provided.

 

Assessment

The parent compound pivaloyl chloride (CAS 3282-30-2) rapidly hydrolyses in contact with water and forms pivalic acid (CAS 75-98-9). Considering the Henry’s Law Constant, the assessment is therefore predominantly based on information available for the hydrolysis product pivalic acid.

 

Parent compound pivaloyl chloride:

No experimental data are available. Therefore, the Henry's Law constant (HLC) was calculated using the bond estimation method of HENRYWIN v3.20 (EPISuite v 4.11; BASF SE 2019). The model estimated the HLC of the substance to be 158 Pa*m³/mol. This estimate refers to the uncharged molecule. The substance is within the applicability domain of the model.

Results indicate a volatile character of the parent compound. However, pivaloyl chloride rapidly hydrolyses in contact with water to form pivaic acid. Therefore, this model calculation may be of low relevance.

 

Hydrolysis product pivalic acid:

In absence of experimental data, the Henry's Law constant (HLC) was calculated using the bond estimation method of HENRYWIN v3.20 (EPISuite v 4.11; BASF SE 2018). The model estimated the HLC of the substance to be 0.13 Pa*m³/mol. This estimate refers to the uncharged molecule. The substance is within the applicability domain of the model.

Based on the calculated data, the hydrolysis product pivalic acid (CAS 75-98-9) will not evaporate into the atmosphere from the water surface.

 

 

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