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Environmental fate & pathways

Phototransformation in air

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Description of key information

Parent compound valeryl chloride and hydrolysis product valeric acid: After evaporation or exposure to air, the substance will be slowly degraded by photochemical processes. 

This estimation refers to dry air. In mist, rain, droplets and aerosols, hydrolysis will be the major fate process of the acid chloride due to the short half-life in aqueous solution. Therefore this estimate may be of low relevance.

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 valeryl chloride (CAS 638 -29 -9) (Q)SAR results were used for phototransformation in air.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 phototransformation in air are not provided.

Parent compound valeryl chloride:

The phototransformation in air was assessed by a QSAR calculation with AOPWIN v1.92, implemented in EPISuite v4.11. Based on an estimated OH radical rate constant of 5.8735 E-12 cm3/(molecule*sec), the half-life of valeryl chloride was calculated to be 2.7 days (conditions: sensitiser for indirect photolysis: OH; 0.5 E06 OH/cm3, 24-h d; BASF SE, 2020). The substance is within the applicability domain of the model. Based on the EPI Suite calculation the substance will be slowly degraded by photochemical processes after evaporation or exposure to air.

This estimation refers to dry air. In mist, rain, droplets and aerosols, hydrolysis will be the major fate process of the acid chloride due to the short half-life in aqueous solution. Therefore this estimate may be of low relevance for valeryl chloride.

Hydrolysis product valeric acid:

The phototransformation in air was assessed by a QSAR calculation with AOPWIN v1.92, implemented in EPISuite v4.11. Based on an estimated OH-radical rate constant of 4.1108 E-12 cm3/(molecule*sec), a half-life of 3.9 days was calculated for the photochemical degradation by OH-radicals (conditions: sensitiser for indirect photolysis: OH, 0.5 E06 OH/cm³, 24-h d; BASF SE, 2020). The substance is within the applicability domain of the model.

Based on the EPI Suite calculation the substance will be slowly degraded by photochemical processes after evaporation or exposure to air.