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Environmental fate & pathways

Phototransformation in air

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Description of key information

After evaporation or exposure to air, the substance will be rapidly degraded by photochemical processes.

Key value for chemical safety assessment

Half-life in air:
2.1 h
Degradation rate constant with OH radicals:
0 cm³ molecule-1 s-1

Additional information


 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 1-Ethylpiperazine (CAS 5308-25-8) (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.



Based on an estimated OH radical rate constant of 1.8059E-12 cm³/(molecule*sec), the half-life of 1-Ethylpiperazine (CAS 5308-25-8) was calculated to be 2.1 h (conditions: sensitizer for indirect photolysis: OH; 0.5 E06 OH/cm³, 24-h day) (BASF SE, 2018). The substance was within the applicability domain of the model; however, as the substance is a heterocyclic amine, the estimate may be highly uncertain (AOPWIN v1.92, EPI Suite v4.11, BASF SE, 2018).

Therefore, after evaporation or exposure to the air 1-Ethylpiperazine (CAS 5308-25-8) be rapidly degraded by photochemical processes.