Registration Dossier
Registration Dossier
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EC number: 209-750-5 | CAS number: 592-34-7
Phototransformation in air
Administrative data
Link to relevant study record(s)
Description of key information
After evaporation or exposure to the air, the substance will be slowly degraded by photochemical processes.
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 the substance (Q)SAR results were used for phototransformation in air (hydroxyl radical reaction). 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.
Assessment
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 4.5673E-12 cm³/(molecule*sec), the half-life was calculated to be 84.31 h; for this calculation a 24 -hour day as well as a sensitizer-concentration (OH-radicals) of 500,000 molecules/cm³ were assumed (BASF SE, 2017). The result is falling into the applicability domain of the model.
Due to the rapid hydrolyse of butyl chloroformate (CAS 592 -34 -7) the assessment was supported by read-across of the metabolite butanol (CAS 71 -36 -3). The phototransformation in air was also calculated with AOPWIN v1.92, implemented in EPISuite v4.11. Based on an estimated OH radical rate constant of 6.89E-12 cm³/(molecule*sec), the half-life was calculated to be 55.89 h; for this calculation a 24 -hour day as well as a sensitizer-concentration (OH-radicals) of 500,000 molecules/cm³ were assumed (BASF SE, 2017). The result is falling into the applicability domain of the model.
As butyl chloroformate has a vapour pressure of <1000 Pa and the cut-off time for reaching the stratosphere is 2 days, the substance is considered to have potential for reaching the stratosphere and/or long-range atmospheric transport. This assessment refers to dry air. In mist, rain, droplets and aerosols, hydrolysis will be the major fate process due to the short half-life in aqueous environments. Therefore assessment of the parent substance may be of low relevance.
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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