Registration Dossier
Registration Dossier
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EC number: 270-128-1 | CAS number: 68411-46-1
Endpoint summary
Administrative data
Description of key information
Additional information
If released into water, the UVCB substance can be expected to be poorly biodegradable based on experimental data (OECD 301B). The diphenylamine (DPA) core of the substance is not readily biodegradable. Multiple branched alkyl chains are known to degrade slowly. It is considered that for most isomers (in the focus are those carrying an alkyl chain on both rings of DPA) a fast biodegradation of the DPA core is hindered or impeded for sterical reasons and that biodegradation along the branched alkyl chains is slow. Overall, although biodegradation is expected to occur in the water-soluble fraction, the biodegradation rate is expected to be too small to go below the persistency criteria.
Comparable degradation rates are expected for biodegradation in surface water, sediment and soil.
An OECD 309 on the relevant constituent of the registered UVCB substance is avaialble. Half lifes of the parent could not be determined due to an insufficient measurement of the mass balance.
Metabolite Identification and Transformation Pathway
Metabolites could be detected in the samples of the test group FT H and FS. A literature review indicated that diphenylamine can be degraded by microorganisms under formation of Aniline and Catechol (1,2-Dihydroxybenzene) [Shin and Spain 2009, Papadopoulou et al. 2018]. This information was adapted to this test item and 4-tert-Butylaniline (CAS-No. 769-92-6) and 4-tertButylcatechol (CAS-No. 98-29-3) were hypothesized as possible metabolites according to Figure 5. These metabolites were also postulated by the software CATALOGIC 301C (v.11.15, LMC Oasis). Samples from the extracts of the storage vessels for the water phase of the groups FTH and FS were selected for the metabolite analysis.
4-tert-Butylaniline could be detected as metabolite in the storage vessel extract of the water samples from day 59. This is in accordance with the radiometric analysis which showed an increase in % of M2 between day 49 and day 59.
Metabolites:
3 metabolites have been detected:
Metabolite 1: 4-tert-Butylaniline (CAS-No. 769-92-6); confirmed by analysis
Metabolite 2: 4-tertButylcatechol (CAS-No. 98-29-3) ; suggested metabolite which was finally not confirmed by analysis
Metabolite 3: metabolite, which could not be characterized
impurity Diphenylamine:
An available REACH dossier indictes that Diphenylamine(CAS: 122-39-4) is inherently degradable not fulfilling specific criteria.
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