Registration Dossier

Environmental fate & pathways

Hydrolysis

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Description of key information

OS3600 is considered hydrolytically unstable based on the read-across approach from the analogues OS1600 and OS2600 (half-life times at room temperature were < 4 minutes at pH 4, 7 and 9). A hydrolysis test was also performed on MPKO, the hydrolytic product of OS3600. MPKO was considered to be hydrolytically stable (i.e. half-life time of > 1 year at 25°C) at pH 4, pH 7 and pH 9.

Key value for chemical safety assessment

Half-life for hydrolysis:
4 min
at the temperature of:
20 °C

Additional information

Data waiving: The substance OS3600 is considered to be hydrolytically unstable in water with extremely short life-time (half-life times < 4 minutes at room temperature and pH 4, 7 and 9 were measured in analogues OS1600 and OS2600). In accordance with REACH Annex XI, hydrolysis testing may be omitted if it is technically not possible to conduct the study.

Supporting study: Read-across approach from experimental data on the analogue substance OS1600:

A hydrolysis test was performed on the analogue OS1600 in accordance with the OECD Guideline 111 (GLP study).When using 25 ml buffer solution pH4, pH 7, pH 9 a > 50% decrease concentration was observed after 4 minutes which demonstrates that the half-life time of the test substance is < 4 minutes at room temperature. Based on these results, OS3600 was determined to be hydrolytically unstalbe at pH 4, 7 and 9.

Supporting study: Read-across approach from experimental data on the analogue substance OS2600:

A screening test based on OECD Guideline 111 and EU Method C.7 (GLP study) on the analogue OS2600, showed that the substance hydrolyses very fast at room temperature and pH 4, 7 and 9 (half-life time < 4 minutes). Based on these results, the substance OS3600 was determined to be hydrolytically unstable with short half-lifes too.

Supporting study: A hydrolysis test was also performed on MPKO, the hydrolytic product of OS3600 in accordance with OECD Guideline 111 and EU Method C.7 (GLP study). In all tests performed, a decrease in concentration was observed. At the end of the main tests, concentrations became stable at 50 -60% of the initial concentration. This indicates that equilibrium is formed and that this is not hydrolysis. MPKO is therefore considered hydrolytically stable (i.e. half-life time of > 1 year at 25°C) at pH 4, pH 7 and pH 9.