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Two key studies evaluating the hydrolysis of Trigonox 101 are available. The first study was the preliminary study and the second study was the definitive study.

In the preliminary study (Vos, 2010), two sets of results are available (Dupont and AkzoNobel) but were included in the same report. The tests were both performed under GLP and following OECD guideline 111, and in both case significant decomposition of Trigonox 101 occurred within 24 hours at pH4, 7 and 9. As the possible hydrolysis product TBA (tertiary-butyl alcohol) could not be detected no confirmation of the increase of this product in 24 hours could be given. Unfortunately, only the screening studies performed at 50°C have been conducted, however, as the results are consistent the test substance is expected to decompose rapidly in aqueous samples but the hydrolysis route is not yet known. These results can be considered as hydrolysis of the test substance. The half-life can be tenetaively determined as between 4 and 13 hours at 50°C and extrapolated to 44.1 -143 hours at all three pHs at 20°C using the Arrhenius equation.

In the definitive study (Habeck, 2011), performed under GLP and following OECD Guideline 111 and EU Method C.7, the results showed a half-life time comprised between 3.8 and 4.4 hours for all pHs (4, 7 and 9) at 20°C.

To consider the worst case, a half-life for hydrolysis of 4.4 hours at 20°C is used as key value for chemical safety assessment.