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Environmental fate & pathways

Hydrolysis

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Description of key information

According to the OECD 111 guideline, the half-life for n-butyl-4,4-bis(tert-butylperoxy)valerate at 25°C has been determined to be 1.7 days at pH 4, 11.3 days at pH 7 and 4.1 days at pH 9. At pH 1.2 and 37°C, the half-life is < 30 min.

Key value for chemical safety assessment

Half-life for hydrolysis:
11.3 d
at the temperature of:
25 °C

Additional information

The rate of hydrolysis of n-butyl-4,4-bis(tert-butylperoxy)valerate as a function of pH was studied according to the OECD 111 Guideline and GLP requirements (Chastenet, 2017). The hydrolysis of the test item was assessed in aqueous buffers at pH 1.2, 4, 7 and 9 at 50 ± 0.5°C. The mean loss of test item, compared to T0, was determined to have changed by more than 10% after 5 days for all tested pH. This indicated that the test item was clearly hydrolytically unstable at all these pH and that significant hydrolysis had occurred.

Therefore, the definitive test was conducted at pH 1.2, 4, 7 and 9. Here are the results of half-life for each pH:

- the half life of the test item at pH 1.2 and 37°C was determined to be < 30 min;

- the half life of the test item at pH 4.0 and 25°C was determined to be 1.7 days (i.e. 41.56 hours);

- the half life of the test item at pH 7.0 and 25°C was determined to be 11.3 days (i.e. 271.32 hours);

- The half life of the test item at pH 9.0 and 25°C was determined to be 4.1 days (i.e. 99.23 hours).

For the characterisation of the hydrolysis product, the concentration of hypothetical hydrolysis products was too low to allow their detection. As a consequence, the organic chemical balance cannot be determined.