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Environmental fate & pathways

Hydrolysis

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Description of key information

The testing of Ethyl centralite for hydrolysis is relevant to its persistence. Hydrolysis is one of the most common reactions controlling abiotic degradation and is therefore one of the main degradation paths of substances in the environment. 
The procedure was performed according to Method C.7 – Degradation – Abiotic Degradation: Hydrolysis as a Function of pH, Council regulation (EC) No 440/2008. Published in OJ No L 142/518 May 2008.
The preliminary test is performed at 50 +/- 0.5 °C and pH 4.0, 7.0, and 9.0. The selected tested pH values are normally found in the environment. If less than 10% of hydrolysis is observed after 5 days (t0.525°C > 1 year)*, the test substance is considered hydrolytically stable and, normally, no additional testing is required. If more than 10% of hydrolysis is observed within 5 days the test continues with Tire 2. If the substance is known to be unstable at environmentally relevant temperatures, the preliminary test is not required and the test starts with Tier 2 immediately.
*) 10% hydrolysis of a test substance at 50 °C corresponds to half-life of approx. 30 days that corresponds to a value of approx. 1 year at 25 °C.
Some limited data on hydrolysis were found in literature.

Key value for chemical safety assessment

Half-life for hydrolysis:
1 yr
at the temperature of:
50 °C

Additional information

The preliminary test has shown that the test substance was rather stable at any of given pH of buffered solutions, i.e. 4.0, 7.1, and 9.0, during the whole period of 5 days.

The test substance is considered hydrolytically stable (t0.5, 25°C > 1 year) therefore no additional testing (Tier 2, Tier 3) is required.

The resistance of Ethyl centralite to hydrolysis has been attributed to the bulkiness of the ethyl and phenyl substituents.

Ethyl centralite will hydrolyse to an aniline compound only under heated, acidic (100°C, 60% sulfuric acid conditions (Wentsel, 1979), and is resistant to base hydrolysis (Kitchen, 1978).