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Physical & Chemical properties

Water solubility

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Description of key information

Slightly soluble.
pH of saturated solution: 7

Key value for chemical safety assessment

Water solubility:
13.4 mg/L
at the temperature of:
20 °C

Additional information

Two fully reliable, GLP, studies are available:

- The Firmenich 2009f study was conducted according to the standard flask method. The 24h sample was considered not to have reached equilibrium, therefore the mean of 48 and 72h results was retained. Minor weakness (incomplete method validation, excess test item) were not considered to affect significantly the validity. However, due to the low value obtained, 1.93 mg/L, it was decided to re-run a new study, with a modified slow-stirring protocol, considered more suitable for low soluble liquid substances.

- In the Noack 2015 study, the mixture was slowly agitated and equilibrated for 72 +24h before sampling, the analytical method was fully validated, and the plateau concentration was determined as 13.4 mg/L.

No pH-dependency (no ionisable function) and no surface-active potential are anticipated, that could explain the difference and its direction, nor the test conditions as described in the report.

However, in the second study, the typical chromatogram of the test solution shows a secondary, unidentified, peak, that leads to suspected degradation. According to the sponsor, no hydrolysis is anticipated. Photolysis can't be proven, as in the slow-stir study, the vessels were protected from light, but this was not specified in the first study report, and the information are not sufficient to confirm the degradation hypothesis. Moreover it should be considered that the chemical structure contains a conjugated system.

Therefore the higher result is retained as key value, as considered to reflect better the solubility of the parent compound.