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Environmental fate & pathways

Hydrolysis

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Description of key information

Hydrolytically unstable with the half-life time of < 10 minutes at 25 deg. C at pH 4, 7 and < 5 minutes at pH 9.

Key value for chemical safety assessment

Half-life for hydrolysis:
10 min
at the temperature of:
25 °C

Additional information

Study was performed by using OECD 111 in accordance with GLP. However, as the substance is hydrolytically unstable it was not possible to perform the test as outlined in the guidelines. In order to obtain as much information on hydrolysis as possible, an alternative test was designed. The hydrolytic stability was tested in buffered aqueous solutions at pH 4.0, 7.0, and 9.0 at 25°C for 40 minutes. The progress of the hydrolysis was followed by monitoring the main degradation product; 2-ethylhexanol. Additionally, the formation of a white precipitation was observed during the hydrolysis study. This is due to the formation of the insoluble titanium oxides.

No other degradation products than 2 -ethylhexanol and titanium oxide were identified. According to Tier 3 approach, the response of the hydrolysis product 2-ethylhexanol was > 99% (area). In the chromatograms, small additional peaks were observed. Retention times in test at pH 4 and pH 7 were 3.14 minutes and 10.11 minutes. Retention times in test at pH 9 were 3.16 minutes and 10.21 minutes. All ≤ 1% at the specific mass fragments monitored. The additional peaks might derive from impurities in the test substance and/or hydrolysis products. To achieve sufficient sensitivity for the analysis of the identified hydrolysis product, selected ion monitoring was used as detection method. Therefore it was not possible to obtain accurate information on the mass fraction of the unknown peaks or to record their entire mass spectrum, and hence it was not possible to identify these additional peaks.

The results of this study are considered reliable to be used for C&L purposes to conclude this substance to be hydrolytically unstable releasing only 2 -ethylhexanol and hydrated titanium dioxide when in contact with water. Based on the results this substance can be considered as rapidly degradable.