Reaction mass of 2,6-bis(1-phenylethyl)phenol and 2,4,6-tris(1-phenylethyl)phenol

Hydrolysis

Description of key information

DSP: considered hydrotically stable under the test conditions.

Additional information

No study are available on the reaction mass of 2,4,6 -tris(1 -phenylethyl) phenol and Bis(1 -phenylethyl) phenol for this endpoint. However, one reliable study (Lange, 2006) is available for one of its main components (i. e. Distyrenated phenol). Therefore, it has been selected as key study.

In this study, the hydrolysis potential of Distyrenated Phenol was determined following the GLP and the OECD guideline 111 (2004) with the following deviations:

- buffer solutions at pH levels above and below pH 7 were not tested

- additionally to the buffer solution at pH 7, algal test medium was tested

- the test solutions were saturated with nitrogen and oxygen

- the test was conducted at one temperature.

Moreover , the study was conducted with a test item concentration of 1 mg/L, which is above its concentration of saturation in water. Therefore,

an amount of 10% (v/v) of acetonitrile was added to each sample as co-solvent, to secure the total dissolution of the test item. The study was conducted at a temperature of 20 +/- 0.1°C.

The following four different test conditions were applied:

1) Buffer solution at pH 7 saturated with nitrogen

2) Algal test medium (according to OECD TG 201) saturated with nitrogen

3) Buffer solution at pH 7 saturated with oxygen

4) Algal test medium (according to OECD TG 201) saturated with oxygen

Analyses of the test item were performed via HPLC-DAD on a C18 column in gradient mode using external standard. The peak area of two peaks of the different isomers of the test item were summed for evaluation. Samples were taken and analysed at test start and 6 spaced points over the study duration of 28 days. Control samples were analysed at test start and test end and there was no analytical interference with the test item. Solvent control samples were analysed at test start and test end to confirm the inertness of the co-solvent (acetonitrile) in regard to the test item, no degradation was observed for these samples. For estimation of half-lives and rate constants, a minimum of 5 independent data points (mean values of two replicates, including 0h) have been used.

The test item was found to be minimal to slightly eliminated over the study duration. Half-lives between 95 and 315 days were estimated. The estimated reaction rate constants and half-lives for the test item were calculated despite of a minimal elimination of the test item over the study duration. Therefore the obtained values are highly estimated and should be used with caution. The presence of oxygen has no influence on the degradation behaviour of the test item. No additional peaks were found over the study duration, which indicates that no detectable degradation products were formed. Due to the deviations from the OECD guideline (described above), this study is considered as reliable with restrictions.