2,3-dihydro-2,2,6-trimethylbenzaldehyde

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From October 26, 2020 to November 18, 2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

The water solubility of Safranal at 20°C is 514.9 mg/I. According to the guidelines, the initial concentration to be used for the hydrolysis reaction should not exceed the half of the saturation concentration, or a concentration of 0.01 mol/1.
A nominal concentration of 200 mg/I was used in the preliminary test. Therefore, 200 mg of test substance were added in a 1000 ml volumetric flask and completed with buffer solution. The HPLC method is capable of quantifying concentrations of this magnitude.
Preliminary test at 50°C (Tier 1) : Solutions of Safranal P in the different buffer solutions were prepared as described above. For each pH, a minimum of 24 amber glass crimp cap vials (20 ml) were filled with 20 ml of the respective solution, sealed with Teflon coated rubber septa crimp cap, and placed in the water bath at 50°C. After temperature equilibration, a first pair of vials was extracted for each pH. This is time zero of the experiment. At given times, namely after 120 h, other two vials per buffer solution were sacrificed for analysis.

Buffers:

pH 4: Ready-made concentrate (Titrisol®, MERCK, Darmstadt, Germany, art. No. 9884, citrate I hydrochloric acid buffer) pH 4.00 ± 0.02 at 20°C
pH 7: Ready-made concentrate (Titrisol®, MERCK, Darmstadt, Germany, art. No. 9887, phosphate buffer) pH 7.00 ± 0.02 at 20°C
pH 9: Ready-made concentrate (Titrisol®, MERCK, Darmstadt, Germany, art. No. 9889, boric acid / potassium chloride / sodium hydroxide buffer) pH 9.00 ± 0.02 at 20°C
In order to avoid any unnecessary excess of inorganic salts that could reduce the solubility of the test substance, these buffer solutions were diluted to 10% with ultrapure water before being used as test media.

Duration:

5 d

pH:

4

Temp.:

50 °C

Initial conc. measured:

ca. 165.04 mg/L

Remarks:

Average concentration of 2 measured values

Duration:

5 d

pH:

7

Temp.:

50 °C

Initial conc. measured:

ca. 160.62 mg/L

Remarks:

Average concentration of 2 measured values

Duration:

5 d

pH:

9

Temp.:

50 °C

Initial conc. measured:

ca. 156.39 mg/L

Remarks:

Average concentration of 2 measured values

Number of replicates:

2

Transformation products:

not measured

Key result

pH:

4

Temp.:

25 °C

DT50:

> 1 yr

Key result

pH:

7

Temp.:

25 °C

DT50:

> 1 yr

Key result

pH:

9

Temp.:

25 °C

DT50:

> 1 yr

Details on results:

Only a preliminary test was performed. This is aligned with the criterion given in the guidelines:
If less that 10% degradation after 120hours (equivalent to a half-life time higher that 1 year at 25 degrees Celsius) is observed, no further testing is necessary.
This criterion is fulfilled for pH 4, pH 7 and pH 9. For all three pH <10% degradation was observed at 50 degrees Celsius over a 120 hours period (0h to 120h).
Analytical results are given in Table 1 of the study report.

Validity criteria fulfilled:

yes

Conclusions:

The half-life time of Safranal P at 25°C is higher than one year at pH 4, pH 7 and pH 9.

Executive summary:

An abiotic degradation study (hydrolysis as a function of pH) was carried out with Safranal P according to OECD guideline n° 111.

Only the preliminary test needed to be performed at pH 4, pH 7 and pH 9 since, at 50°C, less than 10% hydrolysis occurred after 120 h.

A hydrolysis of less than 10% after 120 h, or more, at 50°C corresponds to a half-life time of more than one year at 25°C.

Therefore: The half-life time of Safranal P at 25°C is higher than one year at pH 4, pH 7 and pH 9.

Description of key information

An abiotic degradation study (hydrolysis as a function of pH) was carried out with Safranal P according to OECD guideline n° 111.

Only the preliminary test needed to be performed at pH 4, pH 7 and pH 9 since, at 50°C, less than 10% hydrolysis occurred after 120 h.

A hydrolysis of less than 10% after 120 h, or more, at 50°C corresponds to a half-life time of more than one year at 25°C.

Therefore: The half-life time of Safranal P at 25°C is higher than one year at pH 4, pH 7 and pH 9.

Key value for chemical safety assessment

Half-life for hydrolysis:

1 yr

at the temperature of:

25 °C