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Hydrolysis

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Reference
Endpoint:
hydrolysis
Type of information:
experimental study
Adequacy of study:
key study
Study period:
October 2016
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
Study conducted according to OECD Guideline 111 without deviation, not under GLP and with certificate of analysis included.
Reason / purpose:
reference to other study
Qualifier:
according to
Guideline:
OECD Guideline 111 (Hydrolysis as a Function of pH)
Version / remarks:
only 1st trial was conducted.
Deviations:
no
Remarks:
Only 1st trial was conducted.
GLP compliance:
no
Remarks:
This study is a preliminary study, this the reason why it was not conducted according to GLP.
Specific details on test material used for the study:
Colour: Colourless to very pale yellow liquid
Purity: 94.8%
Test substance storage: Refrigeration (+2°C to +8°C) under nitrogen. Keep away from light and humidity
Date of manufacture: 18 September 2015
Expiry date: 17 September 2017
Physico-chemical Properties:
Specific Gravity: 0.916 at 20°C
Vapour Pressure: 0.0424 Pa (25 °C)
Solubility in water: 25.83 mg.L-1 (Slow-stirring method)
log Kow: 4.4 at 35°C (HPLC Method)
Radiolabelling:
no
Analytical monitoring:
yes
Details on sampling:
A stock test item solution was prepared at 1.05 g/L in acetonitrile by adding 10.5 mg of the test item in 10mL of acetonitrile. The solution is then shake. For each pH condition, solutions at 10.5mg/L of test item were prepared by mixing 1 mL of the stock solution with 100 mL buffer solutions, and the solutions obtained were divided in 10 replicates of 10 mL by filling the flasks totally. Each replicate is shake again.
Buffers:
pH=4: CH3COOH at 8.49x10-3 mol.L-1 and CH3COONa,3H2O at 1.51x10-3 mol.L-1. 102 mg of CH3COOH were weighed into a 200mL graduated flask containing 150 mL of ultrapure water. 41 mg of CH3COONa,3H2O were added to the solution and the total volume was adjusted to 200 mL with water. This buffered solution was prepared on 20/10/2016.

pH=7: NaH2PO4,H2O at 4.23x10-3 mol.L-1 and Na2HPO4,7H2O at 5.77x10-3 mol.L-1. 116.8 mg of NaH2PO4,H2O were weighed into a 200 mL graduated flask containing 150 mL of ultrapure water. 309.4 mg of Na2HPO4,7H2O were added to the solution and the total volume was adjusted to 200 mL with water. This buffered solution was prepared on 20/10/2016.

pH=9: Na2B4O7,10H2O at 9.99x10-3 mol.L-1. 762.6 mg of Na2B4O7,10H2O were weighed into a 200 mL graduated flask containing 180 mL of ultrapure water. pH was adjusted to 9 with HCl 0.1M and the total volume was completed to 200 mL with water. This buffered solution was prepared on 20/10/2016.
Dissolved oxygen was removed from these solutions by bubbling nitrogen for 5 minutes. These buffer solutions were also sterilised by a 0.2 µm filtration prior to their use.
Duration:
5 d
Temp.:
50 °C
Number of replicates:
Two replicates per pH condition were analysed at each sampling date (15 min, 1 day, 4 days, 5 days)
Positive controls:
no
Negative controls:
yes
Remarks:
The sampling corresponding to incubation times of 15 min at day 0 is considered as a control solution that underwent a very short incubation at 50°C
Preliminary study:
Two replicates per pH condition were analysed at each sampling date (15 min, 1 day, 4 days, 5 days). The sampling corresponding to incubation times of 15 min is considered as a control solution that underwent a very short incubation at 50°C.
All the analyses were carried out on replicates that were not previously opened since their preparation. The replicates were discarded after analysis.
The samples were let to equilibrate to room temperature a few minutes before sampling and analysis.
A dilution by a factor of 20 in a water/acetonitrile mixture (50/50, V/V) was carried out prior to the analysis (50 µL sample + 950 µL water/acetonitrile mixture).
Final pH of the test solutions was controlled at the end of the study.
Transformation products:
not measured
Remarks:
Only the first trial of OECD 111 study was conducted and no transformation product was checked.
Key result
Remarks on result:
hydrolytically stable based on preliminary test
Remarks:
The substance is hydrolytically stable based on a preliminary test, therefore no further study was performed.
Other kinetic parameters:
Hydrolysis half-life at 25°C is higher than one year.

The following tables present the measured concentrations (in mg/L) for each pH condition and for each sampling time:

Condition

pH=4

Incubation time

15 min

1 day

4 days

5 days

replicate 1

10.36

9.88

9.40

9.23

replicate 2

10.72

10.13

9.26

9.25

Mean

10.54

10.01

9.33

9.24

Condition

pH=7

Incubation time

15 min

1 day

4 days

5 days

replicate 1

10.72

10.20

10.38

10.16

replicate 2

10.75

10.23

10.23

9.89

Mean

10.73

10.21

10.31

10.03

Condition

pH=9

Incubation time

15 min

1 day

4 days

5 days

replicate 1

10.20

10.23

10.31

10.25

replicate 2

10.33

10.28

10.16

10.27

Mean

10.26

10.26

10.24

10.26

At the end of the experiment, the pH of each buffer solution was 4.38, 7.24 and 8.91 (it was measured in replicate 2 for each pH condition, as results were identical between the two replicates).

Validity criteria fulfilled:
yes
Conclusions:
For each pH condition, the total test item loss was calculated by subtracting the mean concentration between the to replicates obtained after 15 minutes of incubation by the mean concentration between the two replicates obtained on the day 5. The relative losses observed after 5 days of incubation in the dark and at 50°C in solutions buffered at pH 4, pH 7 and pH 9 were:
- 12% loss at pH 4
- 7% loss at pH 7
- no loss at pH 9
Therefore, test item 2-ETHYL-4-(2,2,3-TRIMETHYL-3-CYCLOPENTEN-1-YL)-(2E)-BUTEN-1-OL is stable to hydrolysis (hydrolysis half-life is higher than one year at 25°C) and no additional testing is required.
Executive summary:

A study was performed in accordance with OECD Guidline for Testing of Chemicals No. 111, "Hydrolysis as a function of pH"

to determine the stability to hydrolysis of test item 2-ETHYL-4-(2,2,3-TRIMETHYL-3-CYCLOPENTEN-1-YL)-(2E)-BUTEN-1-OL.

In the preliminary study, two replicates per pH condition were analysed at each sampling date (15 min, 1 day, 4 days, 5 days). The sampling corresponding to incubation times of 15 min at day 0 is considered as a control solution that underwent a very short incubation at 50°C.

The relative losses observed after 5 days of incubation in the dark and at 50°C in solutions buffered at pH 4, pH 7 and pH 9 were:

-  12% loss at pH 4,

-  7% loss at pH 7,

-  no loss at pH 9.

Therefore, test item 2-ETHYL-4-(2,2,3-TRIMETHYL-3-CYCLOPENTEN-1-YL)-(2E)-BUTEN-1-OL is stable to hydrolysis (hydrolysis half-life is higher than one year at 25°C) and no additional testing is required.

Description of key information

Test item 2-ETHYL-4-(2,2,3-TRIMETHYL-3-CYCLOPENTEN-1-YL)-(2E)-BUTEN-1-OL is stable to hydrolysis (hydrolysis half-life is higher than one year at 25°C) and no additional testing is required.

Key value for chemical safety assessment

Half-life for hydrolysis:
1 yr
at the temperature of:
25 °C

Additional information

The stability to hydrolysis of the test item was determined in a study performed in accordance with OECD Guidline for Testing of Chemicals No. 111 (first trial only).