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Environmental fate & pathways

Hydrolysis

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Reference
Endpoint:
hydrolysis
Type of information:
experimental study
Adequacy of study:
key study
Study period:
from 21st November 2012 to 14th march 2013
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
GLP study in compliance with international guidelines
Qualifier:
according to guideline
Guideline:
OECD Guideline 111 (Hydrolysis as a Function of pH)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
not applicable
Radiolabelling:
no
Analytical monitoring:
yes
Details on sampling:
Tier 1:
Samples for the GC/FID analysis were taken ate the beginning and after five days.
Tier 2:
Sampling was performed in a suitable time intervals in order to monitor the hydrolysis behaviour of the test item at the different temperatures and pHs.
Tier 3:
Sampling was performed after 42.5 hours and the extract was measured via GC-MS.
Buffers:
Buffer solution, pH 4:
Ch3COOH, 2M
CH3COOHNa, 1M
water

Buffer solution, pH 7
KH2PO4
water
NaOH, 2M
water

Buffer solution, pH9
H3BO3
KCl
water
NaOH, 2M
water
Estimation method (if used):
not applicable
Details on test conditions:
Tier 1:
A solution of the test item in sterilised water was mixed with sterilised buffer solutions (pH values 4,7 and 9). The resulting solutions were stored at 50°C for a period of five days.
Tier 2:
A solution of the test item in sterilised water was mixed with sterilised buffer solutions (pH values 4,7 and 9). The resulting solutions were stored at 10, 25 and 50°C.
Tier 3:
A solution of the test item in sterilised water was mixed with sterilised buffer solutions (pH 9). The resulting solutions were stored at 50°C.
Duration:
5 d
Initial conc. measured:
10 mg/L
Duration:
4 d
Initial conc. measured:
>= 10 - <= 12 mg/L
Duration:
3
pH:
9
Temp.:
50 °C
Initial conc. measured:
10 mg/L
Number of replicates:
Tier 1:
3 per pH
Tier 2:
16 per pH
Tier 3:
2
Positive controls:
no
Negative controls:
no
Statistical methods:
not applicable
Preliminary study:
After five days (120h), the areas of the test item were lower than 17% of the start area at all three pH values: 4, 7 and 9. The test item can be considered as hydrolytically instable at all three pH values. Following the guidelines, tier 2 has to be conducted.
Test performance:
For tier 1, a solution of the test item was prepared by spiking of 400 mL autoclaved demineralised water with 4 mL of test item solution in methanol (1000 mg/L), resulting in a nominal concentration of the test item in water of 10 mg/L. All flasks were stored at 50 °C in an incubation chamber. The residuals of the test solutions were extracted immediately, giving the initial values.For tier 2 (10 °C and 25 °C, all pH values), a solution of the test item was prepared by spiking of 1000 mL demineralised water with 6 mL of test item solution in methanol (2000 mg/L), resulting in a nominal concentration of the test item in water 12 mg/L. All flasks were stored at the test temperature in an incubation chamber. The residual of the test solution were extracted immediately, giving an initial value. For tier 2 (pH 4 at 50 °C), a solution of the test item was prepared by spiking of 1493 g demineralised water with 7.5 mL of test item solution in methanol (2000 mg/L), resulting in a nominal concentration of the test item in water approx. 10 mg/L. For tier 2 (pHs 7 and 9 at 50 °C), a solution of the test item was prepared by spiking of 1300 g demineralised water with 6.5 mL of test item solution in methanol (2000 mg/L), re-sulting in a nominal concentration of the test item in water approx. 10 mg/L. For each sampling time, two fresh flasks were used to avoid microbial contamination and contact with oxygen.
For tier 3 (pH 9), a solution of the test item was prepared by spiking of 199 g demineral-ised water with 1 mL of test item solution in methanol (2000 mg/L), resulting in a nominal concentration of the test item in water approx. 10 mg/L. Two test flasks (100 mL) were filled with the test solution leaving no headspace and stored at 50 °C for approximately 42.5 hours in order to obtain nearly complete hydrolysis of the test item.
Transformation products:
yes
No.:
#1
% Recovery:
>= 22.8 - <= 91.9
pH:
4
Temp.:
10 °C
Duration:
7 d
% Recovery:
>= 25.9 - <= 91.9
pH:
7
Temp.:
10 °C
Duration:
7 d
% Recovery:
>= 19.5 - <= 91.6
pH:
9
Temp.:
10 °C
Duration:
7 d
% Recovery:
>= 25.5 - <= 95.1
pH:
4
Temp.:
25 °C
Duration:
5 d
% Recovery:
>= 13.5 - <= 84.1
pH:
7
Temp.:
25 °C
Duration:
5 d
% Recovery:
>= 20.2 - <= 86.2
pH:
9
Temp.:
25 °C
Duration:
5 d
% Recovery:
>= 32.4 - <= 96.9
pH:
4
Temp.:
50 °C
Duration:
4 d
% Recovery:
>= 23.9 - <= 93.6
pH:
7
Temp.:
50 °C
Duration:
4 d
% Recovery:
>= 1.3 - <= 83.6
pH:
9
Temp.:
50 °C
Duration:
4 d
pH:
4
Temp.:
50 °C
Hydrolysis rate constant:
0.028 h-1
DT50:
25.2 h
Type:
(pseudo-)first order (= half-life)
Remarks on result:
other: R^2=0.9502
pH:
7
Temp.:
50 °C
Hydrolysis rate constant:
0.021 h-1
DT50:
32.9 h
Type:
(pseudo-)first order (= half-life)
Remarks on result:
other: R^2=0.9904
pH:
9
Temp.:
50 °C
Hydrolysis rate constant:
0.068 h-1
DT50:
10.2 h
Type:
(pseudo-)first order (= half-life)
Remarks on result:
other: R^2=0.9901
pH:
4
Temp.:
25 °C
Hydrolysis rate constant:
0.019 h-1
DT50:
37.3 h
Type:
(pseudo-)first order (= half-life)
Remarks on result:
other: R^2=0.9876
pH:
7
Temp.:
25 °C
Hydrolysis rate constant:
0.018 h-1
DT50:
37.9 h
Type:
(pseudo-)first order (= half-life)
Remarks on result:
other: R^2=0.9985
pH:
9
Temp.:
25 °C
Hydrolysis rate constant:
0.015 h-1
DT50:
44.8 h
Type:
(pseudo-)first order (= half-life)
Remarks on result:
other: R^2=0.9859
pH:
4
Temp.:
10 °C
Hydrolysis rate constant:
0.015 h-1
DT50:
47.2 h
Type:
(pseudo-)first order (= half-life)
Remarks on result:
other: R^=0.9908
pH:
7
Temp.:
10 °C
Hydrolysis rate constant:
0.014 h-1
DT50:
50.7 h
Type:
(pseudo-)first order (= half-life)
Remarks on result:
other: R^2=0.9927
pH:
9
Temp.:
10 °C
Hydrolysis rate constant:
0.014 h-1
DT50:
50.7 h
Type:
(pseudo-)first order (= half-life)
Remarks on result:
other: R^2=0.9927
Key result
Temp.:
50 °C
Hydrolysis rate constant:
0.116 h-1
DT50:
5.96 h
Type:
(pseudo-)first order (= half-life)
Key result
Temp.:
25 °C
Hydrolysis rate constant:
0.052 h-1
DT50:
13.25 h
Type:
(pseudo-)first order (= half-life)
Key result
Temp.:
10 °C
Hydrolysis rate constant:
0.039 h-1
DT50:
17.59 h
Type:
(pseudo-)first order (= half-life)
Other kinetic parameters:
not applicable
Details on results:
One additional signal at 2.6 minutes was observed after the hydrolysis of the test item at pH 9. The peak was identified via GC/MS analysis under non-GLP conditions as the expected product of alkaline hydrolysis 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluooctyl alcohol.
Validity criteria fulfilled:
yes
Conclusions:
Using the Arrhenius equation, the following parameters were calculated for hydrolytical behaviour of 3,3,4,4,5,5,6,6,7,7,8,8,8-Tridecafluorooctyl acrylate at 20 °C:
Kobs = 0.04917
t1/2 = 14.1 h
As hydrolysis product 3,3,4,4,5,5,6,6,7,7,8,8,8-Tridecafluorooctyl alcohol was identified.
Executive summary:

Hydrolysis behaviour of the test item 3,3,4,4,5,5,6,6,7,7,8,8,8-Tridecafluorooctyl acrylate was examined at three different pH values and three different temperatures. At 10 °C, 25 °C and 50 °C, hydrolysis was completed within 1 – 5 days. Therefore, the test item can be considered as hydrolytically unstable at all pH values 4, 7 and 9.

Half-life determined in the study were 5.96 hours at 50 °C, 13.25 hours at 25 °C and 17.59 Hours at 10 °C, indicative of hydrolysis over a pH range of 4 - 9, and by calculation a half-life of 14.1 hours at 20 °C is derived.

Ester decomposition is usually catalysed both by acids and bases. The test item 3,3,4,4,5,5,6,6,7,7,8,8,8-Tridecafluorooctyl acrylate seems to be affected much more quickly by acids at 10 °C and 25 °C, but at 50 °C the hydrolysis was quicker at pH 9. An additional signal was observed in the GC-chromatogram (at approx. 2.6 min.) at pH 9 only and was identified via GC/MS analysis in the under non-GLP conditions as 3,3,4,4,5,5,6,6,7,7,8,8,8-Tridecafluorooctyl alcohol.

Hydrolysis rates are higher with increasing temperature.

All validity criteria for analytical method and determination of hydrolysis were met; repeatability of the values was very good, and coefficients of determination all lay above 0.95.

Temperature dependencies of the hydrolysis constants fit very well the Arrhenius equation indicating that the reaction is pseudo-first order indeed.

Description of key information

According to OECD 111 the test item was determined to be hydrolytically unstable at pH 4, 7 and 9 (t½ = 17.59 hours at 10 °C, t½ = 13.25 hours at 25 °C; t½ = 5.96 hours at 50 °C).

Using the Arrhenius equation, the following parameters were calculated for hydrolytical behaviour of 3,3,4,4,5,5,6,6,7,7,8,8,8-Tridecafluorooctyl acrylate at 20 °C:

Kobs = 0.04917

t1/2 = 14.1 h

As hydrolysis product 3,3,4,4,5,5,6,6,7,7,8,8,8-Tridecafluorooctyl alcohol was identified.

Key value for chemical safety assessment

Half-life for hydrolysis:
13.25 h
at the temperature of:
25 °C

Additional information

A GLP study conducted according to OECD guidelines 111 is available.

The hydrolysis behaviour of the test item 3,3,4,4,5,5,6,6,7,7,8,8,8 -tridecafluorooctyl acrylate was examined at three different pH values and three different temperatures. At 10 °C, 25 °C and 50 °C, hydrolysis was completed within 1 – 5 days. Therefore, the test item can be considered as hydrolytically unstable at all pH values 4, 7 and 9.

Ester decomposition is usually catalysed both by acids and bases. The test item 3,3,4,4,5,5,6,6,7,7,8,8,8-Tridecafluorooctyl acrylate seems to be affected much more quickly by acids at 10 °C and 25 °C, but at 50 °C the hydrolysis was quicker at pH 9. An additional signal was observed in the GC-chromatogram (at approx. 2.6 min.) at pH 9 only and was identified via GC/MS analysis in the laboratory Dr. Appelt in Mannheim under non-GLP conditions as 3,3,4,4,5,5,6,6,7,7,8,8,8 -tridecafluorooctyl alcohol.

Hydrolysis rates are higher with increasing temperature.

All validity criteria for analytical method and determination of hydrolysis were met; repeatability of the values was very good, and coefficients of determination all lay above 0.95.

Temperature dependencies of the hydrolysis constants fit very well the Arrhenius equation indicating that the reaction is pseudo-first order indeed.