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Hydrolysis

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Endpoint:
hydrolysis
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From 2019-05-23 to 2019-07-08
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Reason / purpose for cross-reference:
reference to other study
Qualifier:
according to guideline
Guideline:
OECD Guideline 111 (Hydrolysis as a Function of pH)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Radiolabelling:
no
Analytical monitoring:
yes
Details on sampling:
- Sampling intervals for the parent/transformation products: see in the below table
- Sampling method: not specified
- Sampling methods for the volatile compounds, if any: not specified
- Sampling intervals/times for pH measurements: not specified
- Sampling intervals/times for sterility check: At the end of the experiment samples of the test solutions from each temperature were submitted for sterility confirmation. Samples were investigated by plating experiment on Columbia blood agar plates. The agar plates were incubated at 37 °C, for 24 hours, and at 20 °C for 24 hours, thereafter evaluated. No microbial growth was obtained, the plates remained clear.
- Sample storage conditions before analysis: not specified
- Other observation, if any (e.g.: precipitation, color change etc.): none reported
Buffers:
pH 4.0: 2.0 mL 0.2 M Sodium hydroxide and 250 mL 0.2 M Potassium hydrogen phthalate were diluted to 1000 mL with ultra-pure water Different amounts of the sterile buffer solution were prepared keeping the above ratio using reagent grade chemicals and ultra-pure, sterile water. Nitrogen was bubbled into the water for five minutes before the preparation of the solution in order to exclude oxygen. The pH of the buffer solution was checked with a calibrated pH meter to a precision of 0.001.
Details on test conditions:
TEST SYSTEM
- Type, material and volume of test flasks, other equipment used: 20 mL headspace vials
- Sterilisation method: see below
- Lighting:in the dark
- Measures to exclude oxygen: Nitrogen was bubbled into the water for five minutes before the preparation of the solution in order to exclude oxygen
- Details on test procedure for unstable compounds: not specified
- Details of traps for volatile, if any : not specified
- If no traps were used, is the test system closed/open open
- Is there any indication of the test material adsorbing to the walls of the test apparatus? Not specified

TEST MEDIUM
- Volume used/treatment 20 mL
- Kind and purity of water: ultra-pure water
- Preparation of test medium: About 1 g (or 0.5 g) of the test item was weighed to the nearest 0.1 mg into a volumetric flask and dissolved in the buffer solution to a total volume of 1000 mL (or 500 mL). Test solution was transferred into 20 mL headspace vials under sterile conditions, under a laminar flow hood. The tubes were entirely filled with the solution and then thermostated.
- Renewal of test solution: none
- Identity and concentration of co-solvent: none used

OTHER TEST CONDITIONS
- Adjustment of pH: not specified
- Dissolved oxygen: not specified
Duration:
190 h
pH:
4
Temp.:
20 °C
Initial conc. measured:
942 mg/L
Duration:
53 h
pH:
4
Temp.:
30 °C
Initial conc. measured:
1 057 mg/L
Duration:
17 h
pH:
4
Temp.:
40 °C
Initial conc. measured:
1 002 mg/L
Positive controls:
no
Negative controls:
no
Transformation products:
not measured
Key result
pH:
4
Temp.:
20 °C
Hydrolysis rate constant:
0.008 h-1
DT50:
82 h
Type:
(pseudo-)first order (= half-life)
Remarks on result:
other: Observed
Key result
pH:
4
Temp.:
30 °C
Hydrolysis rate constant:
0.039 h-1
DT50:
18 h
Type:
(pseudo-)first order (= half-life)
Key result
pH:
4
Temp.:
40 °C
Hydrolysis rate constant:
0.114 h-1
DT50:
6.1 h
Type:
(pseudo-)first order (= half-life)
Key result
pH:
4
Temp.:
20 °C
Hydrolysis rate constant:
0.009 h-1
DT50:
77 h
Type:
(pseudo-)first order (= half-life)
Remarks on result:
other: Calculated
Details on results:
TEST CONDITIONS
- pH, sterility, temperature, and other experimental conditions maintained throughout the study: Yes
- Anomalies or problems encountered (if yes): none specified

TRANSFORMATION PRODUCTS not determined

MINERALISATION (distinguish between dark and irradiated samples) NA

INDICATION OF UNSTABLE TRANSFORMATION PRODUCTS: NA

VOLATILIZATION (at end of study) not specified

UNIDENTIFIED RADIOACTIVITY (at end of study) NA

PATHWAYS OF HYDROLYSIS
- Description of pathwayS: not specified
- Figures of chemical structures attached: No

SUPPLEMENTARY EXPERIMENT (if any): RESULTS: NA
Validity criteria fulfilled:
not specified
Conclusions:
The following results were obtained:
pH 4: 20 °C: half life: 82 h
30 °C: half life: 18 h
40 °C: half life: 6.1 h
20 °C: half life: 77 h (calculated)
Executive summary:

In the course of the preliminary test 2,5-Dimethoxytetrahydrofuran was found to be unstable at pH 4 at 50±0.5 °C. The purpose of this study was to perform the hydrolysis main test (Tier 2) and evaluate the abiotic degradation of 2,5-Dimethoxytetrahydrofuran at pH 4 applying three different temperatures (20, 30 and 40 ± 0.5 °C in the dark), according to OECD 111 guideline and C7 EU method, and following GLP.

The following results were obtained:

pH 4: 20 °C: half life: 82 h

30 °C: half life: 18 h

40 °C: half life: 6.1 h

20 °C: half life: 77 h (calculated)

Endpoint:
hydrolysis
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From 2019-05-06 to 2019-06-17
Reliability:
1 (reliable without restriction)
Qualifier:
according to guideline
Guideline:
OECD Guideline 111 (Hydrolysis as a Function of pH)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Radiolabelling:
no
Analytical monitoring:
yes
Details on sampling:
- Sampling intervals for the parent/transformation products: The reaction solutions were analysed at the start of the test and after five days with three replicate samples.
- Sampling method: not indicated
- Sampling intervals/times for pH measurements: at the beginning
- Sampling intervals/times for sterility check: not performed
- Sample storage conditions before analysis: Samples were diluted with acetonitrile and analysed by the previously validated GC-MS method.
- Other observation, if any (e.g.: precipitation, color change etc.): none reported
Buffers:
pH 4.0: 1.0 mL 0.2 M Sodium hydroxide and 125 mL 0.2 M Potassium hydrogen phthalate were diluted to 500 mL with ultra-pure water
pH 7.0: 74 mL 0.2 M Sodium hydroxide and 125 mL 0.2 M Potassium dihydrogen phosphate were diluted to 500 mL with ultra-pure water
pH 9.0: 53.5 mL 0.2 M Sodium hydroxide and 125 mL 0.2 M Boric acid and Potassium chloride were diluted to 500 mL with ultra-pure water
These sterile buffer solutions were prepared using reagent grade chemicals and ultra-pure, sterile water. Nitrogen was bubbled into the water for five minutes before the preparation of the solutions in order to exclude oxygen. The pH of each buffer solution was checked with a calibrated pH meter to a precision of 0.001.
Details on test conditions:
TEST SYSTEM
- Type, material and volume of test flasks, other equipment used:
- Sterilisation method:
- Lighting/Measures taken to avoid photolytic effects: dark thermostat to avoid photolytic effects
- Measures to exclude oxygen: Nitrogen was bubbled into the water for five minutes before the preparation of the solutions in order to exclude oxygen
- Details on test procedure for unstable compounds: not indicated
- Details of traps for volatile, if any : not indicated
- If no traps were used, is the test system closed/open : open
- Is there any indication of the test material adsorbing to the walls of the test apparatus? Not indicated

TEST MEDIUM
- Volume used/treatment : 20 mL
- Kind and purity of water: ultra-pure water
- Preparation of test medium: About 250 mg of test item was weighed to the nearest 0.1 mg into a volumetric flask and dissolved in the buffer solutions to a total volume of 250 mL. Test solution was transferred into 20 mL headspace vials under sterile conditions, under a laminar flow hood. The tubes were entirely filled with the solution.
- Renewal of test solution: none
- Identity and concentration of co-solvent: none used

OTHER TEST CONDITIONS
- Adjustment of pH: none
- Dissolved oxygen: not indicated
Duration:
120 h
Number of replicates:
3
Positive controls:
no
Negative controls:
no
Transformation products:
not measured
% Recovery:
0
pH:
4
Temp.:
50 °C
Duration:
120 h
% Recovery:
97
pH:
7
Temp.:
50 °C
Duration:
120 h
% Recovery:
> 100
pH:
9
Temp.:
50 °C
Duration:
120 h
Remarks on result:
other: See record of the main study
Validity criteria fulfilled:
not specified
Conclusions:
pH 4: 100 % hydrolysis
pH 7: 2 % hydrolysis
pH 9: 0 % hydrolysis
Based on the results obtained, 2,5-Dimethoxytetrahydrofuran can be considered as hydrolytically stable at pH 7 and pH 9, and hydrolytically unstable at pH 4 under the conditions investigated.
Executive summary:

The purpose of this study was to evaluate the hydrolysis of 2,5-Dimethoxytetrahydrofuran in solutions of three different pH values, according to OECD 111 guideline and C7 EU method and following GLP. In the course of this study the preliminary test was carried out.

The preliminary test was performed at 50 ± 0.5 °C in pH 4, 7 and 9 solutions. More than 10 per cent of hydrolysis was observed after five days at pH 4. The following results were obtained:

pH 4: 100 % hydrolysis

pH 7: 2 % hydrolysis

pH 9: 0 % hydrolysis

Based on the results obtained, 2,5-Dimethoxytetrahydrofuran can be considered as hydrolytically stable at pH 7 and pH 9, and hydrolytically unstable at pH 4 under the conditions investigated.

Description of key information

In the course of the preliminary test 2,5-Dimethoxytetrahydrofuran proved to be hydrolytically stable at pH 7 and pH 9. Therefore hydrolysis main test was performed in pH 4 solution.

The following results were obtained:

pH 4: 20 °C: half life: 82 h

30 °C: half life: 18 h

40 °C: half life: 6.1 h

20 °C: half life: 77 h (calculated)

Key value for chemical safety assessment

Additional information