(2Z)-2-phenylhex-2-enenitrile

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

18-09-2008 to 23-01-2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study performed under GLP. All relevant validity criteria were met.

Remarks:

GLP; well documented study report following a screening study and method to guideline EU Method C.7 or OECD TG 111 (2004) Tier 1 requirements including the regulatory conclusion that the substance is hydrolytically stable at all relevant pH.

Qualifier:

according to guideline

Guideline:

EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)

Deviations:

no

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Deviations:

no

Principles of method if other than guideline:

The test followed a method in accordance with EU Method C.7 and equivalent or similar to OECD TG 111 (hydrolysis as a function of pH) - as a screening study (tier 1) for the hydrolysis properties of the test item.

GLP compliance:

yes (incl. QA statement)

Remarks:

inspected: February 2000; signature: April 2000

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

- Sampling intervals for the parent/transformation products:
Preliminary test (tier 1): 0 hours, 2.4, 4, 6, 24, 48, 74, 96 and 120 hours (as appropriate depending on results).
In the tier 1 test other time periods may have been measured (recorded in the primary data but not included in the presented results).
- Sampling method: Aliquots of the sample solutions were taken from the flasks at various times and the pH of each solution recorded. The concentrations were determined by Gas Chromatography (GC). 1 mL of each sample was diluted with 2 mL of acetone. 1 μL aliquots of the test solutions at each pH value were analysed by Gas Chromatography (GC) in duplicate.
- Sampling methods for the volatile compounds, if any: Not applicable.
- Sampling intervals/times for pH measurements: Not reported.
- Sampling intervals/times for sterility check: Test solutions were was submitted to a 0.2 μm filtration prior to initation. The buffer solutions were sterilized for 25 minutes in an autoclave prior to first use. Nitrogen was passed through the buffer solutions for 5 minutes except when freshly sterilized.
- Sample storage conditions before analysis: On the autosampler prior to analysis.
- Other observation, if any (e.g.: precipitation, color change etc.): None reported.

Buffers:

- Type and final molarity of buffer:
• pH 4 :
biphthalate
• pH 7:
phosphate (anhydrous)
• pH 9 :
borate

Details on test conditions:

TEST SYSTEM
- Type, material and volume of test flasks, other equipment used: stoppered glass flasks
- Sterilisation method: The test solutions and buffer solutions were filtered through a 0.2 µm membrane filter and subject to degassing. Thereby ensuring sterility of the test system.
- Lighting: Not applicable.
- Measures taken to avoid photolytic effects: All solutions shielded from light.
- Measures to exclude oxygen: Filtration and degassing with nitrogen of buffer solutions.
- Details on test procedure for unstable compounds: Not applicable.
- Details of traps for volatile, if any: Not applicable (closed system)
- If no traps were used, is the test system closed/open: Closed system.
- Is there any indication of the test material adsorbing to the walls of the test apparatus?: Not reported.
TEST MEDIUM
- Volume used/treatment: 46.01 to 57.45 mg of test item were dissolved in 2 mL of acetone with aid of sonication and diluted with buffer solution (pH 4.0, 7.0 or 9.0) to a volume of 100 mL to prepare a stock solution of 460.1 to 574.5 μg/mL (dependent on pH). The solution submitted to a 0.2 μm filtration. To obtain a test solution of not more than half the water solubility, 50 mL the solution were diluted to a volume of 100 mL with the respective buffer. Two aliquots of this test solution of approximately 50 mL each were transferred into 50 mL flasks in duplicate. Nitrogen was passed to degassed the system.
- Kind and purity of water: Deionised water.
- Preparation of test medium: The test solutions and buffer solutions were filtered through a 0.2 µm membrane filter and subject to degassing. Thereby ensuring sterility of the test system. Aliquots of the sample solutions were taken from the flasks at various times and the pH of each solution recorded.
- Renewal of test solution: No.
- Identity and concentration of co-solvent: 2 mL acetone.
OTHER TEST CONDITIONS
- Adjustment of pH: No.
- Dissolved oxygen: Minimised.

Number of replicates:

duplicate

Positive controls:

no

Negative controls:

no

Preliminary study:

In the preliminary test (tier 1) at 50 °C:
pH 4: greater than 50% hydrolysis was observed after 2.4 hours. Which is equivalent to a half-life < 1 day at 25 °C.
pH 7: Half-life of 20.8 hours. The extent of hydrolysis after 24 hours indicated a further test at 40 °C would be required to estimate the rate constant and half life.
pH 9: Half-life of 57.0 hours. The extent of hydrolysis after 92.5 hours indicated a further test at 40 °C would be required to estimate the rate constant and half life.
In the definitive test (tier 2) at 40 °C:
In the preliminary test (tier 1) at 50 °C:
pH 4: Less than 10% hydrolysis was observed after 5 days. Which is equivalent to a half-life > 365 days at 25 °C (OECD TG 111).
pH 7: Less than 10% hydrolysis was observed after 5 days. Which is equivalent to a half-life > 365 days at 25 °C (OECD TG 111).
pH 9: Less than 10% hydrolysis was observed after 5 days. Which is equivalent to a half-life > 365 days at 25 °C (OECD TG 111).

Test performance:

No unusual findings were reported in the study. It was observed that concentration had increased > 100% initial in all test replicates.

Transformation products:

not measured

pH:

4

Temp.:

50 °C

DT50:

> 365 d

Type:

(pseudo-)first order (= half-life)

Remarks on result:

hydrolytically stable based on preliminary test

pH:

7

Temp.:

50 °C

DT50:

> 365 d

Type:

(pseudo-)first order (= half-life)

Remarks on result:

hydrolytically stable based on preliminary test

pH:

9

Temp.:

50 °C

DT50:

> 365 d

Type:

(pseudo-)first order (= half-life)

Remarks on result:

hydrolytically stable based on preliminary test

Details on results:

- pH, sterility, temperature, and other experimental conditions maintained throughout the study: Yes. (No indications in the study of any anomalies). Yes, by use of appropriate buffers however pH was not continuously monitored throughout the study, sterility was not examined.
- Anomalies or problems encountered (if yes): No.

MAJOR TRANSFORMATION PRODUCTS
Not examined.

MINOR TRANSFORMATION PRODUCTS
No examined.

MINERALISATION (distinguish between dark and irradiated samples)
Not examined.

INDICATION OF UNSTABLE TRANSFORMATION PRODUCTS:
Not examined.

VOLATILIZATION (at end of study)
Not examined.

UNIDENTIFIED RADIOACTIVITY (at end of study)
Not examined.

PATHWAYS OF HYDROLYSIS
Not examined.

SUPPLEMENTARY EXPERIMENT (if any): RESULTS:
In the preliminary test (tier 1) at 50 °C:
pH 4: Less than 10% hydrolysis was observed after 5 days. Which is equivalent to a half-life > 365 days at 25 °C (OECD TG 111).
pH 7: Less than 10% hydrolysis was observed after 5 days. Which is equivalent to a half-life > 365 days at 25 °C (OECD TG 111).
pH 9: Less than 10% hydrolysis was observed after 5 days. Which is equivalent to a half-life > 365 days at 25 °C (OECD TG 111).
No further testing was considered required.

Validity criteria fulfilled:

yes

Remarks:

GLP; well documented study report following a screening study and method to guideline EU Method C.7 or OECD TG 111 (2004) Tier 1 requirements including the regulatory conclusion that the substance is hydrolytically stable at all relevant pH.

Conclusions:

The substance was found to be stable at pH 4, 7 and 9: due to < 10% degradation after 5 days at 50°C (t1/2: > 365 days at 25°C)

Executive summary:

The test followed a method in accordance with EU Method C.7 (abiotic degradation: hydrolysis as a function of pH) and OECD TG 111 under GLP serving as both a screening study (tier 1) for the hydrolysis properties of the item. The pH 4, 7 and 9 buffer solutions were sterilized for 25 minutes in an autoclave prior to first use. Nitrogen was passed through the buffer solutions for 5 minutes except when freshly sterilized. The study was conducted with the test vessels protected from light. 46.01 to 57.45 mg of test item were dissolved in 2 mL of acetone with aid of sonication and diluted with buffer solution (pH 4.0, 7.0 or 9.0) to a volume of 100 mL to prepare a stock solution of 460.1 to 574.5 μg/mL (dependent on pH). The solution submitted to a 0.2 μm filtration. To obtain a test solution of not more than half the water solubility, 50 mL the solution were diluted to a volume of 100 mL with the respective buffer. Two aliquots of this test solution of approximately 50 mL each were transferred into 50 mL flasks in duplicate. Nitrogen was passed to degassed the system. Thereby ensuring sterility of the test system. In the preliminary test (tier 1) sampling was performed at a minimum: 0 hours, 2.4, 4, 6, 24, 48, 74, 96 and 120 hours (as appropriate depending on results). 1 mL of each sample was diluted with 2 mL of acetone. 1 μL aliquots of the test solutions at each pH value were analysed by Gas Chromatography (GC) in duplicate. For standards: Duplicate standard solutions of test material were prepared in acetone at a nominal concentration of 400.2 μg/mL. Calibration was performed by dilutions of stock solution in acetone at 0.10005 μg/mL to 100.05 μg/mL. External calibration by Gas Chromatography (GC) was performed in duplicate. Under the conditions of the study, the degradation at 50°C after 5 days was less than 10%. Therefore the test item is considered hydrolytically stable.

Description of key information

Hydrolysis: < 10% degradation after 5 days at 50°C and pH 4, 7 and 9; half-life for hydrolysis: > 365 days, at 25 °C, 1 atm, EU Method C.7, 2009

Key value for chemical safety assessment

Half-life for hydrolysis:

365 d

at the temperature of:

25 °C

Additional information

Key study : EU Method C.7, 2009 : The test followed a method in accordance with EU Method C.7 (abiotic degradation: hydrolysis as a function of pH) and OECD TG 111 under GLP serving as both a screening study (tier 1) for the hydrolysis properties of the item. The pH 4, 7 and 9 buffer solutions were sterilized for 25 minutes in an autoclave prior to first use. Nitrogen was passed through the buffer solutions for 5 minutes except when freshly sterilized. The study was conducted with the test vessels protected from light. 46.01 to 57.45 mg of test item were dissolved in 2 mL of acetone with aid of sonication and diluted with buffer solution (pH 4.0, 7.0 or 9.0) to a volume of 100 mL to prepare a stock solution of 460.1 to 574.5 μg/mL (dependent on pH). The solution submitted to a 0.2 μm filtration. To obtain a test solution of not more than half the water solubility, 50 mL the solution were diluted to a volume of 100 mL with the respective buffer. Two aliquots of this test solution of approximately 50 mL each were transferred into 50 mL flasks in duplicate. Nitrogen was passed to degassed the system. Thereby ensuring sterility of the test system. In the preliminary test (tier 1) sampling was performed at a minimum: 0 hours, 2.4, 4, 6, 24, 48, 74, 96 and 120 hours (as appropriate depending on results). 1 mL of each sample was diluted with 2 mL of acetone. 1 μL aliquots of the test solutions at each pH value were analysed by Gas Chromatography (GC) in duplicate. For standards: Duplicate standard solutions of test material were prepared in acetone at a nominal concentration of 400.2 μg/mL. Calibration was performed by dilutions of stock solution in acetone at 0.10005 μg/mL to 100.05 μg/mL. External calibration by Gas Chromatography (GC) was performed in duplicate. Under the conditions of the study, the degradation at 50°C after 5 days was less than 10%. Therefore the test item is considered hydrolytically stable.