Allyl 3-cyclohexylpropionate

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2012-06-20 to 2012-12-10

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)

Deviations:

no

GLP compliance:

yes

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

- Sampling intervals for the parent products: in the main test, samples were taken after 0, 2, 4, 6, 8, 24 and 26 hours at 50 °C, after 0, 2.5, 4.5, 22.5, 25, 27.5, 47 and 52 hours at 40 °C and after 0, 3.5, 23, 27, 48, 54, 73, 77, 98 and 102 hours at 30 °C under all pH conditions
- Sampling method: test flasks containing the sample solutions were taken from the water bath at various times
- Sampling intervals/times for pH measurements: the pH value of each sampled solution was recorded
- Sampling intervals/times for sterility check: not performed
- Sample storage conditions before analysis: it was not reported that samples were stored before analysis

Buffers:

- pH 4: buffer solution was prepared from citric acid (12 mmol/dm3), sodium chloride (9 mmol/dm3) and sodium hydroxide (14 mmol/dm3)
- pH 7: buffer solution was prepared from disodium hydrogen orthophosphate (anhydrous, 6 mmol/dm3), potassium dihydrogen orthophosphate (4 mmol/dm3) and sodium chloride (4 mmol/dm3)
- pH 9: buffer solution was prepared from disodium tetraborate (2 mmol/dm3) and sodium chloride (4 mmol/dm3)

Details on test conditions:

TEST SYSTEM
- System: distilled water
- Type, material and volume of test flasks, other equipment used: stoppered glass flasks
- Sterilisation method: not reported
- Lighting: not reported
- Measures taken to avoid photolytic effects: incubation in the dark
- Measures to exclude oxygen: degassing with nitrogen to minimise dissolved oxygen content
- Details on test procedure for unstable compounds: none
- Details of traps for volatile, if any: none
- If no traps were used: closed system was used
- there was no evidence that the substance adsorbed to the walls of the flask

TEST MEDIUM
- Volume used/treatment: not reported
- Kind and purity of water: not reported
- Preparation of test medium: substance was dissolved in water
- Identity and concentration of co-solvent: 1% co-solvent of methanol

OTHER TEST CONDITIONS
- Adjustment of pH: none
- Dissolved oxygen: not reported

Duration:

26 h

pH:

4

Temp.:

50 °C

Initial conc. measured:

4.7 - 4.8 mg/L

Duration:

52 h

pH:

4

Temp.:

40 °C

Initial conc. measured:

4.43 - 4.52 mg/L

Duration:

102 h

pH:

4

Temp.:

30 °C

Initial conc. measured:

4.74 - 4.78 mg/L

Duration:

26 h

pH:

7

Temp.:

50 °C

Initial conc. measured:

4.73 - 4.77 mg/L

Duration:

52 h

pH:

7

Temp.:

40 °C

Initial conc. measured:

4.59 - 4.66 mg/L

Duration:

123 h

pH:

7

Temp.:

30 °C

Initial conc. measured:

5.11 - 5.14 mg/L

Duration:

26 h

pH:

9

Temp.:

50 °C

Initial conc. measured:

4.33 - 4.64 mg/L

Duration:

52 h

pH:

9

Temp.:

40 °C

Initial conc. measured:

4.44 - 4.77 mg/L

Duration:

123 h

pH:

9

Temp.:

30 °C

Initial conc. measured:

4.71 - 4.73 mg/L

Number of replicates:

One sample per time point per pH value per temperature

Positive controls:

no

Negative controls:

no

Preliminary study:

Greater than 10% hydrolysis was observed after 120 hours at all pH values at 50 °C test temperature triggering a tier 2 assessment.

Transformation products:

not measured

No.:

#1

No.:

#2

Key result

pH:

4

Temp.:

25 °C

Hydrolysis rate constant:

0.008 h-1

DT50:

90.5 h

Type:

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

Key result

pH:

7

Temp.:

25 °C

Hydrolysis rate constant:

0.008 h-1

DT50:

90.8 h

Type:

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

Key result

pH:

9

Temp.:

25 °C

Hydrolysis rate constant:

0.013 h-1

DT50:

51.4 h

Type:

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

Other kinetic parameters:

not specified

Details on results:

TEST CONDITIONS
- pH, sterility, temperature, and other experimental conditions maintained throughout the study: Yes
- Anomalies or problems encountered: none

MAJOR TRANSFORMATION PRODUCTS
Based on the structure it is anticipated that the transformation products of the hydrolysis reaction are allyl alcohol and cyclohexylpropionic acid

INDICATION OF UNSTABLE TRANSFORMATION PRODUCTS: none

VOLATILIZATION (at end of study): not reported

PATHWAYS OF HYDROLYSIS: not reported

Validity criteria fulfilled:

yes

Conclusions:

The substance was hydolysed under all tested pH conditions with a tendency of more rapid hydrolysis at basic pH values.

Executive summary:

The hydrolysis of the substance allyl cyclohexylpropionate was tested under GLP in accordance with OECD TG 111. First, a preliminary test was undertaken, in which sample solutions were maintained at 50 °C ± 0.5 °C for a period of 24 hours. The results from this preliminary test showed that it was necessary to conduct a main test at pH 4, pH 7 and pH 9 with solutions being maintained at 50, 40 and 30 °C. In the main test, sample solutions were taken from the tempered waterbaths at various time points, the pH of each solution was recorded and the concentration of the test substance was determined by gas chromatography. To this end, duplicate aliquots of each sample were extracted with dichloromethane, each extract being filtered through anhydrous sodium phosphate and spiked with an internal standard. The kinetics of the hydrolysis reaction has been determined to be consistent with that of a pseudo-first order reaction. The rate constant and half-life of hydrolysis at 25 °C was determined from the experimental data by the use of the Arrhenius relationship. The estimated rate constants at 25 °C were 0.00766 hr-1 at pH 4, 0.00764 hr-1 at pH 7 and 0.0135 hr-1 at pH 9, which corresponds to half-lives of 90.5, 90.8 and 51.4 hours, respectively.

Description of key information

The substance was found to rapidly hydrolyse under environmental conditions. The hydrolysis reaction followed pseudo-first order reaction kinetics. It was observed that more rapid hydrolysis occurred under more alkaline reaction conditions.

Key value for chemical safety assessment

Half-life for hydrolysis:

90.8 h

at the temperature of:

25 °C

Additional information

A valid hydrolysis study in accordance with OECD TG 111 was conducted. The results of a preliminary test indicated that further testing is required and the hydrolysis was studied in a main test at pH 4, pH 7 and pH 9 with sample solutions being maintained at 30 °C, 40 °C or 50 °C. It was found that the substance was hydrolysed under all test conditions and that the reaction followed pseudo-first order kinetics. The rate constants for the reaction at 25 °C were estimated by using the Arrhenius relationship and were 0.00766 hr-1 at pH 4, 0.00764 hr-1 at pH 7 and 0.0135 hr-1 at pH 9. This corresponds to half-lives of 90.5 hours, 90.8 hours and 51.4 hours, respectively. This shows that the substance is rapidly degraded under environmental conditions.

 

Based on the chemical structure of the test item, the test item was considered to hydrolyze at the ester functional group to give Allyl alcohol and Cyclohexylpropionic acid.