2-(2-(4-methyl-3-cyclohexen-1-yl)propyl)cyclopentanone

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

04 April 1995 through 05 May 1995

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

Specific details on test material used for the study:

NECTARYL :
- Lot No. : 001143
- Purity : Matches Standard

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

Preliminary Test :
A preliminary test was conducted at 50°C at pH4, 7 and 9.
Samples were taken at Time 0, 2.4 hours, 24 hours and 120 hours and analysed by HPLC.
Nectaryl was observed to be stable at pH7 and pH9. A decrease of 17%, c.f. Time 0, was observed in the pH4 buffer solution. pH4 buffer was, thus, studied in more detail.

pH4 - Test 1 at 50°C :
Samples taken at Time 0, 2.4 hours, 24 hours, 120 hours, 360 hours and 650 hours.

A further test (Test 2) was conducted at 70°C at pH4 :
Sampling times : 0, 24, 96, 169 and 288 hours.

Buffers:

Ready-made concentrates (Titrisol, Merck, Darmstadt, DE) were used to prepare the buffer solutions using fresh double-distilled, sterile water.

pH4.00 +/- 0.02 at 20°C : Citric Acid 0.056 mole/L, NaOH 0.11 mol/L, HCl 0.044 mol/L

pH7.00 +/- 0.02 at 20 °C : KH2PO4 0.026 mole/L, Na2HPO4 0.041 mole/L

pH9.00 +/- 0.02 at 20 °C : H3BO3 0.05 mole/L, KCl 0.05 mole/L, NaOH 0.022 mole/L

Details on test conditions:

Test Substance Solution :
A test concentration of 2.4 mg/L was chosen for the study (i.e. 50% of the water solubility).
A stock solution of 240 mg/L of Nectaryl in CH3CN was prepared

Preliminary Test :
Performed at 50 °C.
For each of pH4, 7 and 9, the following operations were performed simultaneously :
- a 250 mL amber glass bottle was filled with 250 mL of the respective buffer solution;
- N2 is bubbled for 5 minutes to remove residual dissolved O2;
- the flask is placed in a water bath at 50 °C;
- 2.5 mL of NECTARYL stock solution added and mixed;
- a 10 mL sample is withdrawn through the stopcock and temperature and pH measured then analysed via HPLC-UV/VIS.
- subsequent sampling after 2.4, 24 and 120 hours of incubation at 50 °C.

No degradation observed for pH7 and pH9.

The incubation for the pH4 incubate was extended and samples taken at :
- 360 and 650 hours.

A second test at pH4 was performed at a temperature of 70 °C :
- Run in duplicate samples;
- Samples taken and analysed at Time 0, 24, 96, 169 and 288 hours;
- Samples analysed by HPLC-UV/VIS.

Duration:

120 h

pH:

4

Temp.:

50 °C

Initial conc. measured:

2.22 mg/L

Remarks:

Test item concn determined at 120 hours = 1.84 mg/L

Duration:

120 h

pH:

7

Temp.:

50 °C

Initial conc. measured:

2.3 mg/L

Remarks:

Test item concn determined at 120 hours = 2.20 mg/L

Duration:

120 h

pH:

9

Temp.:

50 °C

Initial conc. measured:

2.35 mg/L

Remarks:

Test item concn determined at 120 hours = 2.27 mg/L

Number of replicates:

Preliminary Test :
pH4 : 1 sample
pH7 : in duplicate
pH9 : 1 sample

pH4 at 70 °C :
In duplicate.

Positive controls:

no

Negative controls:

no

Preliminary study:

Preliminary Test :
A preliminary test was conducted at 50°C at pH4, 7 and 9.
Samples were taken at Time 0, 2.4 hours, 24 hours and 120 hours and analysed by HPLC.
Nectaryl was observed to be stable at pH7 and pH9. A decrease of 17%, c.f. Time 0, was observed in the pH4 buffer solution. pH4 buffer was, thus, studied in more detail.

Transformation products:

no

% Recovery:

83

pH:

3.84

Temp.:

50 °C

Duration:

120 h

Remarks on result:

other: Need to continue to additional testing at pH4

% Recovery:

96

pH:

6.85

Temp.:

50 °C

Duration:

120 h

Remarks on result:

other: Less than 10% degradation observed at 50 °C, T1/2 considered > 1-year at 25°C.

% Recovery:

97

pH:

8.69

Temp.:

50 °C

Duration:

120 h

Remarks on result:

other: Less than 10% degradation observed at 50 °C, T1/2 considered > 1-year at 25°C.

% Recovery:

42

pH:

3.84

Temp.:

50 °C

Duration:

650 h

% Recovery:

10.5

pH:

4

Temp.:

70 °C

Duration:

288 h

Key result

pH:

4

Temp.:

25 °C

Hydrolysis rate constant:

0 h-1

DT50:

210 d

Type:

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

Key result

pH:

7

Temp.:

25 °C

DT50:

> 1 yr

Key result

pH:

9

Temp.:

25 °C

DT50:

> 1 yr

Validity criteria fulfilled:

yes

Conclusions:

Nectaryl undergoes negligible hydrolysis at pH7 and pH9 (T1/2 > 1 year at 25 °C), whereas a normal pseudo-1st order hydrolysis reaction occurs at pH4 with a derived half-life time of 210 days at 25 °C.

Executive summary:

Nectaryl undergoes negligible hydrolysis at pH7 and pH9 (T1/2 > 1 year at 25 °C), whereas a normal pseudo-1st order hydrolysis reaction occurs at pH4 with a derived half-life time of 210 days at 25 °C.

Description of key information

Nectaryl undergoes negligible hydrolysis at pH7 and pH9 (T1/2 > 1 year at 25 °C), whereas a normal pseudo-1st order hydrolysis reaction occurs at pH4 with a derived half-life time of 210 days at 25 °C.

Key value for chemical safety assessment

Half-life for hydrolysis:

1 yr

at the temperature of:

25 °C