3,9-dicyclohex-3-enyl-2,4,8,10-tetraoxaspiro[5.5]undecane

Hydrolysis

Administrative data

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2012-08-29 till 2012-12-06

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Principles of method if other than guideline:

The hydrolysis behaviour of the test item 3,9-Di-3-cyclohexen-1-yl-2,4,8,10-tetraoxaspiro-[5.5]undecane was investigated at 50 °C and pH 4, pH 7 and pH 9 over a period of 35 days according to OECD TG 111. The stability was monitored by HPLC analysis using MS-MS detection.

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

3,9-dicyclohex-3-enyl-2,4,8,10-tetraoxaspiro[5.5]undecane

EC Number:

229-542-8

EC Name:

3,9-dicyclohex-3-enyl-2,4,8,10-tetraoxaspiro[5.5]undecane

Cas Number:

6600-31-3

Molecular formula:

C19H28O4

IUPAC Name:

3,9-bis(cyclohex-3-en-1-yl)-2,4,8,10-tetraoxaspiro[5.5]undecane

Constituent 2

Reference substance name:

Vulkazon AFS

IUPAC Name:

Vulkazon AFS

Test material form:

other: granules

Details on test material:

- Purity: 96.7 %
- Empirical formula: C19H28O4
- Molecular mass: 320.4 g/mole

Radiolabelling:

no

Study design

Analytical monitoring:

yes

Details on sampling:

Immediately after preparation of the test solutions and after defined time intervals, samples were taken and analyzed by HPLC.

Buffers:

Buffer pH 4, Fa. Fluka, Citric acid/NaOH/NaCl, Art-Nr.: 33643
Buffer pH 7, Fa. Fluka, KH2PO4/Na2HPO4, Art-Nr.: 33646
Buffer pH 9, Fa. Fluka, Na2B4O7/HCl, Art-Nr.: 33648

Details on test conditions:

Stock solutions of the test item were prepared by weighting of approx. 21 mg of the test item in 100 mL acetonitrile.
Separate hydrolysis test solutions for each pH were prepared by 1:400 dilution of the stock solution with the corresponding buffer systems. Aliquots of these hydrolysis test solutions were taken without further treatment to obtain individual vials for every test point.

pH 4 at 50 °C:
20.7 mg of the test item 3,9-Di-3-cyclohexen-1-yl-2,4,8,10-tetraoxaspiro[5.5]-undecane were dissolved in 100 mL acetonitrile. These stock solutions were 1:400 diluted with buffer solution pH 4, leading to a test item concentration of 500.4 μg/L.
pH 7 at 50 °C:
20.7 mg of the test item 3,9-Di-3-cyclohexen-1-yl-2,4,8,10-tetraoxaspiro[5.5]-undecane were dissolved in 100 mL acetonitrile. These stock solutions were 1:400 diluted with buffer solution pH 7, leading to a test item concentration of 500.4 μg/L.
pH 9 at 50 °C:
20.7 mg of the test item 3,9-Di-3-cyclohexen-1-yl-2,4,8,10-tetraoxaspiro[5.5]-undecane were dissolved in 100 mL acetonitrile. These stock solutions were 1:400 diluted with buffer solution pH 9, leading to a test item concentration of 500.4 μg/L.

Aliquots of the stock solution were taken to obtain individual vials for every test point. Preparation was carried out under nitrogen as flushing gas, to avoid oxygen.
The vials were closed and incubated at 50 °C in a heat regulator under dark to avoid any photolytic effects.
The pH of the blank buffer solution was checked at the beginning of the test. Additionally the pH of the hydrolysis solution was measured at each test point. The temperature during the experiment was also checked at each test point.
Calibration was done at each point in time at the defined time intervals for the analysis of the hydrolysis test solution. The calibration was verified by comparing the HPLC-MS areas of the calibration solution.
At each test point the hydrolysis solution was directly led to the chromatographic measurement.

Duration of test

Duration:

635 h

pH:

4

Temp.:

50 °C

Initial conc. measured:

500.4 µg/L

Positive controls:

no

Negative controls:

no

Results and discussion

Preliminary study:

Pre-tests for hydrolysis
According to OECD TG 111 the concentration of the test item should not exceed 0.01 M or half of the saturation concentration of the water solubility. The test item was applied as an aqueous solution (including 1 % acetonitrile) with a concentration of approx. 0.5 mg/L (0.0016 mole/L) which fulfills the requirements of OECD TG 111. In compliance with OECD 111 Guideline no further solubility test with organic solvent additives > 1 % v/v was performed.

Transformation products:

yes

Identity of transformation products

Identity of transformation products 1

No.:

#1

Reference

Reference substance name:

Unnamed

IUPAC name:

(2-cyclohex-3-en-1-yl-1,3-dioxane-5,5-diyl)dimethanol

Identifier:

other: Chemical name

Identity:

(2-cyclohex-3-en-1-yl-1,3-dioxane-5,5-diyl)dimethanol

Identity of transformation products 2

No.:

#2

Reference

Reference substance name:

Unnamed

IUPAC name:

pentaerythritol

Inventory number:

InventoryMultipleMappingImpl [inventoryEntryValue=EC 204-104-9]

CAS number:

115-77-5

Details on hydrolysis and appearance of transformation product(s):

#1: (2-cyclohex-3-en-1-yl-1,3-dioxane-5,5-diyl)dimethanol, molecular formula = C12H20O4, formula weight = 228 g/mole
#2: 115-77-5 = pentaerythritol, molecular formula = C5H12O4, formula weight = 136 g/mole

Total recovery of test substance (in %)

Total recovery of test substance (in %) 1

% Recovery:

30.4

pH:

4

Temp.:

50 °C

Duration:

35 d

Total recovery of test substance (in %) 2

% Recovery:

83.4

pH:

7

Temp.:

50 °C

Duration:

35 d

Total recovery of test substance (in %) 3

% Recovery:

85.4

pH:

9

Temp.:

50 °C

Duration:

35 d

Dissipation DT50 of parent compound

pH:

4

Temp.:

50 °C

DT50:

635 d

Type:

other: k = 3.03 x 10-7 /s

Details on results:

Recovery, repeatability:
The recovery and the repeatability were checked during the hydrolysis study by analyzing the calibration solution. Calibration was done at each point in time at the defined time intervals for the analysis of the hydrolysis test solution. The calibration was verified by comparing the HPLC-MS areas of the calibration solutions.

Result:
Results of the solutions for verification of the calibration show stability of the chromatographic system. Recoveries of the test item are near 100 % indicating a satisfying repeatability of the method applied to quantify the test item concentrations. The requirements of OECD 111 are met.

Sensitivity:
Regarding the chromatogram of the lowest concentration of 50.04 μg/L used for calibration, the analytical method is sufficiently sensitive to quantify test item concentrations down to 10 % or less of the initial concentration used in the hydrolysis experiment.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

Results of the solutions for verification of the calibration show stability of the chromatographic system. Recoveries of the test item are near 100 % indicating a satisfying repeatability of the method applied to quantify the test item concentrations.

Conclusions:

The hydrolysis of the test item showed an abiotic degradation and considered that the substance is to be hydrolytically unstable at 50 °C for pH-value 4.The half-life time and hydrolysis rate constant were calculated (mean value of two determinations) at t1/2 = 635 hours and the hydrolysis rate constant at k = 3.03*10-7/s.
The test substance is stable at 50 ° C and the pH values ​​of 7 and 9, because no abiotic degradation was observed. Therefore it can assumed that the substance is also stable at 25 °C and no half-life times and hydrolysis rates were calculated.

Executive summary:

The hydrolysis behaviour of the test item were performed to OECD Guideline for Testing of Chemicals, Section 1 – Physical-Chemical Properties, OECD TG 111 (2004) and the EU Method C.7 “Abiotic Degradation: Hydrolysis as a Function of pH” (adopted, May 2008). An abiotic degradation of the substance was observed and considered that the substance is to be hydrolytically unstable at 50 °C for pH-value 4. The half-life time and hydrolysis rate constant were calculated (mean value of two determinations) at t1/2 = 635 hours and the hydrolysis rate constant at k = 3.03*10-7/s.

The test item is stable at 50 ° C and the pH values ​​of 7 and 9, because no abiotic degradation was observed. Therefore it can assumed that the substance is also stable at 25 °C and no half-life times and hydrolysis rates were calculated.