1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4-(trifluoromethyl)pentane

Hydrolysis

Administrative data

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

other information

Study period:

06 - 18 Jul 2005

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

unsuitable test system

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2005

Report date:

2005

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

test discontinued at preliminary stage

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

459-520-5

EC Name:

-

Cas Number:

132182-92-4

Molecular formula:

Hill formula: C7H3F13O CAS formula: C7H3F13O

IUPAC Name:

1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4-(trifluoromethyl)pentane

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: PDC Lot 1, Pail 2
- Expiration date of the lot/batch: 23 Mar 2006
- Purity: 99.959%
- Synonyms: MTDID 665

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature in the dark

Radiolabelling:

no

Study design

Analytical monitoring:

yes

Details on sampling:

Vials were cooled with running tap water at their sample points. A 10-mL aliquot was then taken from each transferred to a 20-mL headspace vial containing ca. 1.5 g NaCl. Dichloromethane (50 µL) was then added and the vials placed in an autosampler to await analysis.

Buffers:

- pH: 4
- Type and final molarity of buffer: 0.05M sodium acetate/acetic acid in RO water

- pH: 7
- Type and final molarity of buffer: 0. 05M phosphate buffer
- Composition of buffer: potassium dihydrogen phosphate/sodium hydroxide in RO water

- pH: 9
- Type and final molarity of buffer: 0.05M borate buffer
- Composition of buffer: boric acid/potassium chloride/sodium hydroxide in RO water

Details on test conditions:

TEST SYSTEM
- Type, material and volume of test flasks, other equipment used: 20-mL glass vials completely filled to avoid headspace and sealed with a septum crimp cap owing to test substance volatility
- Sterilisation method: filtration through 0.2 µm filter
- Lighting: vials kept in darkness
- Measures to exclude oxygen: nitrogen gas bubbled through each solution for five minutes
- Is there any indication of the test material adsorbing to the walls of the test apparatus? No

TEST MEDIUM
- Volume used/treatment: ca. 20 mL
- Kind and purity of water: buffers were made in Millipore ™ reverse osmosis water.
- Preparation of test medium: buffers were filled into vials and a 50 µL aliquot of a stock solution added to start the test.
- Renewal of test solution: No. Triplicate vials were made for each time point (immediately, at 2.4 hours, and at 5 days
- Identity and concentration of co-solvent: Test substance at a stock concentration of ca 1000 g/L in methanol

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Dissolved oxygen: Oxygen excluded

Duration of test

Duration of test 1

Duration:

5 d

pH:

4

Temp.:

50 °C

Initial conc. measured:

0.172 mg/L

Duration of test 2

Duration:

5 d

pH:

7

Temp.:

50 °C

Initial conc. measured:

0.212 mg/L

Duration of test 3

Duration:

5 d

pH:

9

Temp.:

50 °C

Initial conc. measured:

0.162 mg/L

Number of replicates:

Three for each of three time points

Positive controls:

no

Remarks:

periodic validation with acetylsalicylic acid

Results and discussion

Preliminary study:

Results of the preliminary tests are depicted in the illustration. Test substance concentrations were reduced 24-33% after 2.4 hours and below LOQ by day five. Although test vessels were set up without headspace in septum-sealed glass vials, a gas phase was observed in all vials after five days at 50 °C (boiling point of test substance, 99 °C, Henry's Law constant of 67 atm∙m³/mol). From this, it was concluded that the significant decrease in concentration over time at all pH levels was a result of evaporation of the test substance from solution. The test was therefore deemed technically infeasible and a final test was not performed.

Transformation products:

no

Dissipation DT50 of parent compound

Remarks on result:

not determinable because of methodological limitations

Remarks:

Test substance is volatile and forms a separate gas phase in reaction vessels

Applicant's summary and conclusion

Conclusions:

While the test substance is too volatile to allow determination of hydrolytic rate constant, no hydrolysis is expected due to lack of hydrolytically active structiures.

Executive summary:

Hydrolysis of HFE s-601 was examined in a preliminary test done at 50 °C per EC method C.7. The test substance is known to be volatile, with a boiling point of 99 °C and a Henry's Law constant of 67 atm∙m³/mol. Significant losses were seen at all pH values at the end of the test. However, in all cases a vapor phase had developed within the vial. Since an examination of structure shows that the model does not contain hydrolyzable groups, loss in concentration over time was ascribed to evaporation of the test substance. The test was deemed technically infeasible and discontinued.

While the study was done per accepted guideline and was GLP compliant, the test substance could not be maintained in solution despite best efforts. It is deemed unreliable due to an unsuitable test system.