2-fluoro-6-trifluoromethylpyridine

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

supporting study

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

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Substance ID: F6TF
Lot #: R646899
Purity: 99.5%

Radiolabelling:

no

Analytical monitoring:

no

Buffers:

- pH: 4
- Composition of buffer: 4.0 mL of 0.1 M sodium hydroxide and 10.21 g of potassium hydrogen phthalate (MW 204.23) made up to 1000 mL with deionised water

- pH: 7
- Composition of buffer: 290 mL of 0.1 M sodium hydroxide and 6.8 g of potassium dihydrogen orthophosphate (MW 136.09) made up to 1000 mL with deionised water

- pH: 9
- Composition of buffer: 46 mL 0.1 M HCl and 4.78 g borax (Na2B4O7.10H2O, MW 381.37) made up to 1000 mL with deionised water

Details on test conditions:

Preparation of Test Solutions: Buffer solutions were prepared as described above. These buffer solutions were sterilised by autoclaving and subsequently de-oxygenated by bubbling with helium for approximately 5 minutes.

The concentration of the test substance in the test solutions was a nominal 0.90 mg/L. The test solutions were prepared by the addition of an aliquot (100 µL) of a stock solution (900 mg/L) prepared in methanol, to a known volume of the appropriate buffer solution. Due to the volatile nature of the test substance, sacrificial vessels were used for each sampling point. The vessels were 5 mL micro-reaction vessels with PTFE septa. Nine aliquots of each solution were put into the vessels, which had been covered with aluminium foil to exclude light. The pH of the bulk stock solution was recorded using a calibrated meter. All of the vials were put into an oscillating water bath, previously set to 50°C.

A preliminary test was performed on the test substance at 50 ± 0.5°C at pH 4, 7 and 9 in triplicate. If at any pH, less than 10% of the test substance was hydrolysed after 5 days, then it was considered hydrolytically stable under environmental conditions (i.e. estimated half life being ≥ 1 year at 25°C).

Samples from each flask were analysed at time 0, 2.4 hours and 5 days. The pH of the buffered solutions were measured at time 0, 2.4 hours and 5 days. The temperature in the water bath was measured at intervals throughout the study.

Duration:

5 d

pH:

4

Temp.:

50 °C

Initial conc. measured:

>= 0.9 - <= 0.94 mg/L

Duration:

5 d

pH:

7

Temp.:

50 °C

Initial conc. measured:

>= 0.88 - <= 93 mg/L

Duration:

5 d

pH:

9

Temp.:

50 °C

Initial conc. measured:

>= 0.89 - <= 0.96 mg/L

Number of replicates:

3

Preliminary study:

Hydrolysis was <10% after 5 days at pH 4, 7 and 9 and indicated that at these pHs the test substance could be considered hydrolytic ally stable under environmental conditions (i.e. estimated half life being ≥1 year at 25°C). Consequently, no additional testing was carried out.

% Recovery:

96

pH:

4

Temp.:

50 °C

Duration:

5 d

% Recovery:

92

pH:

7

Temp.:

50 °C

Duration:

5 d

% Recovery:

98

pH:

9

Temp.:

50 °C

Duration:

5 d

Details on results:

Preliminary Test: Hydrolysis was <10% after 5 days at pH 4, 7 and 9 and indicated that at these pHs the test substance could be considered hydrolytically stable under environmental conditions (i.e. estimated half life ≥ 1 year at 25ºC). No further work on a definitive test was carried out in line with the guidelines.

pH	Flask	Time 0		2.4 hrs		5 days
		Measured Concentration (mg/L)	% Nominal	Measured Concentration (mg/L)	% Nominal	Measured Concentration (mg/L)	% Nominal	% Hydrolysis
4	1	0.90	100	0.81	90	0.84	93	6.7
4	2	0.91	101	0.88	98	0.88	98	3.3
4	3	0.94	104	0.89	99	0.87	97	7.4
4	average	0.92	102	0.86	96	0.86	96	5.8
7	1	0.88	98	0.87	97	0.82	91	6.8
7	2	0.93	103	0.91	101	0.84	93	9.7
7	3	0.93	103	0.92	102	0.84	93	9.7
7	average	0.91	101	0.90	100	0.83	92	8.8
9	1	0.89	99	0.90	100	0.93	103	-4.5
9	2	0.93	103	0.90	100	0.86	96	7.5
9	3	0.96	107	0.94	104	0.86	96	10.4
9	average	0.93	103	0.91	101	0.88	98	4.7

Validity criteria fulfilled:

yes

Conclusions:

Hydrolysis was <10% after 5 days at pH 4, 7 and 9 and indicated that at these pHs the test substance could be considered hydrolytically stable under environmental conditions (i.e. estimated half life ≥ 1 year at 25 ºC).

Executive summary:

A preliminary test was performed on the test substance at approximately 50ºC at pH 4, 7 and 9 in triplicate. Hydrolysis was <10% after 5 days at pH 4, 7 and 9 and indicated that at these pHs the test substance could be considered hydrolytically stable under environmental conditions (i.e. estimated half life ≥1 year at 25 ºC). No further work on a definitive test was carried out in line with the guidelines.

Description of key information

Hydrolysis was <10% after 5 days at pH 4, 7 and 9 indicating that the test substance could be considered hydrolytically stable under environmental conditions (estimated half life ≥ 1 year at 25 ºC).

Key value for chemical safety assessment

Half-life for hydrolysis:

1 yr

at the temperature of:

25 °C