2-Chloro-5-chloromethylpyridine

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

GLP compliance:

yes (incl. QA statement)

Radiolabelling:

no

Analytical monitoring:

yes

Buffers:

pH4:
21.008 g citric acid monohydrat were dissolved in 200 ml sodium hydroxide solution (c = 1 mol/l). This solution were filled up to a volume of 1000 ml with distilled water. 44 ml of hydrochloric acid (c = 1 mol/l) was added to 560 ml of this solution and filled up to a volume of 1000 ml with distilled water. The solution was adjusted to pH 4,0 with sodium hydroxide or hydrochloric acid.

pH7:
13.61 g potassium dihydrogen phosphate were dissolved in 1000 ml distilled water. 29.63 ml of sodium hydroxide solution (c = 1 mol/l) were added to 500 ml of this solution and filled up to a volume of 1000 ml with distilled water. The solution was adjusted to pH 7.0 with sodium hydroxide or hydrochloric acid.

pH9:
7.46 g potassium chloride and 6.184 g boric acid were dissolved in 1000 ml distilled water. 500 ml of this solution were added to 21.30 ml sodium hydroxide (c = 1 mol/l) and filled up to a volume of 1000 ml with water. The solution was adjusted to pH 9.0 with sodium hydroxide or hydrochloric acid.

Details on test conditions:

In a pretest it was determined that the decomposition at 50°C is below 50 % after 2.4 hours and higher than 10 % after 5 d for the pH 4, pH 7 and pH 9 values. According to the guideline the pretests at pH 4, pH 7 and pH 9 indicate that an examination of the hydrolysis kinetics is essential. Thus a full test was performed.

Duration:

28.25 h

pH:

4

Temp.:

50 °C

Initial conc. measured:

109.5 mg/L

Duration:

24 h

pH:

4

Temp.:

55 °C

Initial conc. measured:

110.2 mg/L

Duration:

8 h

pH:

4

Temp.:

65 °C

Initial conc. measured:

107.3 mg/L

Duration:

32 h

pH:

7

Temp.:

50 °C

Initial conc. measured:

104.7 mg/L

Duration:

24 h

pH:

7

Temp.:

55 °C

Initial conc. measured:

104.6 mg/L

Duration:

8 h

pH:

7

Temp.:

65 °C

Initial conc. measured:

108 mg/L

Duration:

40 h

pH:

9

Temp.:

50 °C

Initial conc. measured:

112.9 mg/L

Duration:

24 h

pH:

9

Temp.:

55 °C

Initial conc. measured:

105 mg/L

Duration:

16 h

pH:

9

Temp.:

65 °C

Initial conc. measured:

105.7 mg/L

Preliminary study:

In a pretest it was determined that the decomposition at 50°C is below 50 % after 2.4 hours and higher than 10 % after 5 d for the pH 4, pH 7 and pH 9 values. According to the guideline the pretests at pH 4, pH 7 and pH 9 indicate that an examination of the hydrolysis kinetics is essential. Thus a full test was performed.

Transformation products:

not specified

pH:

4

Temp.:

50 °C

Hydrolysis rate constant:

0.04 h-1

DT50:

19.72 h

pH:

4

Temp.:

55 °C

Hydrolysis rate constant:

0.06 h-1

DT50:

11.53 h

pH:

4

Temp.:

65 °C

Hydrolysis rate constant:

0.16 h-1

DT50:

4.35 h

pH:

7

Temp.:

50 °C

Hydrolysis rate constant:

0.03 h-1

DT50:

20.55 h

pH:

7

Temp.:

55 °C

Hydrolysis rate constant:

0.06 h-1

DT50:

11.71 h

pH:

7

Temp.:

65 °C

Hydrolysis rate constant:

0.16 h-1

DT50:

4.26 h

pH:

9

Temp.:

50 °C

Hydrolysis rate constant:

0.02 h-1

DT50:

28.5 h

pH:

9

Temp.:

55 °C

Hydrolysis rate constant:

0.04 h-1

DT50:

15.62 h

pH:

9

Temp.:

65 °C

Hydrolysis rate constant:

0.12 h-1

DT50:

5.6 h

Details on results:

At pH 4 the half-life period was determined by extrapolating the results of the experiments at 50 °C, 55 °C and 65 °C to a temperature of 25°C. It was found to be 14.1 days.
At pH 7 the half-life period was determined by extrapolating the results of the experiments at 50 °C, 55 °C and 65 °C to a temperature of 25°C. It was found to be 16.4 days.
At pH 9 the half-life period was determined by extrapolating the results of the experiments at 50 °C, 55 °C and 65 °C to a temperature of 25°C. It was found to be 24.9 days.

Conclusions:

The objective of this study was the determination of the abiotic degradation of the test item (the main compound), i.e. the determination of the hydrolysis rate as a function of the pH-value according to guideline 92/69/EEC, appendix, C.7 and OECD 111.
At pH 4 the half-life period was determined by extrapolating the results of the experiments at 50 °C, 55 °C and 65 °C to a temperature of 25°C. It was found to be 14.1 days.
At pH 7 the half-life period was determined by extrapolating the results of the experiments at 50 °C, 55 °C and 65 °C to a temperature of 25°C. It was found to be 16.4 days.
At pH 9 the half-life period was determined by extrapolating the results of the experiments at 50 °C, 55 °C and 65 °C to a temperature of 25°C. It was found to be 24.9 days.

Executive summary:

The objective of this study was the determination of the abiotic degradation of the test item (the main compound), i.e. the determination of the hydrolysis rate as a function of the pH-value according to guideline 92/69/EEC, appendix, C.7 and OECD 111.

At pH 4 the half-life period was determined by extrapolating the results of the experiments at 50 °C, 55 °C and 65 °C to a temperature of 25°C. It was found to be 14.1 days.

At pH 7 the half-life period was determined by extrapolating the results of the experiments at 50 °C, 55 °C and 65 °C to a temperature of 25°C. It was found to be 16.4 days.

At pH 9 the half-life period was determined by extrapolating the results of the experiments at 50 °C, 55 °C and 65 °C to a temperature of 25°C. It was found to be 24.9 days.

Description of key information

The objective of this study was the determination of the abiotic degradation of the test item (the main compound), i.e. the determination of the hydrolysis rate as a function of the pH-value according to guideline 92/69/EEC, appendix, C.7 and OECD 111.

At pH 4 the half-life period was determined by extrapolating the results of the experiments at 50 °C, 55 °C and 65 °C to a temperature of 25°C. It was found to be 14.1 days.

At pH 7 the half-life period was determined by extrapolating the results of the experiments at 50 °C, 55 °C and 65 °C to a temperature of 25°C. It was found to be 16.4 days.

At pH 9 the half-life period was determined by extrapolating the results of the experiments at 50 °C, 55 °C and 65 °C to a temperature of 25°C. It was found to be 24.9 days.

Key value for chemical safety assessment

Half-life for hydrolysis:

16.4 d

at the temperature of:

25 °C