Cyclohexanone, 4-methoxy-

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2006-04-19 to 2006-09-05

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)

Version / remarks:

1992

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Version / remarks:

2004

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

Test samples of the test item were prepared by pipetting 10 mL of the respective diluted stock solution in duplicate into crimp-top vials, subsequently overlaid with nitrogen and hermetically sealed. The resulting test samples were subjected immediately to the hydrolysis procedure. The crimp caps of the samples were marked to distinguish duplicate samples and pH values.

Buffers:

Buffer pH 4:
21.008 g citric acid monohydrate were dissolved in 200 mL of sodium hydroxide solution(c = 1 mol/L). This solution was made up to a volume of 1000 mL using distilled water. 44 mL of aqueous hydrochloric acid (c = 1 mol/L) was added to 560 mL of this solution and made up to a volume of 1000 mL with distilled water. The solution was adjusted to pH 4.0 using aqueous sodium hydroxide or hydrochloric acid.

Buffer pH 7:
13.61 g potassium dihydrogene phosphate were dissolved in 1000 mL of distilled water. 29.63 mL of sodium hydroxide solution (c = 1 mol/L) were added to 500 mL of this solution and made up to a volume of 1000 mL using distilled water. The solution was adjusted to pH 7.0 using aqueous sodium hydroxide or hydrochloric acid.

Buffer pH 9:
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 solution (c = 1 mol/L) and made up to a volume of 1000 mL using water. The solution was adjusted to pH 9.0 with aqueous sodium hydroxide or hydrochloric acid.

Number of replicates:

One replicate at each pH plus one control.

Negative controls:

yes

Preliminary study:

At pH 4, pH 7 and pH 9 less than 10 % of the test item decomposed within 5 days at 50 °C. Thus, the test item may be considered hydrolytically stable at all three pH values.

According to Guideline 92/69/EEC a half-life period of more than one year under environmental conditions (25 °C) may be estimated.

Transformation products:

no

pH:

4

Temp.:

25 °C

DT50:

> 1 yr

Type:

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

Key result

pH:

7

Temp.:

25 °C

DT50:

> 1 yr

Type:

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

pH:

9

Temp.:

25 °C

DT50:

> 1 yr

Type:

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

At pH 4, pH 7 and pH 9 less than 10 % of the test item decomposed within 5 days at 50 °C. Thus, the test item may be considered hydrolytically stable at all three pH values. According to Guideline 92/69/EEC a half-life period of more than one year under environmental conditions (25 °C) may be estimated. Considering this, the pre-tests at pH 4, pH 7 and pH 9 indicate that an examination of further kinetics is not necessary.

 

Validity criteria for the measurement of the hydrolysis:

Target condition according to guideline:	Actual condition according to the study:	Validity criteria met:
The analytical method must be sufficiently precise and sensitive to detect a reduction of 10 % of the initial concentration.	HPLC-UV was used for the analytical measurement.	Yes
If the preliminary test indicates that 50 % or more of the test substance has been hydrolyzed in 2,4 hours at 50 °C, or less than 10 % has been hydrolyzed after five days at each of the three pH values (4, 7 and 9 ), no further testing is necessary.	In the preliminary test: at pH 4, pH 7 and pH 9 less than 10 % of the test item decomposed within 5 days at 50 °C. days at 50 °C. Thus, the test item may be considered hydrolytically stable at all three pH values. According to Guideline 92/69/EEC a half-life period of more than one year under environmental conditions (25 °C) may be estimated.	Yes
For each test: the temperature, pH value, buffer composition and a table of all concentration-time data points shall be stated.	pH values, buffers used and a table of concentration at the measured time points is given in the study report.	Yes

 

Validity criteria fulfilled:

yes

Remarks:

See 'Any other information on results incl. tables'.

Conclusions:

At 25 °C according to the guideline a half-life period of above one year at pH 4, pH 7 and pH 9 may be estimated.

Executive summary:

At pH 4, pH 7 and pH 9 less than 10 % of the test item decomposed within 5 days at 50 °C. Thus, the test item may be considered hydrolytically stable at all three pH values. According to Guideline 92/69/EEC a half-life period of more than one year under environmental conditions (25 °C) may be estimated.

 

 

pH value	Half life (25°C)
4	> 1 year
7	> 1 year
9	> 1 year

 

Description of key information

At pH 4, pH 7 and pH 9 less than 10 % of the test item decomposed within 5 days at 50 °C. Thus, the test item may be considered hydrolytically stable at all three pH values. According to Guideline 92/69/EEC a half-life period of more than one year under environmental conditions (25 °C) may be estimated.

Key value for chemical safety assessment

Half-life for hydrolysis:

1 yr

at the temperature of:

25 °C