Registration Dossier

Environmental fate & pathways

Hydrolysis

Currently viewing:

Administrative data

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
Reason / purpose for cross-reference:
reference to other study
Qualifier:
according to guideline
Guideline:
OECD Guideline 111 (Hydrolysis as a Function of pH)
Version / remarks:
2004
GLP compliance:
no
Remarks:
Although this study is non-GLP, the laboratory used is proficient and is capable of performing studies in compliance with GLP. This study was conducted for the purposes of other regulatory jurisdications where GLP is not a mandatory requirement.
Radiolabelling:
no
Analytical monitoring:
yes
Details on sampling:
Test was conducted until 6 points were taken between 10% and 90% hydrolysis of the test substance or for 30 days. At sampling dates, 0.6mL was sampled from test solution and filtered by Millex-LG (0.2um, Merck).
Filtrates were analysed by IC. The samples were immediately analysed after sampling.
Details of sampling intervals are presented in table 1 below.
Buffers:
pH 4.0: Mixture of 4.0mL of 0.1N NaOH and 500mL of 0.1M Potassium hydrogen phthalate was diluted to 1000 mL with ultra-pure water.
pH 7.0: Mixture of 296mL of 0.1N NaOH and 500 mL of 0.1 M KH2PO4 was diluted to 1000 mL with ultra-pure water
pH 9.0: Mixture of 213 mL of 0.1N NaOH and 500 mL of 0.1M KCl/0.1M H3BO3 was diluted to 100 mL with ultra-pure water
Details on test conditions:
Temperature: 3 temperatures (15, 40 and 50°C)
Duration: Test was conducted until 6 points were taken between 10 and 90% hydrolysis of the test substance or for 30 days.
Test conducted in dark conditions
Concentration 100 mg/L

Procedure:
The test substance was weighed (30 mg) and dissolved in 300 mL of buffer solutions (pH 4, 7 and 9). Vessels were duplicated and the initial pH (measured values) were 4, 7 and 8.9. The solutions were stirred in an incubator at 15°C, or shaken in the thermostatic water bath at 40 and 50°C.
Duration:
30 d
pH:
4
Temp.:
15 °C
Duration:
30 d
pH:
4
Temp.:
40 °C
Duration:
30 d
pH:
4
Temp.:
50 °C
Duration:
30 d
pH:
7
Temp.:
15 °C
Duration:
16 d
pH:
7
Temp.:
40 °C
Duration:
10 d
pH:
7
Temp.:
50 °C
Duration:
16 d
pH:
9
Temp.:
15 °C
Duration:
1 d
pH:
9
Temp.:
40 °C
Duration:
0 d
pH:
9
Temp.:
50 °C
Number of replicates:
2
Positive controls:
not specified
Negative controls:
not specified
Preliminary study:
Hydrolysis of the test substance was seen in the preliminary study at greater than 10% therefore full study (Tier 2 and Tier 3) required
Test performance:
Tier 2: calculation of rate of hydroysis and half-lifes
Tier 3: identification of transformation (hydrolysis) products
Transformation products:
yes
No.:
#1
No.:
#2
No.:
#3
Details on hydrolysis and appearance of transformation product(s):
The final measurement of each test (7th measurement), the hydrolysis products were quantitatively measured (see tables 2 - 6)
% Recovery:
>= 91 - <= 95
pH:
4
Temp.:
15 °C
Duration:
>= 719.8 - <= 721.8 h
% Recovery:
ca. 83
pH:
7
Temp.:
15 °C
Duration:
ca. 714 h
% Recovery:
ca. 45
pH:
9
Temp.:
15 °C
Duration:
ca. 377.1 h
% Recovery:
>= 79 - <= 81
pH:
4
Temp.:
40 °C
Duration:
ca. 719.7 h
% Recovery:
ca. 46
pH:
7
Temp.:
40 °C
Duration:
ca. 377.7 h
% Recovery:
ca. 40
pH:
9
Temp.:
40 °C
Duration:
>= 28.7 - <= 28.8 h
% Recovery:
>= 66 - <= 67
pH:
4
Temp.:
50 °C
Duration:
>= 719.7 - <= 719.8 h
% Recovery:
ca. 32
pH:
7
Temp.:
50 °C
Duration:
232.8 h
% Recovery:
ca. 36
pH:
9
Temp.:
50 °C
Duration:
11.7 d
Key result
pH:
4
Temp.:
25 °C
Hydrolysis rate constant:
0 h-1
DT50:
206 d
Type:
(pseudo-)first order (= half-life)
Remarks on result:
other: Calculated
Remarks:
Extrapolated from results
Key result
pH:
7
Temp.:
25 °C
Hydrolysis rate constant:
0.001 h-1
DT50:
47 d
Type:
(pseudo-)first order (= half-life)
Remarks on result:
other: Calculated
Remarks:
Extrapolated from results
Key result
pH:
9
Temp.:
25 °C
Hydrolysis rate constant:
0.007 h-1
DT50:
4.2 d
Type:
(pseudo-)first order (= half-life)
Remarks on result:
other: Calculated
Remarks:
Extrapolated from results
pH:
4
Temp.:
15 °C
Type:
(pseudo-)first order (= half-life)
Remarks on result:
not determinable
Remarks:
Substance was hydrolytically stable at temperature and pH
pH:
7
Temp.:
15 °C
Hydrolysis rate constant:
0 h-1
DT50:
114 d
Type:
(pseudo-)first order (= half-life)
pH:
9
Temp.:
15 °C
Hydrolysis rate constant:
0.002 h-1
DT50:
13 d
Type:
(pseudo-)first order (= half-life)
pH:
4
Temp.:
40 °C
Hydrolysis rate constant:
0 h-1
DT50:
84 d
Type:
(pseudo-)first order (= half-life)
pH:
7
Temp.:
40 °C
Hydrolysis rate constant:
0.002 h-1
DT50:
14 d
Type:
(pseudo-)first order (= half-life)
pH:
9
Temp.:
40 °C
Hydrolysis rate constant:
0.032 h-1
DT50:
0.9 d
Type:
(pseudo-)first order (= half-life)
pH:
4
Temp.:
50 °C
Hydrolysis rate constant:
0.001 h-1
DT50:
47 d
Type:
(pseudo-)first order (= half-life)
pH:
7
Temp.:
50 °C
Hydrolysis rate constant:
0.004 h-1
DT50:
6.6 d
Type:
(pseudo-)first order (= half-life)
pH:
9
Temp.:
50 °C
Hydrolysis rate constant:
0.084 h-1
DT50:
0.3 d
Type:
(pseudo-)first order (= half-life)
Other kinetic parameters:
Single first-order rate constant calculated, values between 10 and 90% hydrolysis of the test substance were used.
Details on results:
See tables in "Any other information on results " below. Li ions were not monitored in this experiment.

Results for Transformation products:

Table 2: Detected rate of F ion

 

 

A

B

C

D

E

 

Temp

(°C)

Sample Description

Peak area of processed sample

μS.min

Peak area of standard solution

μS.min

Measured concentration of F

mg/L

Theoretical value of F

mg/L

Ratio to theoretical value

%

Ratio to theoretical value

%

15

pH4.0-1

0.416

7.320

2.0

17.6

11

12

pH4.0-2

0.456

7.320

2.2

17.6

13

40

pH4.0-1

0.907

7.320

4.5

17.6

26

27

pH4.0-2

0.950

7.320

4.7

17.6

27

50

pH4.0-1

1.305

7.320

6.4

17.6

36

38

pH4.0-2

1.434

7.320

7.1

17.6

40

15

pH7.0-1

0.579

7.320

2.8

17.6

16

17

pH7.0-2

0.659

7.320

3.2

17.6

18

40

pH7.0-1

2.107

7.156

10.6

17.6

60

61

pH7.0-2

2.150

7.156

10.8

17.6

61

50

pH7.0-1

2.749

7.302

13.6

17.6

77

76

pH7.0-2

2.663

7.302

13.1

17.6

74

15

pH9.0-1

2.490

7.156

12.5

17.6

71

69

pH9.0-2

2.320

7.156

11.7

17.6

66

40

pH9.0-1

2.119

7.397

10.3

17.6

59

59

pH9.0-2

2.110

7.397

10.3

17.6

59

50

pH9.0-1

2.330

7.397

11.3

17.6

64

65

pH9.0-2

2.336

7.397

11.4

17.6

65

 

Concentration of standard solution

F

36.0 mg/L

Concentration of the test substance in test solution

G

100 mg/L

Molecular weight of F

H

19.00

Molecular ratio of F

I

1

Molecular weight of the test substance

J

107.91

 

Equations:

C=A÷B×F

D=G×H×I÷J

E=B÷D×100

 

Table 3: Detected rate of PO3F ion

 

 

A

B

C

D

E

 

Temp

(°C)

Sample Description

Peak area of processed sample

μS.min

Peak area of standard solution

μS.min

Measured concentration of PO3F

mg/L

Theoretical value of PO3F

mg/L

Ratio to theoretical value

%

Ratio to theoretical value

%

15

pH4.0-1

0.075

4.123

1.6

90.8

2

2

pH4.0-2

0.089

4.123

1.9

90.8

2

40

pH4.0-1

0.515

4.123

11.2

90.8

12

13

pH4.0-2

0.543

4.123

11.9

90.8

13

50

pH4.0-1

1.161

4.123

25.3

90.8

28

28

pH4.0-2

1.116

4.123

24.4

90.8

27

15

pH7.0-1

*

*

*

*

*

*

pH7.0-2

*

*

*

*

*

40

pH7.0-1

*

*

*

*

*

*

pH7.0-2

*

*

*

*

*

50

pH7.0-1

*

*

*

*

*

*

pH7.0-2

*

*

*

*

*

15

pH9.0-1

2.208

4.275

43.8

90.8

48

50

pH9.0-2

2.221

4.275

46.8

90.8

52

40

pH9.0-1

2.473

4.555

48.9

90.8

54

55

pH9.0-2

2.516

4.555

49.7

90.8

55

50

pH9.0-1

2.795

4.555

55.2

90.8

61

61

pH9.0-2

2.789

4.555

55.1

90.8

61

*: PO3F ion could not be measured due to the influence of buffer solution

Concentration of standard solution

F

90.0 mg/L

Concentration of the test substance in test solution

G

100 mg/L

Molecular weight of PO3F

H

97.97

Molecular ratio of PO3F

I

1

Molecular weight of the test substance

J

107.91

 

Equations:

C=A÷B×F

D=G×H×I÷J

E=B÷D×100

 

Table 3: Detected rate of PO4 ion

 

 

A

B

C

D

E

 

Temp

(°C)

Sample Description

Peak area of processed sample

μS.min

Peak area of standard solution

μS.min

Measured concentration of PO3F

mg/L

Theoretical value of PO3F

mg/L

Ratio to theoretical value

%

Ratio to theoretical value

%

15

pH4.0-1

0.162

4.038

3.5

88.0

4

4

pH4.0-2

0.116

4.038

2.5

88.0

3

40

pH4.0-1

0.105

4.038

2.3

88.0

3

3

pH4.0-2

0.112

4.038

2.4

88.0

3

50

pH4.0-1

0.061

4.038

1.3

88.0

1

2

pH4.0-2

0.096

4.038

2.1

88.0

2

15

pH7.0-1

*

*

*

*

*

*

pH7.0-2

*

*

*

*

*

40

pH7.0-1

*

*

*

*

*

*

pH7.0-2

*

*

*

*

*

50

pH7.0-1

*

*

*

*

*

*

pH7.0-2

*

*

*

*

*

15

pH9.0-1

0.120

3.803

2.8

88.0

3

3

pH9.0-2

0.071

3.803

1.6

88.0

2

40

pH9.0-1

<0.02

4.044

<0.5

88.0

<1

<1

pH9.0-2

<0.02

4.044

<0.5

88.0

<1

50

pH9.0-1

<0.02

4.044

<0.5

88.0

<1

<1

pH9.0-2

<0.02

4.044

<0.5

88.0

<1

*: PO4 ion could not be measured due to the influence of buffer solution

Concentration of standard solution

F

88.0

Concentration of the test substance in test solution

G

100 mg/L

Molecular weight of PO4

H

94.97

Molecular ratio of PO4

I

1

Molecular weight of the test substance

J

107.91

 

Equations:

C=A÷B×F

D=G×H×I÷J

E=B÷D×100

Table 4: Mass balance

 

 

A

B

C

D

 

 

Temp

(°C)

Sample Description

Residual rate to 0 hour

%

Ratio to theoretical value

F

%

Ratio to theoretical value

PO3F

%

Ratio to theoretical value

PO4

%

Total

A+B

%

Total

A+B+D

%

15

pH4.0-1

91

11

2

4

102

97

pH4.0-2

95

13

2

3

108

100

40

pH4.0-1

79

26

12

3

105

94

pH4.0-2

81

27

13

3

108

97

50

pH4.0-1

66

36

28

1

102

95

pH4.0-2

67

40

27

2

107

96

15

pH7.0-1

83

16

*

*

99

NA

pH7.0-2

83

18

*

*

101

NA

40

pH7.0-1

46

60

*

*

106

NA

pH7.0-2

46

61

*

*

107

NA

50

pH7.0-1

32

77

*

*

109

NA

pH7.0-2

32

74

*

*

106

NA

15

pH9.0-1

45

71

48

3

116

96

pH9.0-2

45

66

52

2

111

99

40

pH9.0-1

40

59

54

<1

99

94

pH9.0-2

40

59

55

<1

99

95

50

pH9.0-1

36

64

61

<1

100

97

pH9.0-2

36

65

61

<1

101

97

 

*: PO3F ion and PO4 ion could not be measured due to the influence of buffer solution

 

 

Validity criteria fulfilled:
yes
Conclusions:
The test substance is considered hydrolytically unstable at pH 4.0, 7.0 and 9.0 under the conditions of the test. The test substance hydrolyses more readily in alkaline conditions than under acidic conditions.

Description of key information

In an OECD guideline study, the test substance is considered hydrolytically unstable at pH 4.0, 7.0 and 9.0 under the conditions of the test. Hydrolysis half-lifes were calculated for the test substance at an environmentally relevant temperature (25°C) at pH 4.0, 7.0 and 9.0.  The test substance hydrolyses more readily in alkaline conditions than under acidic conditions. The half-life value used for the chemical safety assessment was pH 7.0 at 25°C.

Key value for chemical safety assessment

Half-life for hydrolysis:
47 d
at the temperature of:
25 °C

Additional information