Registration Dossier

Diss Factsheets

Administrative data

Endpoint:
dissociation constant
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
the study does not need to be conducted because the substance is hydrolytically unstable (half-life less than 12 hours)
Cross-reference
Reason / purpose for cross-reference:
data waiving: supporting information
Reference
Endpoint:
hydrolysis
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Adequately documented investigation of hydrolysis rate in contact with water and atmospheric moisture, using non-standard methodology which is however suitable for the particular properties of the test substance.
Principles of method if other than guideline:
[1] Observation of speed of dissolution and hydrolysis in water by measurement of HF formation by pH determination and LiF formation by pF determination.
[2] Observation of reaction with atmospheric moisture by accurate monitoring of sample weight change.
GLP compliance:
not specified
Remarks:
This study was a bespoke test performed by the manufacturer of the substance. This study was not carried out specifically for REACH, however it provides key information to show the substance is hydrolytically unstable and relevant for risk assessment.
Analytical monitoring:
yes
Details on test conditions:
Hydrolysis on contact with water.
Experiment 1:
5g samples of test material added to 500 ml volumes of water with stirring - test run with water at 20, 30, 40, 50 and 60C. pH and pF recorded at start (T0) and when reaction appeared complete, as judged by pH/pF change (15-21 seconds after sample addition).
Experiment2:
different amounts of test substance (5-50g) added to 500 ml volumes of water with stirring, at 20C. pH and pF recorded at start (T0) and when reaction appeared complete, as judged by pH/pF change (21-49 seconds after sample addition).
Experiment 3:
30g samples of test material added to 500 ml volumes of water with stirring - test run with water at 20, 30, 40, 50 and 60C. pH and pF recorded at start (T0) and at intervals until the reaction appeared complete, as judged by pH/pF change (11-42 seconds after sample addition).

Reaction with atmospheric moisture.
Experiment 1:
approximately 1g samples of test material (accurately weighed to 0.1 mg) exposed to high humidity atmospheres (84.4-93.6% RH) for up to 150 minutes, with accurate recording of sample mass at frequent intervals. Separate determinations for two test samples showing some difference in particle size (designated big and small).
Experiment 2:
3 further determinations of sample mass change in moist air of differing RH (54.7-85.8%), over time periods up to 160 minutes and using the test material designated small particle size.
Number of replicates:
Hydrolysis in contact with water: 3 experiments, 5 different test temperatures.
Reaction with atmospheric moisture: 2 experiments, different RH levels and sample particulate sizes.
Statistical methods:
Not applicable
Transformation products:
yes
No.:
#1
No.:
#2
No.:
#3
Details on hydrolysis and appearance of transformation product(s):
It was known that the test substance reacts rapidly with water, releasing HF/hydrofluoric acid, LiF and phosphoric acid. The hydrolysis reaction was followed by measurement of pH and PF.
Reaction with atmospheric moisture was shown to follow a biphasic pattern: an initial increase considered to reflect water absorption was followed by a decrease associated with release of POF3 and HF.


DT50:
< 3 s
Type:
not specified
Remarks on result:
other: hydrolysis rate constant not determined

Reaction with water: Experiment 1

Sample number

Temperature[C]

Sample weight

pH Start

pH End

pF Start

pF End

End time

(secs)

1

20

5.06

6.35

4.32

7.05

4.46

20

2

30

5.03

6.52

4.57

8.51

4.91

15

3

40

5.05

6.02

4.66

7.03

4.84

20

4

50

5.04

5.87

4.65

6.63

4.91

20

5

60

5.02

6.00

4.60

7.20

5.05

21

Reaction with water: Experiment 2

Sample number

Temperature[C]

Sample weight

pH Start

pH End

pF Start

pF End

End time

(secs)

1

20

5

6.00

4.60

7.20

5.05

21

2

20

20

7.45

3.17

7.18

3.18

31

3

20

30

6.23

3.52

7.23

3.71

42

4

20

40

6.43

3.06

7.32

3.31

49

5

20

50

6.25

3.08

7.12

3.48

32

Reaction with water: Experiment 3 (summarised)

Sample number

Temperature[C]

Sample weight

pH Start

pH End

pF Start

pF End

End time

(secs)

1

20

30

6.23

3.52

7.23

3.71

42

2

30

30

6.53

3.32

7.68

3.74

22

3

40

30

5.70

3.53

6.76

3.96

16

4

50

30

5.39

2.70

6.18

3.37

29

5

60

30

5.70

1.75

6.06

3.05

11

Reaction with water: Experiment 3 (full results)

Temperature 20 C sample 30g

Temperature 30 C sample 30g

Temperature 40 C sample 30g

Time (secs)

pH

pF

time

pH

pF

time

pH

pF

0

6.23

7.23

0

6.53

7.68

0

5.70

6.76

3

3.55

3.75

3

3.35

3.77

3

3.56

3.99

5

3.55

3.74

5

3.34

3.76

5

3.55

3.98

10

3.54

3.73

10

3.33

3.75

10

3.54

3.97

20

3.53

3.73

22

3.32

3.74

16

3.53

3.96

30

3.53

3.72

 -

-

-

-

-

-

42

3.52

3.71

 -

-

-

-

-

-

Temperature 50 C sample 30g

Temperature 60 C sample 30g

 

 

 

Time (secs)

pH

pF

time

pH

pF

 

 

 

0

5.39

6.18

0

5.70

6.06

 

 

 

3

2.75

3.40

3

1.77

3.07

 

 

 

5

2.74

3.39

5

1.76

3.06

 

 

 

10

2.73

3.38

11

1.75

3.05

 

 

 

Moist air reaction, Experiment 1: LPF big particle, 19.6 C, humidity 93.6%

Time [min]

Mass [g]

Time [min]

Mass [g]

Time [min]

Mass [g]

0

1.0438

60

1.0502

110

1.0761

10

1.0547

70

1.0540

120

1.0802

20

1.0596

80

1.0583

130

1.0864

30

1.0545

90

1.0641

140

1.0902

40

1.0520

100

1.0699

150

1.0974

50

1.0491

-

-

-

-

Mass increase: (1.0596-1.0438) /1.0438=1.5% time: 20min. Mass decrease: (1.0596-1.0491) /1.0596=0.99% time: 30min.

Moist air reaction, Experiment 1: LPF small particle, 20.7 C, humidity 84.4%

Time [min]

Mass [g]

Time [min]

Mass [g]

Time [min]

Mass [g]

0

1.0049

30

1.0071

60

0.9970

5

1.0095

35

1.0039

65

0.9977

10

1.0133

40

1.0008

70

0.9987

15

1.0137

45

0.9988

75

0.9998

20

1.0125

50

0.9977

80

1.0010

25

1.0097

55

0.9973

85

1.0025

Mass increase: (1.0137-1.0049) /1.0049=0.87% time: 15min. Mass decrease: (1.0137-0.9970) /1.0137=1.65% time: 45min.

Moist air reaction, Experiment 2: LPF small particle, 20.7 C, humidity 85.8%

Time [min]

Mass [g]

Time [min]

Mass [g]

Time [min]

Mass [g]

0

1.0462

25

1.0456

50

1.0468

5

1.0491

30

1.0444

55

1.0482

10

1.0520

35

1.0438

60

1.0497

15

1.0496

40

1.0441

65

1.0511

20

1.0478

45

1.0451

70

1.0524

Mass increase: (1.0520-1.0462) /1.0462=0.55% time: 10min. mass decrease: (1.0520-1.0438) /1.0520=0.78% time: 25min.

Moist air reaction, Experiment 2: LPF small particle, 20.4 C, humidity 65.1%

Time [min]

Mass [g]

Time [min]

Mass [g]

Time [min]

Mass [g]

0

1.0201

35

1.0031

70

0.9991

5

1.0235

40

1.0008

75

1.0002

10

1.0238

45

0.9992

80

1.0008

15

1.0201

50

0.9992

85

1.0010

20

1.0155

55

0.9990

90

1.0028

25

1.0113

60

0.9988

95

1.0037

30

1.0070

65

0.9987

100

1.0047

Mass increase: (1.0238-1.0201) /1.0201=0.36% time: 10min. Mass decrease: (1.0238-0.9987) /1.0238=0.25% time: 55min.

Moist air reaction, Experiment 2: LPF small particle, 21.5 C, humidity 54.7%

Time [min]

Mass [g]

Time [min]

Mass [g]

Time [min]

Mass [g]

0

1.0567

55

1.0194

110

1.0073

5

1.0585

60

1.0177

115

1.0070

10

1.0596

65

1.0159

120

1.0064

15

1.0599

70

1.0143

125

1.0054

20

1.0571

75

1.0119

130

1.0060

25

1.0533

80

1.0110

135

1.0058

30

1.0479

85

1.0114

140

1.0057

35

1.0440

90

1.0101

145

1.0056

40

1.0381

95

1.0097

150

1.0065

45

1.0265

100

1.0092

155

1.0080

50

1.0226

105

1.0074

160

1.0088

Mass decrease: (1.0599-1.0567) /1.0567=0.30% time: 15min. Mass decrease: (1.0599-1.0056) /1.0599=5.12% time: 130min.

Conclusions:
Rapid reaction with water releases HF and LiF, leading to production of dissolved F- ions; subsequently, release of Li+ and PO4(3-) ions will follow.

Data source

Materials and methods

Results and discussion

Applicant's summary and conclusion