Alkali metal tetrakis (perfluoro-alcoholato)metallate

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

July 2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Version / remarks:

27.7.1995

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

flask method

Specific details on test material used for the study:

Name: LiAl(pftb)4
CAS no.: 274933-96-9
Molecular formula: C16F36LiAlO4
Molecular weight: 974.03 g/mol
Appearance: white powder

Water solubility:

47.95 g/L

Conc. based on:

test mat.

Loading of aqueous phase:

400 g/L

Incubation duration:

3 d

Temp.:

20 °C

pH:

6.34

Details on results:

The solubility of AM(pfa)4 in water was determined from the measured concentrations of Alkali in the filtrated and diluted test solutions. The concentration of the test item was calculated from the measured Alkali concentrations and Alkali content in the test item (0.71 %).
As a Tyndall effect was present in the double filtrated solutions (0.45 µm and 0.2 µm PTFE), each filtrate was additionally ultrafiltrated with 3kDa filters via centrifugation at 4500 rpm for 1 hour. None of the 3fold filtrated test solutions showed a Tyndall effect (i.e. a laser beam was not scattered when transmitted through the liquid).
All replicates showed good correspondence. After the analysis of the sample of day 3, the plateau was considered as reached. The water solubility of the test item was stated as 47.95 ±3.25 g/L with a relative standard deviation of 6.8 %.
A difference between 80 g/L solubility of the test item in water determined in the pre-test during the method validation study and 47.95 g/L determined during this study is a result of a presence of the Tyndall effect after double filtration of the test item solution during the pre-test.

Measurements during Equilibration: All data which were acquired during equilibration time (flasks 1A - C, days 1 – 3) are presented in the following table:

Table 6: Equilibration

Day	Temperature [°C]	pH*	Intensity	Conc. A [mg/L]	Conc. Test Item [g/L]	Difference to previous sample [%]
1	20.0	6	142689	357.1	50.30	-
2	20.0	6	150879	379.1	53.39	+6.1
3	20.0	6	132607	330.1	46.50	-12.9

* measured via pH paper

 

After the analysis of the sample of day 3, the plateau was considered as reached.

Measurements at Plateau: The data which were acquired in the flasks 2 – 4 are presented in the following table:

Table 7: Flasks 2 – 4

Flask #	Temperature [°C]	pH*	Conc. A [mg/L]	Conc. Test Item [g/L]
2	20.0	6.35	329.9	46.47
3	20.0	6.34	317.3	44.69
4	20.0	6.34	329.0	46.34

* measured via pH meter

 

Results: All results are presented in the following table:

Table 8: Measurements used for Calculation of Solubility

Day #	Flask #	Concentration [g/L]	Conc. Mean [g/L]	Standard Deviation [g/L]	RSD* [%]
1	1A	50.30	47.95	3.25	6.8
2	1B	53.39
3	1C	46.50
3	2	46.47
3	3	44.69
3	4	46.34

*RSD = relative standard deviation

 

Mean at the plateau was 47.95 ± 3.25 g/L.

Conclusions:

The water solubility of the test item was stated as 47.95 ±3.25 g/L with a relative standard deviation of 6.8 %.

Executive summary:

The solubility of the test item AM(pfa)4 in water was determined by measurement of the Alkali concentration in the filtrated and diluted test solutions using ICP-OES. The concentration of the test item was calculated from the measured Alkali concentrations and Alkali content in the test item (0.71 %).

The preliminary test which is described in the guideline was performed during the validation of the analytical method study 19110701G926. The solubility range was estimated as 50 – 100 g/L. After analysis of 200 g/L nominal load, the dissolved concentration of the test item in water was 80 g/L. For test items with water solubility above 10 mg/L, the flask method was used.

In the main test, 400 g/L AM(pfa)4 were used to prepare a saturated solution as the water solubility detected in the pre-test was approx. 80 g/L (in the guideline, fivefold saturation is proposed). Six flasks were prepared (1A – 1C and 2 – 4); the flasks 1A – 1C were used during an equilibration time. Four flasks (1C (for the sampling point 72 h) and 2 – 4) were set onto the shaker immediately. After 24 ±2 hours, flask 1B (for the sampling point 48 h) and after 48 ±2 hours, flask 1A (for the sampling point 24 h) were set on the shaker and all flasks were shaken for further 24 ±2 hours at room temperature. Then, flasks 1A – 1C were taken from the shaker, tempered at 20.0 ±0.5 °C, samples were taken, membrane filtered, diluted and analysed via ICP-OES. Due to a difference of less than 15 % in the concentrations on days 2 and 3 and no upward tendency, the test was finished on day 3. The final measurement was performed as determination from flasks 2 – 4.

As a Tyndall effect was present in the double filtrated solutions (0.45 µm and 0.2 µm PTFE), each filtrate was additionally ultrafiltrated with 3kDa filters via centrifugation at 4500 rpm for 1 hour. None of the 3fold filtrated test solutions showed a Tyndall effect (i.e. a laser beam was not scattered when transmitted through the liquid).

 

At the plateau, the concentration of AM(pfa)4 in water had reached 47.95 ±3.25 g/L at 20.0 °C and pH 6.34 – 6.35 = 47.95 ±3.25 kg/m³ (SI units) (mean value ± standard deviation of six individual flasks).

Description of key information

The water solubility of the test item at 20 °C was stated as 47.95 ±3.25 g/L with a relative standard deviation of 6.8 %.

Key value for chemical safety assessment

Water solubility:

47.95 g/L

at the temperature of:

20 °C