Bis(acetato-O)hydroxyaluminium

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from 2015-05-12 to 2015-12-07

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

flask method

Specific details on test material used for the study:

Test item: Aluminiumhydroxidacetat-Hydrat
Batch No.: F1859171
CAS No.: 80164-67-6
Molecular formular: C4H7AIO5*H2O
Molecular mass: 180.09 g/mol
Physical state: White solid
Purity: 30.1 % (complexometric, Al2O3)
Storage conditions: Ambient temperature (10 - 30 °C)
Expiry date: 2019-09-30

Key result

Water solubility:

13 mg/L

Conc. based on:

test mat.

Loading of aqueous phase:

0.1 g/L

Incubation duration:

>= 24 - <= 72 h

Temp.:

20 °C

pH:

4.7

Key result

Water solubility:

140 mg/L

Conc. based on:

test mat.

Loading of aqueous phase:

1 g/L

Incubation duration:

>= 24 - <= 72 h

Temp.:

20 °C

pH:

>= 4.6 - <= 4.7

Preliminary visual estimation of the water solubility:

Three preliminary tests were carried out with specified amounts of the test item and 100 mL and 500 mL distilled water, respectively. After each addition of an amount of water, the mixture was stirred for at least 24 hours, and visually checked for any undissolved particles.

Table 1: Results of the preliminary visual estimation of the water solubility

Amount of test item / mg	Total volume / mL	Appearance of mixture
8.9	100	undissolved
8.3	500	undissolved
1.9	500	undissolved

The preliminary visual experiments showed that the water solubility of the test item is < 10 mg/L. In this range the water solubility of organic test items should be determined with the column elution method. The present test item has a purity of 30.1 % (complexometric, Al₂O₃). According to ECHA guidance R.7a the suitable method for such a complex test items is the flask method.

 

Flask method

A main test with two loading rates (0.1 g/L and 1 g/L) was performed. After the equilibration time precipitate was observed in the flasks of the experiments excluding in the blank experiment.

Table 2: Water solubility experiments, loading rate: 0.1 g/L

Experiment	24 h experiment	48 h experiment	72 h experiment	Blank experiment (72 h)
Amount of test item / g	10.9	11.7	10.1	-
Amount of demineralized water / mL	100	100	100	100
Stirring time at 30 °C / h	24	48	72	72
pH at 23 °C	4.7	4.7	4.7	5.8
Measured aluminium concentration / g/L	13	15	12	< 1

 

Mean aluminium concentration of the experiments with a loading rate of 0.1 g/L: 13 mg/L

Table 3: Water solubility experiments, loading rate: 1 g/L

Experiment	24 h experiment	48 h experiment	72 h experiment
Amount of test item / g	102.1	104.8	105.7
Amount of demineralized water / mL	100	100	100
Stirring time at 30 °C / h	24	48	72
pH at 23 °C	4.7	4.6	4.6
Measured aluminium concentration / g/L	140	140	140

 

Mean aluminium concentration of the experiments with a loading rate of 0.1 g/L: 140 mg/L

The results of the water solubility experiments at two different loading rates with the test item demonstrated that the initial weight had an influence on the water solubility of the test item.

Conclusions:

The results obtained at two different loading rates of test item demonstrated that the initial weight of the test item had an influence on the water solubility of the test item. The mean aluminium concentration in the water extracts at a temperature of 20 °C with a loading rate of approx. 0.1 g/L was determined to be 13 mg/L and with a loading rate of approx. 1 g/L at 20 °C was determined to be 140 mg/L, respectively.

Executive summary:

The water solubility was determined according to OECD TG 105 and Regulation (EC) No 440/2008 Part A.6 using the shake flask method with ICP-OES analysis. About 10 g test substance was weighed into 100 mL stoppered Erlenmeyer flasks (nine parallels) according to the estimated solubility based on the Preliminary Test. After the addition of 100 mL demineralized water, the flasks were agitated at 30 °C. The loading rate of this test series was 0.1 g/L. After one day, three of the vessels were removed and re-equilibrated at 20 °C for 24 hours. The content of the vessel was then centrifuged for 30 minutes with 15000 rpm at 20 °C and the concentration in the clear aqueous phase was determined by ICP-OES. The other flasks were treated similarly after initial equilibration at 30 °C for two and three days, respectively. A second test series with loading rate of 1 g/L with 100 g test substance and 100 mL demineralized water was performed under the same conditions. The pH of each sample was recorded. The water solubility of the test substance was determined to be 13 mg/L at loading rate 0.1 g/L and 140 mg/L at loading rate 1 g/L, both at 20 °C ± 1 °C (pH 4.7).

Description of key information

The results obtained at two different loading rates of test item demonstrated that the initial weight of the test item had an influence on the water solubility of the test item. The mean aluminium concentration in the water extracts at a temperature of 20 °C with a loading rate of approx. 0.1 g/L was determined to be 13 mg/L and with a loading rate of approx. 1 g/L at 20 °C was determined to be 140 mg/L, respectively.

Key value for chemical safety assessment

Water solubility:

13 mg/L

at the temperature of:

20 °C

Additional information

The water solubility was determined according to OECD TG 105 and Regulation (EC) No 440/2008 Part A.6 using the shake flask method with ICP-OES analysis (reference 4.8-1). About 10 g test substance was weighed into 100 mL stoppered Erlenmeyer flasks (nine parallels) according to the estimated solubility based on the Preliminary Test. After the addition of 100 mL demineralized water, the flasks were agitated at 30 °C. The loading rate of this test series was 0.1 g/L. After one day, three of the vessels were removed and re-equilibrated at 20 °C for 24 hours. The content of the vessel was then centrifuged for 30 minutes with 15000 rpm at 20 °C and the concentration in the clear aqueous phase was determined by ICP-OES. The other flasks were treated similarly after initial equilibration at 30 °C for two and three days, respectively. A second test series with loading rate of 1 g/L with 100 g test substance and 100 mL demineralized water was performed under the same conditions. The pH of each sample was recorded. The water solubility of the test substance was determined to be 13 mg/L at loading rate 0.1 g/L and 140 mg/L at loading rate 1 g/L, both at 20 °C ± 1 °C (pH 4.7).