4-hydroxybenzaldehyde

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

07. - 15.12.2017

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:

no

Type of method:

flask method

Key result

Water solubility:

7.77 g/L

Conc. based on:

test mat.

Incubation duration:

>= 24 - <= 72 h

Temp.:

20 °C

pH:

4.7

Preliminary test

In a stepwise procedure, increasing volumes of demineralized water were added at room temperature to a defined amount of the test item. After each addition of an amount of water the mixture was treated with ultrasound for 10 minutes and visually checked for any undissolved particles. An additional test with 102.2 mg test item in 100 mL of water was performed.

Table 1: Results of the preliminary test

Amount of test item / mg	Added volume of demineralized water / mL	Total volume of demineralized water / mL	Appearance of mixture
98.5	0.1	0.1	not dissolved
	0.4	0 5	not dissolved
	0.5	1.0	not dissolved
	1.0	2.0	not dissolved
	8.0	10	not dissolved
102.2	100	100	dissolved

Three additional preliminary tests were carried out with specified amounts of the test item and 100 mL and 500 mL demineralized water, respectively. After each addition of an amount of water, the mixture was stirred for 6 hours, and visually checked for any undissolved particles.

 

Table 2: Results of the preliminary test

Amount of test item / mg	Total volume of demineralized water / mL	Appearance of mixture
9.9	100	dissolved
11.0	500	dissolved
2.8	500	dissolved

The preliminary test showed that the water solubility of the test item is > 10 mg/L. According to the preliminary test the water solubility was determined by the flask method in the main test.

In the main test mixtures with a concentration of approx. 50 g/L test item in demin. water were used.

 

Flask method

After the equilibration time precipitate was observed in the flasks of the experiments excluding in the blank experiment. The water solubility was calculated from the measured and unrounded concentration values and not from the rounded values given in the table below.

 

Table 3: Water solubility experiments of the test item

Experiment	24 h experiment	48 h experiment	72 h experiment	Blank experiment (72 h)
Amount of test item / g	2.51	2.51	2.50	-
Amount of demineralized water / mL	50	50	50	50
Stirring time at 30 °C / h	24	48	72	72
pH at 24 °C	4.7	4.7	4.7	6.0
Dilution factor	10000	10000	10000	10000
Measured concentration / mg/L	0.778 / 0.778	0.773 / 0.775	0.778 / 0.778	-/-
Mean concentration / mg/L	0.778	0.774	0.778	-
Water solubility / g/L	7.78	7.74	7.78	-

The water solubility of the test item at 20 °C was determined to be 7.77 g/L (± 0.03 g/L).

Conclusions:

The water solubility of the test substance was determined to be 7.77 g/L at 20 °C.

Executive summary:

The water solubility of the test item was determined according to OECD 105 and Regulation (EC) No. 440/2008 method A.6 using the shake flask method with HPLC analysis. About 2.5 g of the test item were dissolved in 50 mL demineralized water. the flasks were agitated at 30 °C. 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 at 20 °C and the concentration in the clear aqueous phase was determined by HPLC. The other flasks were treated similarly after initial equilibration at 30 °C for two and three days, respectively. The samples were diluted before the analysis (two parallel dilutions). The concentration of test item was determined by means of HPLC. The pH of each sample was recorded. The water solubility of the test item at a temperature of 20 °C was found to be 7.77 g/L ± 0.03 g/L (pH = 4.7).

Description of key information

The water solubility of the test item was determined to be 7.77 g/L at 20 °C (reference 4.8-1).

Key value for chemical safety assessment

Water solubility:

7.77 g/L

at the temperature of:

20 °C

Additional information

The water solubility of the test item was determined according to OECD 105 and Regulation (EC) No. 440/2008 method A.6 using the shake flask method with HPLC analysis. About 2.5 g of the test item were dissolved in 50 mL demineralized water. the flasks were agitated at 30 °C. 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 at 20 °C and the concentration in the clear aqueous phase was determined by HPLC. The other flasks were treated similarly after initial equilibration at 30 °C for two and three days, respectively. The samples were diluted before the analysis (two parallel dilutions). The concentration of test item was determined by means of HPLC. The pH of each sample was recorded. The water solubility of the test item at a temperature of 20 °C was found to be 7.77 g/L ± 0.03 g/L (pH = 4.7) (reference 4.8-1).