Phthalaldehyde

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2018-04-05 to 2018-07-04

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

GLP compliance:

no

Type of method:

flask method

Key result

Water solubility:

37.7 g/L

Conc. based on:

test mat. (dissolved fraction)

Temp.:

20 °C

pH:

ca. 4.6

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 15 minutes and visually checked for any undissolved particles. Table 1 summarizes results of the preliminary test.

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
103.6	0.1	0.1	not dissolved
	0.4	0.5	not dissolved
	0.5	1.0	not dissolved
	1.0	2.0	not dissolved, particles visible
	8.0	10.0	turbid solution, no particles visible
	90.0	100.0	slightly turbid solution

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 determinded by the flask method in the main test.

Flask method

After the equilibration time precipitate was observed in the flasks of the experiments excluding the ones in the blank experiment. The water solubility was calculated from the measured and unrounded concentration values and not from the rounded values given in Table 2.

Table 2: Results of the water solubility experiments with the test item

Experiment	24 h experiment	48 h experiment	72 h experiment	Blank experiment (72 h)
Amount of test item / g	2.54	2.55	2.59	-
Amount of demineralized water / mL	10	10	10	10
Stirring time at 30 °C / h	24	48	72	72
pH at ambient temperature	4.7	4.4	4.5	5.9
Dilution factor	10000	10000	10000	2
Measured concentration / mg/L	3.751 / 3.797	3.655 / 3.664	3.838 / 3.919	- / -
Mean concentration / mg/L	3.774	3.660	3.879	-
Water solubility / g/L	37.7	36.6	38.8	-

The water solubility of the test item at 20 °C was determined to be 37.7 g/L (± 1 g/L); standard deviation derived from the three experiments: 24 h, 48 h and 72 h.

Conclusions:

The water solubility of the test item at 20 °C was 37.7 g/L (± 1 g/L) and the saturated solutions had a pH of ca. 4.6.

Executive summary:

The water solubility of the test item was determined according to EC method A.6. and OECD test guideline 105 using the flask method and HPLC/UV as analytical method. The water solubility of the test item was found to be 37.7 g/L (± 1 g/L) at 20 °C and the saturated solutions had a pH of ca. 4.6.

Description of key information

The water solubility of the test item was found to be 37.7 g/L (± 1 g/L) at 20 °C and the saturated solutions had a pH of ca. 4.6.

Key value for chemical safety assessment

Water solubility:

37.7 g/L

at the temperature of:

20 °C

Additional information

The water solubility of the test item was determined according to EC method A.6. and OECD test guideline 105 using the flask method and HPLC/UV as analytical method.