Monopentaerythritol tetraesters and dipentaerythritol hexaesters of 2-ethylhexanoic and n-valeric acids

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

10 - 21 Aug, 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

GLP compliance:

yes (incl. QA statement)

Remarks:

Landesamt für Umwelt, Wasserwirtschaft und Gewerbeaufsicht, Mainz, Germany

Type of method:

other: Flask method with TOC determination

Water solubility:

1.5 mg/L

Conc. based on:

other: TOC

Loading of aqueous phase:

10 g/L

Temp.:

20 °C

pH:

7.94

Water solubility:

5.1 mg/L

Conc. based on:

other: TOC

Loading of aqueous phase:

100 g/L

Temp.:

20 °C

pH:

7.51

Measurements during Equilibration

The data which was acquired during equilibration time (flask 1A-C, days 1 – 6) is presented in the following table:

Equilibration (flasks 1A – 1C)

Day	Temperature [°C]	pH*	Measured DOC values [mg/L]	Concentration test item [mg/L]	Difference to previous sample [%]
1	19.8	6	2.0	3.0	-
2	19.8	6	2.0	3.1	+3.1
3	19.7	6	2.3	3.4	+12.4
4	20.0	6	3.8	5.8	+67.4
5	19.9	6	2.6	3.9	-32.9
6	19.9	6	2.9	4.4	+13.7

*measured via pH paper

The carbon content of 66 % was used in the calculation of the test item concentration from the measured DOC concentration.

The measured value in the blank flask lay below the LOQ of TOC (< 1.1 mg/L).After the analysis of the sample of day 6, the plateau was considered as reached.

Measurements at Plateau

The following table gives the values which were measured at the plateau.

Plateau (flasks 2 – 6)

Flask	Temperature [°C]	pH*	Measured DOC values [mg/L]	Concentration test item [mg/L]	Nominal Load [g/L]
2	20.0	7.94	1.0	1.5	10.0
3	19.9	7.65	1.4	2.0	20.0
4	20.0	7.48	2.1	3.1	40.0
5	20.0	7.39	2.8	4.2	80.1
6	19.9	7.51	3.4	5.1	100.0

*measured via calibrated pH meter

Results

Measurements used for Calculation of Solubility

Flask	Measured Conc. Test Item [mg/L]	Nominal Conc. Test Item [g/L]	Dissolved Part [%]	pH value
2	1.5	10.0	0.02	7.94
3	2.0	20.0	0.01	7.65
4	3.1	40.0	0.01	7.48
1*	3.9	60.0	0.01	-**
5	4.2	80.1	0.01	7.39
6	5.1	100.0	0.01	7.51

*mean value of flasks 1A – 1C (days 1 – 6)

**value was not measured via pH meter

Dependency of pH value on amount of the test item (nominal load) was not perceived.

As solubility was dependent on nominal concentration, no exact value for the solubility of the test item in water can be stated. The solubility range for the tested nominal concentra-tion 10 – 100 g/L is 1.5 – 5.1 mg/L at 20.0 ± 0.5 °C, corresponding to 0.01 % of the test item relating to the nominal concentration of the test item. No Tyndall effect (i.e. a laser beam was not scattered when transmitted through the liquid) could be observed indicating that no colloidal dispersed particles or micells are present.

As dissolved carbon as sum parameter for dissolved test item was measured, this study cannot distinguish between water solubility and hydrolysis of the test item.

Description of key information

Solubility range 1.5 – 5.1 mg/L is stated for the tested nominal concentration 10 – 100 g/L at 20.0 ± 0.5 °C, pH = 7.5 - 7.9 (OECD 105, via TOC method).