Reaction mass of N-(2-hydroxypropyl)decan-1-amide and N-(2-hydroxypropyl)octanamide

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

From April 03, 2017 to May 04, 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

no

GLP compliance:

not specified

Type of method:

flask method

Key result

Water solubility:

3.877 g/L

Conc. based on:

test mat.

Loading of aqueous phase:

100 g/L

Incubation duration:

72 h

Temp.:

20 °C

pH:

> 10.32 - < 10.34

Remarks on result:

other: 3.877 ± 0.124

Details on results:

Water solubility measured at different time points:
24 h: 3.945 g/L
48 h: 3.952 g/L
72 h: 3.733 g/L

The pH value of the sample solution was 10.32 (10.32, 10.34) after 24 (48, 72) hours of incubation. The water solubility was determined at 20 °C and an accumulation of the polar components in the test mixture was observed.

Conclusions:

Under the study conditions, water solubility of the test substance was determined to be 3.877 ± 0.124 g/L at 20°C.

Executive summary:

A study was conducted to determine the solubility of the test substance in water according to EU Method A.6. A preliminary tests indicated water solubility above 0.01 g/L, therefore the flask method was used. In the main study about 2 g of the test substance were suspended in 20 mL deionised water and stirred in a heated water bath at 30°C for 24 h, 48 h, and 72 h, respectively. After incubation, the sample suspensions were cooled to 20 °C and kept at this temperature for 24 h without stirring. Afterwards the cloudy solutions were centrifuged (30°C, 3500 rpm, 20 min) and filtrated. 2.0 mL of the slightly cloudy solutions were transferred into 50 mL volumetric flasks and filled up to the mark with methanol. These solutions were analysed by the liquid chromatography. The pH value of the sample solution was 10.32 (10.32, 10.34) after 24 (48, 72) hours of incubation. The water solubility was determined at 20 °C and an accumulation of the polar components in the test mixture was observed. Under the study conditions, the water solubility of the test substance was determined to be 3.877 ± 0.124 g/L at 20°C (Schwarzkopf, 2017).

Description of key information

Water solubility was determined according to OECD Guideline 105 (Schöneck, 2022).

Water solubility was also estimated previously according to EU Method A.6 (Schwarzkopf, 2017)

Key value for chemical safety assessment

Water solubility:

6 687 mg/L

at the temperature of:

20 °C

Additional information

A study was conducted to determine the water solubility of amides, C8-10 (even-numbered), N-(2-hydroxypropyl) in water according to OECD Guideline 105 (shake-flask method). Vessels containing water and the test substance were shaken for approximately 24 hours, 48 hours, and 72 hours, respectively, at about 30°C. Afterwards, the samples were equilibrated for another 24 hours at 20°C. Then, the samples were filtered and diluted, and the concentrations were determined by HPLC with UV-detection. The test substance gave a chromatographic profile consisting of four peaks. Therefore, the test was carried out at two different loading rates. For the loading rate of about 16 g/L, the "water solubility" at 20°C was found to be 4768 mg/L ± 180 mg/L (mean ± standard deviation) for the whole test substance. For the loading rate of about 75 g/L, the "water solubility" at 20°C was found to be 6687 mg/L ± 81 mg/L (mean ± standard deviation) for the whole test substance. From the chromatograms, it was apparent that the profile of the standard solution was significantly different from the chromatogram of a water solubility sample. The peaks of early eluting compounds were present in higher amounts in the sample. These early eluting compounds had a higher polarity and thus a higher water solubility than later eluting compounds. Therefore, these compounds were contributing the most to the water solubility of the test substance.

In an earlier study conducted according to EU Method A.6, the water solubility of the test substance was determined to be 3877 ± 124 mg/L at 20°C.

The value of 6687 mg/L at 20°C at the loading rate of 75 g/L from the OECD Guideline 105 study was retained for risk assessment purposes.