Reaction mass of methyl 2-methylbenzene-1-sulfonate and methyl toluene-4-sulphonate

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

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:

yes (incl. QA statement)

Type of method:

flask method

Key result

Water solubility:

0.955 g/L

Conc. based on:

test mat.

Loading of aqueous phase:

5 g/L

Temp.:

20 °C

pH:

1.7

Remarks on result:

other: Mean value of two determinations (Flask B and Flask C)

Details on results:

By end of the test it was visually observed that in Flask A no undissolved parts of the test item were present anymore whereas in the test solutions of Flask B and Flask C undissolved droplets were still visible. It was therefore assumed that the test item might not be completely stable in aqueous media after 96 hours stirring time (72 h at 30 °C and 24 h at 20 °C).

The beginning hydrolytic degradation of the test item was indicated as the chromatograms of the aqueous test solutions show an additional peak at approx. 1.3 min – most likely the hydrolysis product of the test item.

Conclusions:

The water solubility of test substance in demineralized water at 20 °C was 0.955 g/L measured at approx. pH 1.7.

Executive summary:

The water solubility is determined based on the methods described in the OECD Guideline 105 and EC Guideline A.6. In a preliminary test, the water solubility of the test substance was found to be higher than 0.01 g/L. Therefore the flask method was chosen for the determination of the water solubility. For the main test, a quantity of the test item necessary for saturation is dissolved in demineralized water. The vessels are stoppered and stirred on a magnetic stirrer for 24 h, 48 h and 72 h at 30 °C in a temperature controlled water bath. Following this procedure, the temperature is reduced to 20 °C and the vessels are kept in the temperature controlled water bath for another 24 h. After phase separation by filtration with a disposable syringe filter and/or centrifugation, respectively, the concentration of the test substance in the aqueous test solutions is determined by HPLC-analysis with UV-detection. By end of the test it was visually observed that in Flask A no undissolved parts of the test substance were present anymore whereas in the test solutions of Flask B and Flask C undissolved droplets were still visible. It was therefore assumed that the test substance might not be completely stable in aqueous media after 96 hours stirring time (72 h at 30 °C and 24 h at 20 °C). The beginning hydrolytic degradation of the test item was indicated as the chromatograms of the aqueous test solutions show an additional peak at approx. 1.3 min – most likely the hydrolysis product of the test substance. The deviation between the single determinations (Flask B and Flask C) was lower than 15 %. The validity criteria of OECD Guideline 105 have therefore been met. The water solubility in demineralized water at 20 °C was 0.955 g/L (pH-value approx. 1.7).

Description of key information

The water solubility is determined based on the methods described in the OECD Guideline 105 and EC Guideline A.6 by flask method.

For the main test, a quantity of the test item necessary for saturation is dissolved in demineralized water. The vessels are stoppered and stirred on a magnetic stirrer for 24 h, 48 h and 72 h at 30 °C in a temperature controlled water bath. Following this procedure, the temperature is reduced to 20 °C and the vessels are kept in the temperature controlled water bath for another 24 h.

The water solubility of test substance in demineralized water at 20 °C was determined as 0.955 g/L (pH-value approx. 1.7).

Key value for chemical safety assessment

Water solubility:

0.955 g/L

at the temperature of:

20 °C

Additional information

By end of the test it was visually observed that in Flask A no undissolved parts of the test substance were present anymore whereas in the test solutions of Flask B and Flask C undissolved droplets were still visible. It was therefore assumed that the test substance might not be completely stable in aqueous media after 96 hours stirring time (72 h at 30 °C and 24 h at 20 °C).

The beginning hydrolytic degradation of the test item was indicated as the chromatograms of the aqueous test solutions show an additional peak at approx. 1.3 min – most likely the hydrolysis product of the test item.