Diphenyl methylphosphonate

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2012

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

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

flask method

Water solubility:

1.56 g/L

Temp.:

20 °C

pH:

>= 5.4 - <= 5.5

Remarks on result:

other: Mean value of two determinations

Details on results:

Preliminary test
The preliminary estimate of water solubility was greater than 1.28 g/L at 20 °C.

Definitive test
Mean concentration: 1.56 g/L at 20.0 ± 0.5 °C (Samples 1 and 2)
Range: 1.53 to 1.59 g/L

Validation
The linearity of the detector response with respect to concentration was assessed over the concentration range of 0 to 1.00 x 10^3 mg/L. This was satisfactory with a correlation coefficient (r^2) of 1.000 being obtained.

The concentration (g/L) of test item in the sample solutions is shown in the following table:

Sample number	Time shaken at ~30 °C [h]	Time equilibrated at 20 °C [h]	Concentration [g/L]	Solution pH
1	24	24	1.59	5.5
2	48	24	1.53	5.4
3	72	24	0.923^*	5.2

^*Sample 3 not used in final result.

As the water solubility was determined during the preliminary test to be above 1x10^-2 g/L, the flask shaking test was performed. The preliminary sample had no remaining visible excess test item after the equilibration period. Even so, the sample was analysed to determine if significant hydrolysis had occurred, this was not the case and gave a result of greater than 1.28 g/L. Therefore, it was decided to perform the definitive test at a loading rate of 10 g/L in expectation that the water solubility of the test item would not be significantly greater than 1.28 g/L. The preliminary test also indicated that as significant hydrolysis had not occurred, short term shaking periods for the definitive test were not required.

It is evident from the information obtained in the hydrolysis test (see IUCLID section 5.1.1) and data relating to the pH of the test item in water that negligible hydrolysis of the sample solution occurred during the course of the water solubility test.

The definitive result was calculated using Samples 1 and 2. For an unknown reason, Sample 3 was significantly lower than these and was therefore not included. As the preliminary result also indicated the water solubility was greater than 1.28 g/L, it was considered that not using Sample 3 was justified.

Conclusions:

Interpretation of results: soluble (1000-10000 mg/L)
water solubility = 1.56 g/L at 20.0 ± 0.5 °C

Executive summary:

The water solubility of the test substance has been determined to be 1.56 g/L at 20.0 ± 0.5 °C by using the flask method in a GLP study (2012) according to OECD 105 and EU method A.6.

Description of key information

The water solubility of the test substance has been determined to be 1.56 g/L at 20.0 ± 0.5 °C by using the flask method in a GLP study (2012) according to OECD 105 and EU method A.6.

Key value for chemical safety assessment

Water solubility:

1 560 mg/L

at the temperature of:

20 °C