Allyltrimethylsilane

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

27 Feb to 29 Mar 2019

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)

Remarks:

Department of Health of the Government of the United Kingdom, Medicines and Heathcare products Regulatory Agency (MHRA)

Type of method:

flask method

Water solubility:

0.004 g/L

Temp.:

20 °C

pH:

>= 2.5 - <= 2.8

Remarks on result:

other: This result may be a slight underestimate due to the volatile nature of the test item.

Results

 

Preliminary Test

The preliminary estimates of the water solubility at 20.0 ± 0.5 °C were 2.13 x 10-3 g/L and 1.70 x 10-3 g/L. The solutions had a pH of 4.8 and 4.3 respectively.

 

Definitive Test

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

 

Sample Number	Time Shaken at ~ 30 ºC (hours)	Concentration (g/L)	Corrected Concentration (g/L)	Solution pH
1	24	2.74 x 10-3	4.48 x 10-3	2.8
2	48	2.51 x 10-3	4.10 x 10-3	2.6
3	72	1.75 x 10-3	2.86 x 10-3	2.5

 

Mean corrected concentration: 3.82 x 10-3 g/L at 20.0 ± 0.5 ºC

 

Validation

The linearity of the detector response with respect to concentration was assessed over the nominal concentration range of 1 to 50 mg/L. The results were satisfactory with a correlation coefficient (r) of 0.996 being obtained.

 

Assessment of the sample recovery procedure was performed and proved adequate for the test; at a nominal concentration of 25.1 mg/L, a mean percentage recovery of 61.2% was obtained (range 58.0 to 64.7%). Test sample concentrations have been corrected for the recovery of analysis.

 

Discussion

On completion of the equilibration period, the samples were clear and colorless with excess test item present. The solutions had their surface vacuum skimmed to avoid sampling contamination from any test item floating on the surface. After centrifugation, the removed supernatant was visually observed to be clear, colorless, free from un-dissolved test item and had no definitive Tyndall beam effect.

 

The first preliminary test was performed with a large amount of test item, a minimal headspace, slower shaking speed and shaken directly at 20 °C. The purpose of this, because the test item was known to be volatile, was to minimise volatilisation during the test. The large amount of test item covered the surface of the water and slower shaking speed effectively created a barrier for the dissolved test item from volatising. The small headspace also reduced the amount of test item than could volatilise into this space. The temperature was reduced from the usual 30 °C to 20 °C to again reduce the potential for the test item to volatilise.

 

As the first preliminary test didn’t give a result as high as was expected, several changes were made for the second preliminary test to compare what effect they had. The shaking speed and temperature were raised to 200 rpm and 30 °C respectively to see if these facilitated the test item to dissolve. Although the same loading rate was used, less water was used so that the surface area between the test item and water was larger to give a better chance for the test item to dissolve; in the first preliminary test the minimal headspace had the effect of having a small surface area. Even so, the result for second preliminary test was not significantly different.  The definitive test was performed similar to the second preliminary test as this more closely followed the test guidelines.

Due to the test item having a low boiling point and being volatile, it was suspected it would volatilise from aqueous sample readily. For this reason, changes and precautions were tried with the water solubility test in an attempt to minimize this. However, it cannot be guaranteed that volatilisation of the test item from the aqueous solutions was totally prevented, especially during handling when the solutions were disturbed e.g. extraction shaking and draining from a pipette. These issues might be partly due to the differences in the individual sample results. Therefore, it may be difficult to get replicate results within ± 15% of the mean to satisfying the criteria specified in the guidelines.

 

It was therefore considered that the water solubility result maybe be a slight underestimate of the actual water solubility of the test item. However, due to the test item’s volatility, a solution may have difficulty reaching such a concentration or even maintaining it for a considerable period.

 

Conclusion

The water solubility of the test item has been determined to be 3.82 x 10-3 g/L of solution at 20.0 ± 0.5 °C. This result may be a slight under estimate due to the volatile nature of the test item.

Description of key information

Water solubility: ca. 3.82E-03 g/L at 20 °C, pH 2.5 - 2.8. (OECD 105, flask method).

Key value for chemical safety assessment

Water solubility:

0.004 g/L

at the temperature of:

20 °C

Additional information

This result may be a slight under estimate due to the volatile nature of the test item.