1-[difluoro(trifluoromethoxy)methoxy]-1,2,2-trifluoroethylene

Water solubility

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

December 2019 to March 2020

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

not GLP

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Version / remarks:

1995

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Version / remarks:

2008

Deviations:

no

GLP compliance:

no

Type of method:

flask method

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch number of test material: Solvay Manufacture Plant / Batch number: 190530v10
- Expiration date of the lot/batch: May 2023
- Purity test date: 12 December 2019

Key result

Water solubility:

< 5.3 mg/L

Conc. based on:

test mat.

Loading of aqueous phase:

5.2 g/L

Temp.:

30 °C

pH:

6.6

Remarks on result:

not determinable

Remarks:

The reported result is based on 3 measurements, where samples differed for stirring time: 24-48-72 hours. MOVE3 quantity was always below the limit of quantification.

The quantification of MOVE3 concentration is performed using a mass ratio of water to MOVE3.

The MOVE3 peak was not visible on the chromatograms corresponding to the aqueous phase injections even in injecting large sample volume, the MOVE3 quantity was always below the limit of mass quantification: 0.0000194 mg.

The solubility of MOVE3 in water is then considered to be lower than the ratio of the limit of mass quantification divided by the water mass amount quantified by gas chromatography. (The mass of quantified water varies with the uncertainty of measurement and injected volume, which explains the differences in concentrations observed when the ratio is calculated)

The results of the three samples (24, 48, 72h stirring) are given in Table below:

Sample (stirring time)	water mass (mg)	MOVE3 mass (mg)	Solubility (mg/L)	Average (mg/L)
24h	3,4929873	< 0,0000194	< 5,55	< 5,41
	3,6668627	< 0,0000194	< 5,29
	3,6022593	< 0,0000194	< 5,39
48h	3,6703697	< 0,0000194	< 5,29	< 5,14
	3,8511576	< 0,0000194	< 5,04
	3,8010254	< 0,0000194	< 5,10
72h	3,6688931	< 0,0000194	< 5,29	< 5,36
	3,6326321	< 0,0000194	< 5,34
	3,5603502	< 0,0000194	< 5,45

The water solubility is based on the values obtained with the nine values of solubility. The solubility of test item is lower than 0.0053 grams per liter.

Conclusions:

The water solubility of MOVE3 was determined to be < 5.3 mg/L.

Executive summary:

The determination of the water solubility was performed according to the regulation (CE) n°440/2008, A.6: “Water solubility”, May 2008 and to the OECD Guidelines n° 105: “Water solubility”, adopted July, 27, 1995 using the flask method, however, considering the high volatility of the test item, adaptations to the standard procedure were put in place in order to reduce as much as possible losses of the test item from water to the vapour phase during the measurements:

• the samples were loaded into a thermostatically controlled sealed cell equipped with condenser to reflux into the cell the liquid MOVE3 eventually evaporated to the headspace,


• the cell was almost completely filled to the cap in order to limit as much as possible the headspace volume and the potential vaporisation,


• sampling was done by the use of a needle through the cell septum.

 

According to the requirement of OECD TG No 105 and A.6 method the measurement were performed for three different stirring times: 24, 48 and 72hours. The measurement were performed three times with a new filling of the cell for each test. During the test, because of the MOVE3 density higher than the one of water, MOVE3 tended to distributed to the bottom of the cell resulting in an advantage in term of limiting the losses from water to the vapour phase.

 

After the stirring period, the cell was set up at 20 °C and the solutions were maintained at this temperature for 24 hours. In this phase the cell was held with clamps in a stable position that prevents any shaking or vibration to ensure a good settling. For solubility measurements, the aqueous phase was sampled. As MOVE3 is denser than water, during the sampling of the top aqueous phase through the septum, there was no risk of polluting the sampling needle with MOVE3 and thus overestimating the amount of MOVE3 in the water.

 

For all the three samples, MOVE3 quantity was below the limit of quantification.

The water solubility of MOVE3 was calculated to be < 5.3 mg/L.

Reference 2

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 23 December 2015 to July 2017

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

The study was conducted according to recognized standard, however due to the test item properties it was not possible to fulfill the variability criteria defined in the guideline (variability < 15%) for the test item concentration in the different replicates.

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Version / remarks:

July 1995

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Version / remarks:

March 2014

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 830.7840 (Water Solubility)

Version / remarks:

March 1998

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

other: slow stirring flask method

Key result

Water solubility:

6.2 mg/L

Incubation duration:

24 h

Temp.:

20 °C

pH:

8.6

Key result

Water solubility:

2.4 mg/L

Incubation duration:

48 h

Temp.:

20 °C

pH:

8.4

Key result

Water solubility:

3.7 mg/L

Incubation duration:

72 h

Temp.:

20 °C

pH:

8.5

Details on results:

The content of test item dissolved in water during the preliminary test was 6.1 mg/l.

As a result of the extremely high volatility of the test item, the difference between the concentrations determined in the 24, 48 and 72 hour test samples was >15%. Based on this, the water solubility of the test item is given as a range between the lowest and highest result i.e. between 2.4 and 6.2 mg/L.

A small response at the retention time of the test item was detected in the chromatogram of the blank water mixture. Contribution to the other samples based on peak area was maximum 0.2% and therefore considered negligible.

The difference between the concentrations determined in the 24, 48 and 72 hour test samples was>15%.

Based on this, the water solubility of the test item is estimated as a range between the lowest and highest result i.e. between 2.4 and 6.2 mg/L.

All the measures feasible at the lab have been tried in order to reduce the variability on the measurement (i.e. use GC vials intended for headspace analysis as test vessel, fill them completely with water to avoid headspace, close them before adding test item, add cold test item with a cold needle through the septum, stir at reduced speed (100 rpm), take a sample through the septum to avoid any evaporation using a cold needle to avoid loss and transfer the sample through the septum into a closed vial for analysis).

The best that has been obtained is what is described in this report. Since all feasible measures have been implemented, at the current state of laboratory capability a more accurate value for water solubility could not be established for MOVE3.

Conclusions:

The water solubility of the test item at 20°C was between 2.4 and 6.2 mg/l

Executive summary:

The water solubility of the test item was determined with the shake flask method according to recognised guidelines (EU A.6, OECD 105 and OPPTS 830.7840) and under GLP.

The slow-stirring flask method was applied for the determination of the water solubility of MOVE3.

As a result of the extremely high volatility of the test item, the difference between the concentrations determined in the 24, 48 and 72 hour test samples was >15%. Based on this, the water solubility of the test item is given as a range between the lowest and highest result i.e. between 2.4 and 6.2 mg/L.

The pH of the aqueous samples was 8.4 – 8.6.

Description of key information

Two water solubility studies, both conducted according to recognized guidelines, are available.

Both the studies have some limitations which prevents to derive a exact water solubility value, however, the results are consistent and support a water solubility value in the range of 2.4-6.2 mg/L.

For risk assessment purpose the water solubility value of MOVE3 at 20°C is set equal to the average value of the range: 4.3 mg/L.

Key value for chemical safety assessment

Water solubility:

4.3 mg/L

at the temperature of:

20 °C

Additional information

Two water solubility studies are available.

 

In the first study, identified as Key reference, the water solubility of the test item was determined with the shake flask method according to recognized guidelines (EU A.6, OECD 105 and OPPTS 830.7840) and under GLP.

In this study no punctual value of water solubility was determined because of the high variability in MOVE 3 concentration observed between samples. The difference between the concentrations determined in the 24, 48 and 72 hour test samples at 20°C was in fact >15%. Such high variability was ascribed to the extremely high volatility of the test item, affecting reproducibility during handling and sampling. The water solubility of MOVE 3 was therefore estimated as a range between the lowest and highest result i.e. between 2.4 and 6.2 mg/L.

 

In the second study, identified as Supporting reference, the water solubility of the test item was also determined with the shake flask method according to recognized guidelines (EU A.6, OECD 105) but special measures were putted in place for reducing losses for volatilization:

• the samples were loading into thermostatically controlled sealed cells equipped with a condenser to reflux into the cells the liquid MOVE3 eventually evaporated to the headspace,


•  the cells were almost completely filled to the cap in order to limit as much as possible the headspace volume and the potential vaporisation,


• sampling was done by the use of a needle through the cell septum.

However, at the end of the test, the amount of MOVE3 in all the three samples was found below the limit of quantification (i.e. < 5.3 mg/L).

The results of the second study seem to support a slightly lower water solubility for MOVE3 in comparison to the value estimated by the previous study but, considering the lower level of estimated range (i.e. 2.4 mg/L) , it can be concluded that the results are consistent.

For risk assessment purpose the water solubility value of MOVE3 at 20°C is set equal to the average value of the range: 4.3 mg/L.