Acetic acid, 2,2-difluoro-2-[[2,2,4,5-tetrafluoro-5-(trifluoromethoxy)-1,3-dioxolan-4-yl]oxy]-, ammonium salt (1:1)

Additional physico-chemical information

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

other: critical micelle concentration

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

November 2020 to July 2022

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

CMC could not be determined in this study, the value was just estimated.

Qualifier:

according to guideline

Guideline:

other: ISO Guide 4311. Anionic and non-ionic surface active agents – Determination of the critical micellization concentration – Method by measuring surface tension with a plate, stirrup or ring.

Version / remarks:

1979

Deviations:

not specified

Qualifier:

according to guideline

Guideline:

other: ASTM D1331. Standard Test Methods for Surface and Interfacial Tension of Solutions of Paints, Solvents, Solutions of Surface-Active Agents, and Related Materials.

Version / remarks:

2014

Deviations:

not specified

Qualifier:

according to guideline

Guideline:

other: OECD Guideline 115. Surface Tension of Aqueous Solutions

Version / remarks:

1995

Deviations:

yes

Remarks:

The guideline is intended for the measurement of the surface tension of a solution at the concentration equal to the 90% saturation mobility. The guideline was used as basis for the determination fo the CMC.

Qualifier:

according to guideline

Guideline:

other: EC Guideline A.5. Surface Tension.

Version / remarks:

2008

Deviations:

yes

Remarks:

The guideline is intended for the measurement of the surface tension of a solution at the concentration equal to the 90% saturation mobility. The guideline was used as basis for the determination fo the CMC.

GLP compliance:

yes

Specific details on test material used for the study:

Three test item were used in the study:

Test item 1 (first main study): 39% cC6O4 aqueous solution
Test item 2 (second main study): cC6O4 dry salt
Test item 3 (third main study): 66.5% cC6O4 aqueous solution

Results:

Main test performed on Test item 3 (i.e.66.5% aqueous solution):

The plot of the surface tension of the test solutions as function of log C is shown in the attached Figure 1. Due to the results not showing a flattening of the curve, no acceptable trendline y2 could be obtained for concentrations below 665.00 g/L. No higher concentrations were tested as 665.00 g/L was the concentration of the undiluted test material (i.e. test item 3).
However, although CMC could not be determined, this value was estimated based on the intersection of the trend lines y1 and y2. Trend line y1 was based on the first three data points which show strong linearity and trend line y2 on the others to have an average on the slight slope.
The curve in the attached Figure 1 did show an inflection point around the 55.4 g/L which was determined based on the intersection of trend lines y1 (y= -27.815x+153.11) and unacceptable y2 (y= 21.179).

Conclusions:

Although no flattening of the curve was observed, a possible CMC effect could be observed around the inflection point of 55.4 g/L. This can however, not be claimed as the CMC value based on the obtained results. Therefore an accurate value of the CMC could not be determined.

Executive summary:

The objective of the study was to determine the critical micelle concentration (CMC) of Cyclic C6O4 ammonium salt in pure water. The test was conducted in GLP according to recognized guidelines. Three different test items were used in the study:

Test item 1 (first main study): 39% cC6O4 aqueous solution 

Test item 2 (second main study): cC6O4 dry salt

Test item 3 (third main study): 66.5% cC6O4 aqueous solution 

 

Multiple main studies were conducted using either the Test item 1 (i.e. 39% cC6O4 aqueous solution), the Test item 2 (i.e. cC6O4 dry salt) or the Test item 3 (i.e. 66.5% cC6O4 aqueous solution) to prepare the different concentrations. None of the studies did result in a reliable result due to absence of stabilization of the surface tension above a certain concentration. In addition, the results of the measurements performed on the cC6O4 dry salt solution were not reliable due to the presence of impurities.

However, although no flattening of the curve was observed, a possible CMC effect could be estimated from the third main study performed on the 66.5% cC6O4 aqueous solution. In fact the curve show an inflection point around the 55.4 g/L which was determined based on the intersection of trend lines y1 (y= -27.815x+153.11) and unacceptable y2 (y= 21.179). This can however, not be claimed as the CMC value based on the obtained results. Therefore, an accurate value of the CMC could not be determined in this study.

Reference 2

Endpoint:

other:

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Remarks:

because of a labelling error of the mother solution, listed as 66% w/w instead of 66,5% w/w, all the calculations for the other concentrations are affected by this kind of bias. It is estimated that the final CMC value is not significantly impacted.

Principles of method if other than guideline:

CMC here was determined measuring both surface tension and conductivity of a surfactant concentration series.
The surface tension of the test material was determined using the tensiometer Kruss GmbH Hamburg K10 with platinum-iridium ring.
The concuctivity data come from Metrohm 912 conductimeter.

GLP compliance:

no

Results:

The CMC values determined with the two techniques on the first set of sample solutions were:
CMC surface tension = 41978 mg/L
CMC conductivity = 30577 mg/L

The CMC values determined with the two techniques on the second set of sample solutions were:
CMC surface tension = 39802 mg/L
CMC conductivity = 36363 mg/L

Looking at the data of the first determination, CMC value determined by surface tension is not so aligned to the conductivity one, in fact, it changes from 41978 to 30577 mg/L respectively. This could be caused by some kind of impurities and contaminants that could affect both surface tension and conductivity of the surface-active species in different ways.
In fact, those solutions were prepared in an external laboratory, analyzed and then shipped for cross check measurements, so being manipulated a lot of times.
The data of the second determination of CMC are obtained from the analysis of fresh solutions prepared in order to evaluate the influence of the possible contamination.
CMC values coming from surface tension measurements and conductivity ones are significantly more comparable between them, in fact they are 39802 mg/L and 36363 mg/L respectively.
This might lead us to think that there was contamination on the first set of sample solutions, but it is also a confirmation of the general trend of the curves and the range of concentration in which we find the CMC value.
Giving the second determination more reliability than the first one, we can conclude that CMC of cC6O4 water solution in between 36363 and 39802 mg/L.

It has to be underlined that because of a labelling error of the mother solution, listed as 66% w/w instead of 66,5% w/w, all the calculations are affected by this kind of bias. However, it is estimated that the final CMC value is not significantly impacted therefore the results are considered reliable.

The graphical data representation of the determinations on the first set of samples is reported in the attached Figure 1 and Figure 2.
The graphical data representation of the determinations on the second set of samples is reported in the attached Figure 3 and Figure 4.
Figure 5 and Figure 6 show the comparison of data between the two determinations.

Conclusions:

The CMC of cC6O4 water solution in between 36 and 40 g/L.

Executive summary:

The CMC of cC6O4 was determined with two techniques (surface tension and conductivity) on two series of sample solutions, prepared starting from the same test item (i.e. 66.5% w/w cC6O4 aqueous solution).

The surface tension of the test material was determined using the tensiometer Kruss GmbH Hamburg K10 with platinum-iridium ring. The concuctivity data come from Metrohm 912 conductimeter.

Looking at the data of the first determination, CMC value determined by surface tension is not so aligned to the conductivity one, in fact, it changes from 41978 to 30577 mg/L respectively. This was ascribed to the presence of impurities and contaminants that could affect both surface tension and conductivity of the surface-active species in different ways. In fact, those solutions were prepared in an external laboratory, analyzed and then shipped for cross check measurements, so being manipulated a lot of times.
The data of the second determination of CMC are obtained from the analysis of fresh solutions prepared in order to evaluate the influence of the possible contamination.
CMC values coming from surface tension measurements and conductivity ones are significantly more comparable between them, in fact they are 39802 mg/L and 36363 mg/L respectively.
This might lead us to think that there was contamination on the first set of sample solutions, but it is also a confirmation of the general trend of the curves and the range of concentration in which we find the CMC value.
Giving the second determination more reliability than the first one, we can conclude that CMC of cC6O4 water solution in between 36363 and 39802 mg/L.

It should also be noted that because of a labelling error of the mother solution, listed as 66% w/w instead of 66,5% w/w, all the calculations are affected by this bias. However, it is estimated that the final CMC value is not significantly impacted therefore the estimated CMC range is considered reliable.

Description of key information

Two CMC studies were performed.

In the first one, conducted via surface tension measurement, no CMC exact value could be determined because no flattening of the curve was observed. The value was however estimated to be approximately 55.4 g/L based on the inflection point of the curve.

In the second study, CMC was determined with both surface tension and conductivity. CMC values coming from the two techniques were comparable. The study concluded that CMC of cC6O4 is between 36 and 40 g/L.

The difference between the results of the two studies can be explained by the different way the curves are built. In spite of this the results of both the studies were in the same order of magnitude and are considered consistent. In conclusion the CMC of cC6O4 is between 36 and 56 g/L.