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

Dissociation constant

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

dissociation constant

Type of information:

experimental study

Adequacy of study:

key study

Study period:

November 2021

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 112 (Dissociation Constants in Water)

Deviations:

yes

Remarks:

Temperature was not registered during the measurements.

GLP compliance:

no

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source: Solvay Specialty Polymers S.p.A (Manufacturer)
- Lot/batch number of test material: LW 4670388
- Name as reported on the test report: Labware 5467285

Purity by NMR spectroscopy:
F-Diox Acid > 98% w/w by NMR internal method
Water Content: 0,1 % w/w by Karl Fisher

Expiry Date: September 2023

Dissociating properties:

yes

pKa:

1.16

Remarks on result:

other: at room temperature

 

pKa TEST 1	pKa TEST 2	pKa TEST 3
1.29	1.09	1.14
1.28	1.12	1.15
1.28	1.12	1.14
1.26	1.11	1.14
1.24	1.10	1.15
1.24	1.08	1.14
1.23	1.10	1.13
1.21	1.10	1.12
1.20	1.09	1.12
1.19	1.10	1.12

mean = 1,16

std dv = 0,07

Conclusions:

pKa = 1.16 (dev.st = 0.07).
The substance is a strong acid.

Executive summary:

The determination of the dissociation constant requires a measure of the concentrations of the dissociated and undissociated forms of the chemical substance and their pH dependence.
A test solution was prepared by weighting approximately 0.25 g (0.0001g precision) of test substance then solubilized in 50 ml of bidistillated water.
The test solution was titrated with the standard base solution (NaOH 0.1 N), measuring the pH after each addition of titrant.
The pKa is calculated for 10 measured points on the titration curve across the half-neutralization point (HP1) and before neutralization point (EP1). The test was repeated 3 times on three different replicates.

The measured pKa is 1.16 (dev.st = 0.07).

Reference 2

Endpoint:

dissociation constant

Type of information:

experimental study

Adequacy of study:

key study

Study period:

November 2021

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 112 (Dissociation Constants in Water)

Deviations:

yes

Remarks:

Temperature was not registered during the measurements.

GLP compliance:

no

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source: Solvay Specialty Polymers S.p.A (Manufacturer)
- Lot/batch number of test material: OFC_898608
- Name as reported on the test report: Labware 5426970
- Purity: 99.5% +- 0.5% (w/w) (NMR uncertainty )

Dissociating properties:

yes

pKa:

0.88

Remarks on result:

other: at room temperature

pKa TEST 1	pKa TEST 2	pKa TEST 3
0,88	0,52	0,78
0,86	0,8	0,78
0,89	0,88	0,75
0,90	0,88	0,6
0,88	0,88	0,75
0,88	0,79	0,73
0,87	0,88	0,83
0,87	0,88	0,78
0,89	0,9	0,76
0,84	0,92	0,87

mean = 0,83

std dv = 0,08

Conclusions:

pKa = 0.83 (dev.st = 0.08).
The substance is a strong acid.

Executive summary:

The determination of the dissociation constant requires a measure of the concentrations of the dissociated and undissociated forms of the chemical substance and their pH dependence.
A test solution was prepared by weighting approximately 0.25 g (0.0001g precision) of test substance then solubilized in 50 ml of bidistillated water.
The test solution was titrated with the standard base solution (NaOH 0.1 N), measuring the pH after each addition of titrant.
The pKa is calculated for 10 measured points on the titration curve across the half-neutralization point (HP1) and before neutralization point (EP1). The test was repeated 3 times on three different replicates.

The measured pKa is 0.83 (dev.st = 0.08).

Description of key information

In the key study two different samples were tested. The results are respectiverly pKa = 1.16 (dev.st = 0.07) and pKa = 0.83 (dev.st = 0.08). The two results are consistent, in fact the batch with higher pKa has a slightly higher level of impurities which affected the tritation volume.

A third study is available, which is judged of reliability K4 due to the absence of information on the tested batch and of detailed information on the applied method. 

All the available data indicates that F-DIOX Acid is a strong acid.

The selected Key value is the one obtained for the key study conducted on the batch with the higher level of purity.

Key value for chemical safety assessment

pKa at 20°C:

0.83