Potassium trifluoroacetate

Phototransformation in air

Administrative data

Endpoint:

phototransformation in air

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

Not specified

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study not performed according to international guideline nor under GLP. However, the methodology is scientifically acceptable and the report is sufficiently well documented..

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

1995

Materials and methods

Principles of method if other than guideline:

An investigationof the iron (a ubiquitous constituent of atmospheric drops) catalysed photodecarboxylation of haloacid compounds including TFANa was performed to help to determine if there are possible atmospheric reactions of these compounds. Aqueous solutions containing ferric ions and chloro- or fluoroacetates were photolyzed by light with wavelengths greater than 300 nm. In conjunction with monitoring the photolytic disappearrance of Fe(III)-halocetate spectrophotometrically, the concomittant decrease in the concentration of haloacetate was followed by anion chromatography. Another approach to determine the extent of haloacetate mineralization was used measuring the amount of CO2 formed.

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Sodium trifluoroacetate

EC Number:

220-879-6

EC Name:

Sodium trifluoroacetate

Cas Number:

2923-18-4

Molecular formula:

C2HF3O2.Na

IUPAC Name:

sodium trifluoroacetate

Details on test material:

The test materials used were the purest grade available and NaTFA was obtained from Aldrich.

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
See the endpoint study summary "Environmental fate and pathways" for the read-across justification.

Study design

Light source:

Xenon lamp

Light spectrum: wavelength in nm:

> 300

Relative light intensity:

0

Results and discussion

% Degradation

% Degr.:

0.92

Sampling time:

42 min

Test condition:

5 mmol/L TFA; 1.2 mmol/L Fe3+, Io=2E-7 eins.s-1.mL-1 at pH 4-5. Photolysis followed by monitoring of CO2. Further photolysis did not generate additional amount of carbon dioxide.

Transformation products:

yes

Identity of transformation products

No.:

#1

Reference

Reference substance name:

Unnamed

IUPAC name:

dioxomethane

Inventory number:

InventoryMultipleMappingImpl [inventoryEntryValue=EC 204-696-9]

CAS number:

124-38-9

Any other information on results incl. tables

- Photolysis of TFA resulted in the formation of 92 µmol/L of CO2 after 42 min corresponding to 0.92%, but further photolysis did not generate additional amount of carbon dioxide.

- The rate of loss of TFA is lower than 1.

- Degradation of haloacetates can be due to direct photodecarboxylation or the photolytic generation of hydroxyl radicals.

- The rate of the reaction of OH with TFA is too slow to measure. This is in agreement with the relative inertness of TFA to ferric-assissted carbon photodecarboxylation.

- For all the haloacetates except TCA and TFA, the amount of halide formed, within the experimental error, quantitatively corresponded to the amount of the respective haloacetate mineralized.

Applicant's summary and conclusion

Validity criteria fulfilled:

not applicable

Conclusions:

- Photolysis of TFA resulted in the formation of 92 µmol/L of CO2 after 42 min corresponding to 0.92% degradation, but further photolysis did not generate additional amount of carbon dioxide.
- The rate of loss of TFA is lower than 1.
- The rate of the reaction of OH with TFA is too slow to measure.

Executive summary:

Aqueous solutions containing ferric ions and chloro- or fluoroacetates were photolyzed by light with wavelengths greater than 300 nm. Significant variation in the extent of reaction was observed, with the totally halogenated acetates degraded very little in the course of the experiments. Photolysis of TFA resulted in the formation of 92 µmol/L of CO2 after 42 min corresponding to 0.92% degradation, but further photolysis did not generate additional amount of carbon dioxide. The rate of loss of TFA is lower than 1. Degradation of haloacetates can be due to direct photodecarboxylation or the photolytic generation of hydroxyl radicals. The rate of the reaction of OH with TFA is too slow to measure. This is in agreement with the relative inertness of TFA to ferric-assissted carbon photodecarboxylation. For all the haloacetates except TCA and TFA, the amount of halide formed, within the experimental error, quantitatively corresponded to the amount of the respective haloacetate mineralized.