Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 200-929-3
CAS number: 76-05-1
The key value of the Henry's Law constant for trifluoroacetic acid was calculated by the average of two measured values reported in two valid peer reviewed studies. In cloud and fog, CF3COOH will partition entirely into the aqueous phase. For atmospheric aerosols, at temperatures less than 15°C, significant proportions of CF3COOH may reside in both phases and partitioning will be sensitive to the composition of the aerosol and concentration of the dissolved solutes.
Two reliable studies on Henry's Law constant measurement published in
peer reviewed jounals are available. In the first study, an experimental
determination of the Henry's law constant of trifluoroacetic acid is
described, and the implications for its partitioning and removal from
the atmosphere are discussed. Equilibrium partial pressures CF3COOH over
aquous solutions containing the dissolved acid were measured at a
temperature of 298.15 K (25°C) using the pH changes of the solution and
the results of separate calibration experiments which relate change in
pH to added acid concentrations . KH was 8950 +/- 100 mol/kg/atm for pKa
= 0.47 corresponding to 1.1E-02 Pa.m3.mol-1. In cloud and fog, it is
clear that CF3COOH will partition entirely into the aqueous phase. For
atmospheric aerosols, the situation is more complex. At temperatures
less than 15°C, significant proportions of CF3COOH may reside in both
phases and partitioning will be sensitive to the composition of the
aerosol and concentration of the dissolved solutes.
In the second study, equilibrium partial pressures of trifluoroacetic
acid over aqueous trifluoroacetic acid test solutions were determined at
278.15, 288.15 and 298.15 K. The concentration of undissociated
trifluoroacetic acid in each test solution was determined by means of
attenuated total reflection IR spectroscopy and window factor analysis.
The Henry's law constant of trifluoroacetic acid (KH) at 298.15 K was
determined to be 5800 +/- 700 mol/dm3/atm corresponding to 7.13E-03
Pa.m3.mol-1. The KH value at 298.15 K was 0.65 times the reported value
by Bowden et al. (1996) for pKa = 0.47 and it was equal to that for pKa
The key value of the Henry's Law constant for trifluoroacetic acid was
calculated by the average of the two valid measured values corresponding
to 0.009 Pa.m3.mol-1.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
Welcome to the ECHA website. This site is not fully supported in Internet Explorer 7 (and earlier versions). Please upgrade your Internet Explorer to a newer version.
Do not show this message again