Organikum (Hive Bee)
11-21-02 18:33
No 382044
      trifluoroacetic acid ?  Bookmark   

Is there a way to sythesize this compound from GAA or by another method within the reach of clandestine chemistry?

shove it to newbee or aquisition if ya like but I got nothing from TFSE or the Net.

the MERCK didnīt help me:

Monograph number:  Title: Trifluoracetic Acid .
CAS Registry number: 76-05-1
Additional name(s): Perfluoroacetic acid
Molecular formula: C2HF3O2
Molecular weight: Percent Composition: C 21.07%, H 0.88%, F 49.99%, O 28,06%
Line Formula: CF3COOH
Literature references: Prepn: F. Swarts, Bull. Sci. Acad. Roy. Belg. 8, 343 (1922); by oxidation of fluorine olefins: A. L. Henne, U.S. pat. 2,371,757 (1945 to du Pont); A. L. Henne et al., J. Am. Chem. Soc. 67, 918 (1945). Improved prepn: A. L. Henne, P. Trott, ibid. 69, 1820 (1947). Photo chemical prepn: R. N. Hazeldine, F. Nyman, J. Chem. Soc. 1959, 387; eidem, ibid. 420. Toxicity and metabolism: M. M. Airaksinen, T. Tammisto, Ann. Med. Exp. Biol. Fenn. 46, 242 (1968). Review: J. B. Milne in Chem. Non-Aqueous Solvents vol. 5B, J. J. Lagowski, Ed. (Academic Press, New York, 1978) pp 1-52.
Properties:  Liquid, sharp biting odor. bp 72.4degrees . mp minus15.4degrees . d 20 1.5351 . Miscible with ether, acetone, ethanol, benzene, CCl 4 , hexane. Strong, non-oxidizing acid. pka 0.3. LD 50 i.v. in mice: 1200 mg/kg (Airaksinen, Tammisto) .
Density: d 20 Boiling point: bp 72.4 Melting Point: minus15.4 
USE: In organic synthesis; dissolves protein when mixed with liquid SO 2 .

now or never
(Chief Bee)
11-21-02 18:57
No 382062
      trifluoroacetic acid  Bookmark   

What fluorinating agents do you have available to you? F2? HF? KF?

The end oxidation product of most organics containing a trifluoromethyl group is trifluoroacetic acid, so if you have one of the newer HFC's available to you, that may be used as a startig material too.

It seems strange to me if you would be able to purchase F2/HF/KF, but not CF3COOH.
(Hive Bee)
11-21-02 20:17
No 382108
      fluoronating agent is HF  Bookmark   

I thought on HF for the fluorination as CaF2 plus conc. H2SO4 gives HF:
CaF2 + H2SO4 = CaSO4 + 2HF
which for its nasty properties is thought to use directly for the fluorination. But is  bubbling the HF in GAA enough? Complete absence of water is understood. Or is an "in situ" preparation possible wherby the HF is in GAA produced by CaF2 and H2SO4?.

Its not on the basic reactions but for to avoid unpleasant experiences.
CaF2 is quite easy available.

Fluorit aka CaF2:


now or never
(Chief Bee)
11-21-02 21:05
No 382125
      I went through the entire American Chemical ...  Bookmark   

I went through the entire American Chemical Society database (JACS, JOC, Chem Rev etc.) as well as Beilstein and couldn't find anything but vapor-phase oxidation of fluorohydrocarbons (and oxidation of CF3-containing organics). Perhaps you could search the US Patent database?
(Chief Bee)
11-21-02 21:55
No 382149
      Trifluoroacetic acid by thermolysis of Teflon
(Rated as: excellent)

Finally, I found an article in Nature from yesteryear, where teflon is thermolyzed at 500°C to yield about 8% trifluoroacetic acid. The high temperatures are needed, as teflon is stable for 2-3 years at ~260°C.

../rhodium/pdf /teflon.thermolysis.pdf

I suppose that isolation of the trifluoroacetic acid is best done by bubbling the effluent gases through Na2CO3(aq) as described, then evaporating the water under reduced pressure to get the sodium salt, followed by acidification with H2SO4 and distilling. (TFA bp 71°C, TFA-H2O azeotrope bp 106°C).

The crude trifluoroacetic acid is then purified by allowing it to stand over P2O5 for 12h, followed by 1.5h reflux. Fractional distillation gives the pure material, bp 71°C. Reference: JACS 86, 5445 (1964)
(Hive Bee)
11-21-02 22:27
No 382163
      thanks Rhodium  Bookmark   

thanks for the effords Rhod, if I find a place where lotīs of TEFLON is used this might be worth a try.
My favorite place for patent searches is down at the moment (espacenet) frown


now or never
(Hive Bee)
11-26-02 10:43
No 383591
      vapor phase isn't so bad  Bookmark   

Preparation of Trifluoroacetic Acid
J. Org. Chem.; 1961; 26(3); 923-925.

I wasn't able to view the whole article (I can't view ACS archives until January) but it looked very promising. 1,1,1-trifluoroethane, air, and water vapor are subjected to a high-voltage discharge to produce trifluoroacetic acid without side reactions. The equipment is certainly within reach of a home experimenter: they used a neon sign transformer, Pyrex tubing, and aluminum foil to build their apparatus (or what of their apparatus I could see on the first page). 1,1,1-trifluoroethane is commercially available as Freon 143a.

But maybe it's not as simple as it first looks. Can somebody grab the full article and see if my enthusiasm is warranted or misplaced?

19th century digital boy
(Chief Bee)
11-26-02 10:48
No 383593
      JOC Article  Bookmark   

../rhodium/pdf /archive/trifluoroacetic.acid.pdf