Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
Author: Subject: TFA via oxidation of R-1234yf?
Opylation
Hazard to Others
***




Posts: 131
Registered: 30-8-2019
Member Is Offline


[*] posted on 22-9-2020 at 23:09
TFA via oxidation of R-1234yf?


So out of curiosity I wanted to see if there was any easy way to obtain TFA without having to deal with HF and I found an old post about oxidizing R-143 which is 1,1,1-trifluoroethane. Through a little bit of reading I found out that R-143 is being phased out for another refrigerant under the name R-1234yf which just so happens to be 2,3,3,3-tetrafluoropropene. This is itself just trifluoroacetyl fluoride with a methylene group instead of an oxygen. Could this not be easily oxidized to trifluoroacetyl fluoride? Now the HF produced by the hydrolysis to TFA is a bit discerning but using basic KMnO4 should mop up the HF no?

I don’t have plans on performing this anytime soon as I am much too busy however I have been looking at amine oxidations and TFPAA is listed just about everywhere at the oxidizer of choice and even though I was planning on just using performic acid, having another available, easy to come, and useful reagent would be appreciated

R-1234yf (below)

E4C5E37A-A465-4A05-B11D-F651095C54CB.png - 5kB
View user's profile View All Posts By User
Σldritch
National Hazard
****




Posts: 258
Registered: 22-3-2016
Member Is Offline

Mood: No Mood

[*] posted on 23-9-2020 at 00:40


If you are looking for cheap reagents i think air is pretty good. Im planning trying to go for TFA and/or TFA-Chloride with R-134 (1,2,2,2-tetrafluoroethane). I think it has much higher chance of success than R-143 because the hydrodecarboxylation too trifluoromethane is not possible. Hopefully copper or something similar will catalyse the reaction with air. But if you really want to use R-123yf maybe try ozone, it should be next best thing to air in price and ozonolysis of alkenes is well documented.
View user's profile View All Posts By User
Opylation
Hazard to Others
***




Posts: 131
Registered: 30-8-2019
Member Is Offline


[*] posted on 24-9-2020 at 17:54


I like the ozonolysis idea. It looks like that can be formed at -78C which would be below the boiling point of R-1234yf. This could be performed in methanol with a bit of NaOH to neutralize any HF produced or at the very least, hydrolyze any trifluoroacetyl fluoride into TFA. Definitely one to log away for later. It’s kind of scary though when dealing with the possibility of HF as a product
View user's profile View All Posts By User
njl
International Hazard
*****




Posts: 601
Registered: 26-11-2019
Location: under the sycamore tree
Member Is Offline

Mood: ambivalent

[*] posted on 25-9-2020 at 06:01


HF + ozone + fluorocarbon + cryogenic temperatures

Sounds like a party!
View user's profile View All Posts By User
clearly_not_atara
International Hazard
*****




Posts: 2332
Registered: 3-11-2013
Member Is Offline

Mood: Big

[*] posted on 25-9-2020 at 06:16


You should use WO3/H2O2 for this cleavage, not ozone or permanganate. It's simply much safer, which is especially critical when dealing with fluorostuff. See e.g.:

https://www.sciencemadness.org/whisper/viewthread.php?tid=15...




[Edited on 04-20-1969 by clearly_not_atara]
View user's profile View All Posts By User
Opylation
Hazard to Others
***




Posts: 131
Registered: 30-8-2019
Member Is Offline


[*] posted on 1-12-2020 at 06:32


clearly_not_atara that definitely is an interesting oxidation procedure with tungstic acid and hydrogen peroxide. The only concern I have is that R-1234yf is a gas above -30C and hydrogen peroxide is a solid below -2C. I’m not sure how this oxidation reaction would work with a solid aqueous phase.

[Edited on 1-12-2020 by Opylation]
View user's profile View All Posts By User
njl
International Hazard
*****




Posts: 601
Registered: 26-11-2019
Location: under the sycamore tree
Member Is Offline

Mood: ambivalent

[*] posted on 1-12-2020 at 06:59


you could add an inert solvent to form a eutectic
View user's profile View All Posts By User
Opylation
Hazard to Others
***




Posts: 131
Registered: 30-8-2019
Member Is Offline


[*] posted on 2-12-2020 at 19:05


You're totally right, I wasn't thinking about the H2O-H2O2 mixture freezing point which at 40% is about -40°C. This is very interesting indeed. I'm going to have to put this on my to-do list
View user's profile View All Posts By User

  Go To Top