Sciencemadness Discussion Board

Thermal Decarboxylation - Alkyl Phenyl Ketones

Organikum - 22-2-2005 at 23:16

The attached articles refer to the production of ketones by thermal decarboxylation. The second one in special refers to the production of acetophenone and propiophenone from iron acetetate or propionate and benzoate.
The method for sure applies also to the production of phenyl-2-propanone from PAA and iron acetate.
The iron salts can also be prepared from iron oxides - black iron oxide as used as cement-pigment comes to mind here and acetic acid of less than 65% strength.

The practical method is similar to the making of benzene from sodium benzoate and NaOH as described by me in the "benzene" thread.

Articels courtesy lugh.

Attachment: davis_ferric.djvu (92kB)
This file has been downloaded 1698 times

frogfot - 23-2-2005 at 09:51

Thanks for this good info!! I didn't know one could use usual glass equipement for this.. gonna try this out once I get some heavy carboxylic acids.
Maby it's worth to try this with fatty acids.. They don't mentions any yelds with really long acids, like say stearic acid..

FriendlyFinger - 18-2-2006 at 00:54

I can't download this file, It doesn't seem to be there. Does anyone have another link?

Thanks,
FF

solo - 18-2-2006 at 04:49

I reloaded the file again........solo

Attachment: davis_ferric.djvu (92kB)
This file has been downloaded 1234 times

leu - 18-2-2006 at 06:10

You have to right click, select save as and rename the file extension to djvu to download and open it, or you can download the same two articles in the Wet Dreams thread for literature requests from this and other forums :D

FriendlyFinger - 22-2-2006 at 00:22

Sorry, can't find them at wetdreams and definately can't rename after right clicking. The computer automatically tries to download then says it can't find it. Fuck I wish I had a brick right now!

FriendlyFinger - 29-4-2006 at 19:24

Could someone please post another link or at least the name of these two articles so I can look for them somewhere else because I simply can't download it! I have tried for hours and hours. I really have.

See where it says " this file has been downloaded 81 times" well that's me, trying 80 times!

please, thanks.

[Edited on 30-4-2006 by FriendlyFinger]

solo - 29-4-2006 at 21:47

Here you go.....................solo

http://rapidshare.de/files/19241162/thermal_decarboxylation_...

Nicodem - 30-4-2006 at 11:40

Quote:
Originally posted by FriendlyFinger
See where it says " this file has been downloaded 81 times" well that's me, trying 80 times!


The next time this hapens to you either use normal HTTP (not HTTPS) access or simply copy the URL link to another window and delete the S from HTTPS. That should do.
It is due to a bug in Internet explorer. :(

FriendlyFinger - 2-5-2006 at 20:52

Well blow me down. Solo, please mail me your shoes, I keep them under my bed!

Thank you very much

FriendlyFinger - 16-5-2006 at 02:33

What's the chance of this reaction working with ordinary non reduced iron powder?

bio2 - 16-5-2006 at 03:21

Iron can be reduced in a few minutes by
being the Cathode in an electrolytic cell.
Turnings in a net or something.

Precipitated Fe should work and scrap iron
is used in industry and works somewhat
less vigorously.

Main thing is relatively oxide free and clean!

FriendlyFinger - 26-5-2006 at 02:26

Oh! How do you do that? I know nothing about electrolytic cells. How much current? what medium do you use? Is there a book you can mention that I can read?

Also can iron propionate be made using iron oxide or is Organikum refering to iron acetate?

solo - 26-5-2006 at 06:49

Principles of Electrochemistry
Jiri Koryta Jiri Dvorak Ladislav Kavan
Publisher: John Wiley & Sons Inc
Publication Date: 1993-05
Number Of Pages: 502

http://www.uploading.com/?get=BJPZU620

Review
Presents electron transfer and double-layer theories in an understandable manner while keeping mathematics to a minimum. Revised and expanded, this edition features a number of new sections which deal with electrochemical materials science, photoelectrochemistry, stochastic processes, novel aspects of ion transfer across biological membranes, biosensors and more.


.........source,

http://anuvinu.blogspot.com/

Organikum - 15-2-2007 at 19:47

Quote:
Originally posted by bio2
Iron can be reduced in a few minutes by
being the Cathode in an electrolytic cell.
Turnings in a net or something.

Precipitated Fe should work and scrap iron
is used in industry and works somewhat
less vigorously.

Main thing is relatively oxide free and clean!


IIRC then the problem of using oxides was solved by somebody at the HIVE, he used lead though, not iron. But the basic principle stays the same I suppose - the formation of the iron salt in the needed oxidation state depends on the concentration of the acid as mentioned in the first post of mine. Using foir example acetic acid of more then 65% strength in the salt formation will give lousy yields (for lead salts and I think the same for iron salts).
Davis mentiones that magnetic black iron oxide as used as cement pigment gives poor yields (at least in one example - 4%). But when the preparation is tweaked then....

[Edited on 16-2-2007 by Organikum]

manimal - 23-11-2009 at 09:45

See here: instead of risking oxidative degradation by recovering iron acetate from solution, it can be made in situ from ferrous sulfate and sodium carboxylate; this would form ferrous carboxylate and sodium sulfate. The NaSO4 would stick around, but may act as a bulking agent and not interfere with the decarboxylation.

[Edited on 23-11-2009 by manimal]

bbartlog - 23-11-2009 at 10:57

And then you have ferrous carboxylate (I would say carbonate), which (I can only assume) you will further treat with acetic acid (or propionic acid)? But why not just use sodium acetate (and benzoate or w/e) in that case and do things in one step? Also, while the carbonate will react so long as benzoic acid and/or propionic acid are used, some other carboxylic acids are weaker and would not be able to displace the CO2.

As for the general procedure, it looks like a variety of metals other than iron would work. The paper mentions the original work done by Friedel using calcium, and I see someone else above mentions using lead. From what I recall about pyrolysis of calcium salts of carboxylic acids (to produce ketones), the temperatures needed are higher than those used for the iron salts in the paper. I don't know whether this is the only reason they used iron.

Too bad about the ortho- effects. Can't do anything neat with salicylates this way.


[Edited on 24-11-2009 by bbartlog]