[fran008]

How would you convert

CH3COCH3 into CH3COOH?

I tried thinking about an iodoform but that will remove two carbons. I also thought about the possibility of a Hofmanndegredation, but how would i bring the ketone to an amide first?

[HP]

Acetone vapour is thermolyzed(cracked) at 700C, Cu in ketene generator the so known "ketene lamp" to ketene and methane:
CH3COCH3-->CH2=C=O + CH4
CH2=C=O + H2O--> acetic acid

[AWK]

Beckmann rearrangement of oxime
Bayrer-Villiger oxidation

[movies]

Beckmann rearrangement of oxime
Bayrer-Villiger oxidation

Beckmann rearrangement would get you the amide!  I suppose you could still hydrolyze it, but I'd rather hydrolyze an ester than an amide any day.

[HP]

Its my duty to mention that the ketene route of acetic acid from acetone is dangerous procedure because of the very high toxicity of ketene which is as toxic as the phosgene!!! Experiments only under well ventilated hood! By the way do you think its possible Favorsky type rearangement of bromoacetone with NaOH to propionic acid? I mean:
CH3COCH3 + Br2--> CH3COCH2Br (nasty lacrymator )
CH3COCH2Br + NaOH --> CH3CH2COONa after Favorsky rear

[Albert]

I think you'd yield acrylic acid rather than propionic.

[HP]

Why do you think so? - the mechanism this reaction is cleavage the Br-athom from CH2group to form carb cation RHOC(O:-)CH2+--> and then R goes to CH2+ to form RCH2COOH, well and if R=CH3 then the product is CH3CH2COOH i think. In fact when i was student i wonder if this reaction with bromoacetone possible but didnt ask my tutour - Great a mistake i think

[Albert]

You're probably right, fellow. I've only used Favorskii reaction in the synthesis of cortisone (where it leads to a double bond), so I don't have enough experience for what concerns its possible application in different syntheses.

[HP]

Yah Favorskii reaction very useful for colegues in pharmacy. It will be nice to picture us your cortison synthesys if not rather complicated Of course some steroids are not steroids without double bond and then uncle Favorskii welcome them   I am not sure if Favorskii rearangement is the same thing as Favorsky reaction though may be similar...In the Fav reaction mechanism there i saw CH:- not CH2+ and the final acid produt is COO:- not directly COOH(ofcourse if base stechiometric).See:
http://www.organic-chemistry.org/frames.htm?http://www.organic-chemistry.org/namedreactions/favorsky-reaction.shtm
If some one know the difference F-reaction and F-rearangement pls feel welcome in discussion.

[engineer]

oxidising acetone (CH3COCH3) using powerful oxidizing agent such as KMnO4 yields CH3COOH and HCOOH.
however the reaction takes some time because ketones are relatively stable to further oxidation because a strong C-C bond must be broken in the process.