Sciencemadness Discussion Board

Oxidising alcohols into carboxylic acid with KMnO4

azg - 26-4-2014 at 08:19

I read on WikiPedia
http://en.wikipedia.org/wiki/Oxidation_of_primary_alcohols_t...
that Potassium Permanganate effectively oxidizes alcohols, di-ols, etc. It also said the reaction is carried out in a suspension or solution of KOH or NaOH. But the product will react with the base. It said that the reaction can be carried in neutral conditions at a cost of long reaction time.

Also, I read that MnO2 precipitate is formed.

So, do you guys know how much time the reaction will require without strong base ? Is it easy to separate the MnO2 precipitate via decantation ?

Chemosynthesis - 26-4-2014 at 12:39

Since no one knows what your reaction is, specifically, the answer is "no."

azg - 26-4-2014 at 19:28

Quote: Originally posted by Chemosynthesis  
Since no one knows what your reaction is, specifically, the answer is "no."


KMnO4 is stirred in alcohols to get respective carboxylic acids. It oxidizes alcohols to get carboxylic acids. Do you know how much time will this take ?

Chemosynthesis - 26-4-2014 at 19:39

Quote: Originally posted by azg  

KMnO4 is stirred in alcohols to get respective carboxylic acids. It oxidizes alcohols to get carboxylic acids. Do you know how much time will this take ?


That's not a specific reaction with actual reagents. That's a generalized example, so again... no. It's reactant-specific.

DraconicAcid - 26-4-2014 at 20:05

Quote: Originally posted by Chemosynthesis  
Quote: Originally posted by azg  

KMnO4 is stirred in alcohols to get respective carboxylic acids. It oxidizes alcohols to get carboxylic acids. Do you know how much time will this take ?


That's not a specific reaction with actual reagents. That's a generalized example, so again... no. It's reactant-specific.


And temperature dependent. And concentration dependent. And solvent dependent. And, and, and....

Chemosynthesis - 26-4-2014 at 20:34

Quote: Originally posted by DraconicAcid  

And temperature dependent. And concentration dependent. And solvent dependent. And, and, and....

Exactly.

azg, please post with actual reaction conditions or reagents next time, and if not citing peer-reviewed chemical literature, use the "Beginnings" section.

azg - 27-4-2014 at 08:00

25% ethanol in water at room temparature ?

Chemosynthesis - 27-4-2014 at 12:30

Quote: Originally posted by azg  
25% ethanol in water at room temparature ?

It appears your answer is in this article.
J. Am. Chem. SOC. 41, 1267 (1919). pp 1267–1285


You may also consider using acidic conditions if possible.
"The oxidation of ethanol by permanganate has been found to obey the rate law v=k[MeCHO][MnO 4 −][H+]"
Reaction Kinetics and Catalysis Letters
1989, Volume 38, Issue 2, pp 313-318