Separation of an ester and ketone

[khatereh]

I have a mixture of an aromatic diketone and its anhydride. I was not able to separate them with column chromatography as they came out almost at the same time and the process was so time consuming in the case of using longer column. I also have to work with small amount of materials and most of my product was wasted in column..

I was wondering if anybody knows a better separation method?

[Knumbnuts]

What is the anhydride of an aromatic diketone? Perhaps you could elaborate.

[khatereh]

I draw the two compounds in attached file. R is an aromatic ring

[Knumbnuts]

Treat the mixture with base, hydrolyse the anhydride, remove as the sodium salt by extraction into water. Crystallise the diketone from the organic phase.

Edited March 17, 2013 by Knumbnuts

[khatereh]

Could you please explain more?Do you mean this:

I should add basic aqueous solution of a sodium salt to it, Then dicarboxylic acid will form which is probably soluble in water. right? and diketone will remain?

 

Thanks for your reply by the way

[Knumbnuts]

Treat the mixture with aqueous sodium hydroxide. This should hydrolyse the anhydride and leave the acids as their sodium salts. These should be soluble in water, and after an extraction of the basic solution with an organic solvent, which is not miscible with water, you should have your diketone in the organic layer. Separate the layers and then evaporation of the solvent will deliver the diketone, hopefully pure enough that it crystallises.

[khatereh]

Thank you for your reply