Sauron
International Hazard
Posts: 5351
Registered: 22-12-2006
Location: Barad-Dur, Mordor
Member Is Offline
Mood: metastable
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Diacetin Seperation, Interesting Problem
In connection with a research project described in an ongoing thread I have developed a need for ketomalonic acid also known as mesoxalic acid.
The most practical prep of this acid is oxidation (with conc HNO3 in the cold) of 1,3-diacetyl glycerol - better known as diacetin.
Problem is that while diacetin is a cheap chemical commodity, it is sold as a mixture of 1,2 and 1,3-diesters which are apparently bloody near
impossible to fractionate.
This is how Fluka, Acros, and Aldrich all sell the stuff.
So how to seperate?
Well, I have a plan.
TCCA oxidizes secondary alcohols to ketones leaving primary alcohols untouched under same reaction conditions. Therefore, TCCA will oxidize the
2-position of the 1,3 isomer to a carbonyl yielding 1,3-diacetoxyacetone. Now that can be seperated from 1,2-diacetin readily.
I wanted to try this with glycerin but looks like I will get the chance with diacetin. TCCA to the rescue.
I can then proceed with the oxidation, the HNO3 will have less work to do as the carbonyl will already be there.
Anybody see any flaws in my scheme?
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