Ammonoylsis of diethyl oxalate to oxalamide

Oxalamide or ethanediamide, is an organic compound used as a fertilizer. It's also used as an additive in some rocket fuel mixtures to help slow the burning rate. At room tempurature, oxalamide exists as a white solid. When heated past 350 C, it decomposes releasing deadly cyanogen gas. I did plan to use oxalamide for an experimental synthesis of cyanoformamide, but I decided that this was too dangerous.

Oxalamide can be made by the ammonoylsis of diethyl oxalate. This is a quick and very easy synthesis.

First I added 24ml of 25% aqueous ammonia solution to a 100ml beaker. Then using a syringe, I added 10ml of diethyl oxalate. At first the diethyl oxalate just formed a bottom layer, but after a few seconds, I noticed a white precipitate (presumably oxalamide) beginning to form. I began stirring the mixture and rapidly more oxalamide precipitated. The mixture got thicker as the precipitate built up. After about 1 minute of stirring, the mixture had become a thick white paste. Once this point was reached, I transferred the pasty mixture on to a sheet of paper to dry. After drying, I was left with 6.42g of a white powder, which is almost definitely oxalamide. If pure, this represents a 99% yield!

 A nice feature of the reaction is that oxalamide is the only non-volatile solid involved. This means a fairy pure product can (in theory) be obtained just by allowing the mixture to dry. The only thing that could contaminate the product is unreacted diethyl oxalate. For this reason, I used a 10% excess of ammonia solution to ensure all the diethyl oxalate reacted.


(C2H5)2C2O4 + 2 NH3 ==> (CONH2)2 + 2 C2H5OH