Diacetonamine hydrogen oxalate (CAS no.: ) could be produced through the following routes.

A mixture of 200 g. (2 moles) of mesityl oxide and 280 cc. of aqueous ammonia (27 per cent) is placed in a 1-l. round-bottomed flask which is equipped with an efficient mechanical stirrer. The stirrer should be inserted through a stopper in such a way that the flask is nearly air-tight. Because of the heat generated during the reaction it is desirable to keep tap water running over the flask. After stirring for several hours the system becomes homogeneous. When this point is reached the stirring is discontinued, and the well-stoppered flask is allowed to stand at room temperature for three days.

Dry air is blown through the solution to remove the excess of ammonia, and the solution is then dissolved in its own volume of absolute alcohol. A sample of this solution is titrated with standard oxalic acid, litmus being used as an outside indicator. The amount of oxalic acid necessary to form the acid salt is placed in a large evaporating dish and dissolved in 4 l. of 95 per cent alcohol. The amine solution is then slowly run into the acid with constant stirring. During the addition of the last half of the amine solution, the container must be cooled in order to avoid the formation of the neutral oxalate.

The resulting mixture is then heated on a steam cone or an air bath with constant stirring until the temperature of the mixture reaches 70°. The mixture is filtered, while hot, through a previously heated Büchner funnel. The filtrate is immediately placed in a large beaker or evaporating dish for the crystallization of the diacetonamine hydrogen oxalate. The residue is treated with boiling alcohol and filtered, the filtrate containing a small additional quantity of the amine hydrogen oxalate. The mother liquor is distilled until nothing further passes over at 78°, and the residue is allowed to stand for a day in a cool place. The crystals that separate are washed with cold absolute alcohol and dried. A total yield of 285–320 g. (63–70 per cent of the theoretical amount) of product that melts at 126–127° is obtained.