Formaldehyde → Dimethyl alpha-hydroxymethyl-alpha-fluoromalonate

Beteiligte Stoffe

Reaktionsschritte

48 g (0.48 mol) of potassium bicarbonate were dissolved in 535 g (6.59 mol) of aqueous formaldehyde solution (37% strength by weight) in a 4-liter glass flask. 841 g (5.6 mol) of dimethyl α-fluoromalonate were added dropwise to this solution., with stirring, in the course of 31/2 hours; the temperature was kept meanwhile within the range from 20° to 25° C. Stirring was continued for 2 hours at the same temperature, and during this time dimethyl α-hydroxymethyl-α-fluoromalonate was precipitated in the form of a colorless solid. 2,500 g of an aqueous, saturated solution of ammonium sulfate were then added to the reaction mixture, which was then extracted with methylene dichloride. The extraction solution was dried by means of anhydrous sodium sulfate. 906 g (90% of theory) of dimethyl a-hydroxymethyl-α-fluoromalonate were obtained after removing the methylene dichloride by distillation (bath temperature 40° C., 25 mbar).

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