Hoechst Aktiengesellschaft

Georg Stuhlmuller

Detlef Kampmann

Process for the continuous preparation of 2,2,6,6-tetramethylpiperidine. The reduction of triacetonamine with hydrazine also succeeds continuously by reactive distillation if the hydrazone is first formed and this is continuously transported to the distillation bottoms comprising a high-boiling solvent and an alkali at the base of a distillation column and the resulting 2,2,6,6-tetramethylpiperidine is distilled off as an azeotrope. In this procedure a hydrazine/triacetonamine ratio of 1.5:1 to 2.0:1 is sufficient, in comparison with the conventional synthesis, the product yield being able to be considerably increased (&gt;90%). Moreover, the amounts of alkali and solvent used can be considerably reduced.

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Gablingen, Germany

Georg Stuhlmuller