Ammoximation: I. A direct route to cyclohexanone oxime and caprolactam from NH 3, O 2, and cyclohexanone

Abstract

This report describes the first direct synthesis of cyclohexanone oxime and caprolactam from ammonia, air, and cyclohexanone. Most routes to caprolactam employ circuitous routes involving the oxidation of ammonia to oxides of nitrogen followed by a separate step for the reduction of these oxides to hydroxylamine, reaction with cyclohexanone, and then rearrangement of the resulting oxime with H 2SO 4. By using the novel chemistry described herein, it is possible to selectively react cyclohexanone, ammonia, and air to produce the oxime and/or caprolactam in one step: ▪ To date, the best selectivity for oxime is 68%. The reaction is catalyzed heterogeneously over a variety of silicas and aluminas at temperatures ranging from 120 to 250 °C. By using a dual-bed catalyst, we can convert some of the oxime to caprolactam as it emerges from the first bed of catalyst.