Zeolite-catalyzed solvent-free transoximation of carbonyl compounds and cyclohexanone oxime

Abstract

Carbonyl compounds were transformed to oximes by the transoximation reaction with HY zeolite under solvent-free conditions through the reaction–distillation coupling process. First, single-factor experiments were conducted to investigate the effects of temperature, feed molar ratio, catalyst loading, and vacuum degree on the yield of cyclododecanone oxime (CDOX). Secondly, the Plackett–Burman screening and Box–Behnken response surface methodology were further utilized to optimize the process parameters, and the optimal conditions were obtained: a temperature of 90 °C, a cyclododecanone (CDON)/cyclohexanone oxime (CHO) molar ratio of 1.4 : 1, a catalyst loading of 1.6 g, and a vacuum degree of 240 mbar. Under these conditions, the yield of CDOX can reach 99.45%, which is similar to the predicted value of 99.76% by response surface methodology. Furthermore, a large pore size and Brønsted acidity of the zeolite are essential for good catalytic performance, and HY-5 shows the highest yield of CDOX under the reaction–distillation process. The catalyst can be recovered and reused several times, and the mechanism was proposed.