Vapor Phase Rearrangement of Cyclohexanone Oxime for Ꜫ-Caprolactam Catalyzed by Mixed Metal Oxides

Abstract

The vapor phase rearrangement of cyclohexanone oxime for Ꜫ-caprolactam catalyzed by mixed metal oxides was studied by using a flow reactor under atmospheric pressure. It was found that the most effective catalysts for this reaction were ZnO-WO8 and Bi2O8-WO8 supported on silica-alumina among some mixed metal oxides examined (Table 1, 2). From the data shown in Figures 1, 2 and 3, the optimum preparation conditions of these catalysts were as follows: atomic ratio of Zn/W: 1/2 and that of Bi/W: 2/1, total amount of oxides: 1.5 mg-atom/g of support, calcination temperature: 800°C on ZnO-WO8, and 700°C on Bi208. The optimum reaction conditions were as follows: temperature: 325°C, and W/F: 300g.hr/mol. The maximum yields of e-caprolactam were 87 mol% and 82 mol% on ZnO-WO8, and Bi208-WO8 on silica-alumina catalysts, respectively (Fig. 4, 5). These catalysts keep such a high activity for 12 hr, and the deactivated catalysts are recovered completely fay the calcination at 350°C in an air. © 1977, The Chemical Society of Japan. All rights reserved.