The Catalysis of Vapor-Phase Beckmann Rearrangement for the Production of ε-Caprolactam

Development and Industrialization of the Vapor-Phase Beckmann Rearrangement Process

“…Therefore, it is natural to think that the active sites are located inside the micropores. 18 In order to confirm this possibility, we compared the molecule's size and the size of the pore mouth. Figure 12 shows a comparison of the cyclohexanone oxime or caprolactam molecule's size and that of the pore mouth.…”

“…Figure 12 shows a comparison of the cyclohexanone oxime or caprolactam molecule's size and that of the pore mouth. 18 The geometries of the molecules were fixed by the help of D mol cube quantum mechanical program. 19 Cyclohexanone oxime seemed to be able to enter the micro- Fig.…”

“…Comparison of the size of cyclohexanone oxime and that of zeolite aperture. 18 pore, but it seemed impossible for caprolactam to go through the pore mouth, indicating that caprolactam is not formed in the inner part of the micropores. We believe that the active sites are not in the inner and deep parts of micropores, but on the external surface or in the inner parts close to the mouth of the micropores.…”

“…Table 2 shows the results of these reactions. 18 In this experiments, methanol was not used, and therefore, selectivities were low. Cyclopentanone oxime, which is smaller than cyclohexanone oxime, gave the amide product with a high selectivity.…”

“…20 Figure 13 shows our image of the active site. 18 This figure is a view of a cyclohexanone oxime molecule coordinated to nest silanols in a straight channel, seen from its side section. About half of the cyclohexanone oxime molecule is outside of the aperture.…”