Beckmann Rearrangement of Cyclohexanone Oxime in a Microreactor Setup with Internal Recirculation

• Published in: Chemical engineering & technology 2013-08, Vol.36 (8), p.1387-1394
• Main Authors: Zuidhof, N. T., de Croon, M. H. J. M., Schouten, J. C., Tinge, J. T.
• Format: Article
• Language: English
• Subjects: Austenitic stainless steels; Beckmann rearrangement; Conversion; Cyclohexanone; Cyclooctane solution; Dissolution; Internal recirculation; Microreactors; Oximes; Purity; Solvents; ϵ-Caprolactam
• ISSN: 0930-7516; 1521-4125
• DOI: 10.1002/ceat.201300088

Beckmann rearrangement of cyclohexanone oxime dissolved in cyclooctane with oleum to ϵ‐caprolactam was demonstrated in a microreactor setup with internal recirculation operated in continuous mode. The core of the setup comprised a 316 stainless‐steel micromixer consisting of 17 split‐and‐recombine units connected to a delay loop, a 316 stainless‐steel microchannel reactor with an internal diameter of 0.250 mm and a length of 0.50 m. At 100 °C, the conversion of cyclohexanone oxime was complete and the selectivity towards ϵ‐caprolactam was approximately 99 %. The solvent cyclooctane reduces the observed purity of the produced oleum/ϵ‐caprolactam. This reduction in purity might be a severe hurdle for usage of a solvent on the industrial scale in the Beckmann rearrangement of cyclohexanone oxime in oleum to ϵ‐caprolactam. A microreactor setup with internal recirculation operated in continuous mode was used to demonstrate Beckmann rearrangement of cyclohexanone oxime dissolved in cyclooctane with oleum to ϵ‐caprolactam. At 100 °C, the conversion of cyclohexanone oxime was complete; selectivity towards ϵ‐caprolactam was 99 %. However, cyclooctane as solvent reduced the purity of the produced ϵ‐caprolactam.