A LOW TEMPERATURE BECKMANN REARRANGEMENT WITH SO3 INCLUDING SEPARATION OF CAPRIMIDYL SULFATE AS A NEW COMPOSITION

Cyclohexanone oxime can be rapidly and safely converted to caprolactam at low temperatures by use of complexed SO3. All complexing agents do not work. Under these mild conditions, it is possible to use only equimolar amounts of SO3 and thereby to isolate the previously hypothetical “caprimidyl sulfate” intermediate as a new composition of matter. Reaction conditions leading to best lactam yields are presented. Aromatic oximes can also be rearranged by use of triethyl phosphate complexing, which deactivates the SO3 sufficiently so that it does not react with the aromatic ring. Aldoximes undergo dehydration rather than rearrangement. © 1968, American Chemical Society. All rights reserved.