Beckmann rearrangement liquid-phase reaction

The control of selectivity in the vapor phase Beckmann rearrangement seems to be difficult this can be ascribed to the drastic experimental conditions required. Liquid-phase reactions over heterogeneous catalysts have been investigated. The Beckmann rearrangement of cyclohexanone oxime in the liquid phase was performed under reflux conditions in a variety of solvents [44]. When chlorobenzene was used solvent conversion and selectivity increased with temperature up to 405 K. From plots of conversion against time it was concluded that catalyst deactivation under liquid-phase conditions is small, in contrast with the rapid deactivation observed when the reaction was conducted in the vapor phase. 

Chung et al reported the liquid phase Beckmann rearrangement of 4-hydroxyacetophenone oxime using zeolite H p catalyst. The reaction was found to be an example of active solvent participation. A solvent having higher dielectric constant or more polar nature is preferred in the rearrangement step. 

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