Organic Solvent-Free Process for Cyclohexanone Ammoximation by a Ceramic Membrane Distributor

Cyclohexanone ammoximation with cyclohexanone, ammonia gas, and hydrogen peroxide over titanium silicalites-1 catalysts requires a large amount of tert-butanol as solvent, which needs to be recycled in industry and increases the separation costs. A novel organic solvent-free process for cyclohexanone ammoximation was developed, in which a porous ceramic membrane distributor was introduced to the reactor and used for the micro-scale distribution of H₂O₂. Plenty of tiny H₂O₂ drops were produced with the membrane distributor to strengthen the mixing between water phase and organic phase in the cyclohexanone ammoximation without organic solvents, resulting in enhanced oxime selectivity. The membrane operating and reaction conditions were optimized, and the ceramic membrane exhibited excellent thermal and chemical stability.