固体磺酸催化环己酮肟液相Beckmann重排制己内酰胺-化学工程专业论文.docxVIP

II II Abstract Caprolactam is an important organic chemical raw material. It is widely used to automobile, spinning, medicine, electron and machinery trades. At present, the last step of commercial processes for caprolactam is Beckmann rearrangement of cyclohexanone oxime Catalyzed by fuming sulfuric acid or concentrated sulfuric acid. A large amount of ammonium sulfate as by-product was formed in this process. And brings equipment corrosion, high cost etc. Vapor-phase Beckmann rearrangement over solid acid catalysts can avoid ammonium sulfate, however, because of its high reaction temperature, catalysts can easily inactivate. In this work, we explored the liquid-phase Beckmann rearrangement of cyclohexanone oxime under mild condition by using solid sulfonic acid instead of liquid fuming sulfuric acid as catalysts. Different catalyzed systems of solid sulfonic acid were examined. First of all, the liquid-phase Beckmann rearrangement over D-72 sulfonic acid resin (4.2mmol/g of acidity) had been researched. The influences of solvent, reaction time, reaction temperature, amount of catalyst etc were examined. what is more, the optimized reaction conditions and the reuse of catalyst was investigated. Results indicate that under the condition of cyclohexanone oxime 1.0g, D-72 sulfonic acid resin 0.5g, 0.1g/ml of consentration of oxime (DMSO as solvent), at 130℃ for 6h, cyclohexanone oxime conversion can reach 100% and selectivity of caprolactam reaches 86.24%. This catalyst can be easily separated, and conveniently recovered for recycled use. Cyclohexanone, dimer and trimer of caprolactam were the main by-products under this catalyzed system. Moreover, the liquid-phase rearrangement over Amberlyst-35 sulfonic acid resin (4.2mmol/g of acidity) had been explored. The optimized condition were 1.0g of cyclohexanone oxime, 0.5g of Amberlyst-35 sulfonic acid resin, 0.1g/ml of consentration of oxime (DMSO as solvent), at 130℃ for 6h. It can be found that Amberlyst-35 s