Vapor Phase Beckmann Rearrangement Of Cyclohexanone Oxime Over(Al,B)-MCM-41Zeolites

Liquid phase Beckmann rearrangement reaction, catalyzed with concentratedsulfuric acid, is the main manufacturing process of ε-caprolactam at present. However,equipments corrosion, environmental pollution and raw materials wasting have been abig problem in this process. In order to solve these issues, vapor phase Beckmannrearrangement reaction, using zeolites as catalysts attracts lots of attention.Vapor phase Beckmann rearrangement reaction of cyclohexanone oxime toε-caprolactam was studied over （Al, B）-MCM-41catalysts in this thesis. Two series ofcatalyst were synthesized by the modified fast synthesis method and characterized byXRD, Nitrogen physisorption, FT-IR,27Al MAS NMR, and NH₃-TPD. Therelationship among the Al and B content, acid strength and catalytic activity werediscussed for the catalysts in the reaction. The XRD results indicated that thesynthesized catalysts exhibit typical mesostructural of MCM-41. The FT-IR resultsconfirmed the incorporation of Al and B into the framework. When the mole ratio ofAl/B was0.5, with the increasing of Al and B content, more weak acid sites wereproduced and it was favorable to form caprolactam. When the mole ratio of Si/M was10, the selectivity of caprolactam increased with increasing B content. The catalysthad low activity by adding B only in the MCM-41. The activity of （Al, B）-MCM-41ismainly associated with the content of Al+B in the framework and the amount of weakacid site.Moreover, reaction temperature, reaction time, the amount of ethanol and theheating rate of calcination were chosen as the influencing factors, while relativecrystallinity as response.2IV4-1fractional factorial design method was adopted toexplore the conditions in the synthesis process. Analysis of variance of the16experiments proved that the chosen influence factors and interaction of two factorswere both important influence factors. When the value of four factors was80oC,3h,100mL,0.5oC/min respectively, the crystallinity was highest and the predicted valuewas99.93%in this condition. The result was approved by the reliability test.