Vapor Phase Beckmann Rearrangement over a High Silica MFI Zeolite

Ichihashi, Hiroshi

doi:10.1002/chin.200426262

Cited by 1 publication

(4 citation statements)

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“…Even with a very high silica MFI zeolite (Si/Al atomic ratio =147 000), which was expected to possess almost no acidity, 100% cyclohexanone oxime conversion and 79.6% ε-caprolactam selectivity were achieved. 6 So, it was concluded that the active sites of the catalyst are extremely weak acid sites that might not be detected by ammonia temperature programmed desorption (TPD) measurements. In a kinetics study Komastu et al 7 found that desorption of ε-caprolactam was the slowest reaction process in Beckmann rearrangement over zeolite.…”

Section: Catalyst Preparation Parametersmentioning

confidence: 99%

“…An increasing trend of cyclohexanone oxime conversion and ε-caprolactam selectivity was observed with increasing atomic ratio of Si/Al. Even with a very high silica MFI zeolite (Si/Al atomic ratio =147 000), which was expected to possess almost no acidity, 100% cyclohexanone oxime conversion and 79.6% ε-caprolactam selectivity were achieved . So, it was concluded that the active sites of the catalyst are extremely weak acid sites that might not be detected by ammonia temperature programmed desorption (TPD) measurements.…”

Section: Catalyst Preparation Parametersmentioning

confidence: 99%

“…It helped to keep the ε-caprolactam selectivity on a high level through a long turnover stream . When methanol was cofed with cyclohexanone oxime, dimethyl ether was not formed due to the less acidic high silica MFI …”

Section: Catalyst Preparation Parametersmentioning

confidence: 99%

“…8 When methanol was cofed with cyclohexanone oxime, dimethyl ether was not formed due to the less acidic high silica MFI. 6 In B-MFI, water molecules interacted with Brønsted acid sites and stabilized the tetrahedral coordination of boran, whereas upon water removal, the SiO(H)−B bond was weakened and boron rearranged in a trigonal coordination. 39−41 After steaming with deionized water, boron atoms were extracted from the zeolite lattice forming BO 3 extraframework species; a progressive treatment with dilute acid solution removes extraframework BO 3 .…”

Section: Catalyst Preparation Parametersmentioning

confidence: 99%

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Comprehensive Study for Vapor Phase Beckmann Rearrangement Reaction over Zeolite Systems

Kumar

Chowdhury

2014

Ind. Eng. Chem. Res.

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Replacement of homogeneous catalysis systems by heterogeneous catalysis systems is widely accepted throughout academia and industry due to ecological concerns, difficulty of separations, and nonrecyclability of homogeneous catalysts. Among several heterogeneous catalysts, the zeolite system has been focused extensively on vapor phase Beckmann reactions for a few decades. In this article a review of the factors affecting the cyclohexanone oxime conversion and ε-caprolactam selectivity over different zeolite systems is presented. It can be concluded that several catalyst preparation parameters such as Si/Al ratio, different metal/nonmetal loading, micropore size, and postsynthesis treatment as well as catalyst preparation parameters like temperature and solvent have crucial roles in deciding cyclohexanone oxime conversion and product selectivity over microporous zeolite catalysts. In the last section, an attempt was made to summarize the reaction mechanism for this reaction over zeolite catalyst systems. This thorough study might be useful for efficient design of a microporous zeolite system toward Beckmann rearrangement reactions.

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Section: Catalyst Preparation Parametersmentioning

confidence: 99%

Section: Catalyst Preparation Parametersmentioning

confidence: 99%

Section: Catalyst Preparation Parametersmentioning

confidence: 99%

Section: Catalyst Preparation Parametersmentioning

confidence: 99%

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