Catalytically active and selective centers for production of ɛ-caprolactam through liquid phase Beckmann rearrangement over H-USY catalyst

Ngamcharussrivichai, Chawalit; Wu, Peng; Tatsumi, Takashi

doi:10.1016/j.apcata.2005.04.043

Cited by 30 publications

(13 citation statements)

References 57 publications

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“…The effect of the strong interaction of the keto-amide complex when compared with the adsorption energy of the N-bound complex points towards the amide molecule possibly obstructing the adsorption of the oxime molecule in the first step of the reaction. This agrees well with the previous experimental data [14] where the conclusion was that the reaction on the Brønsted acid of FAU is very active in the conversion of the cyclohexanone oxime into lactam, but a problematic desorption step is encountered.…”

supporting

confidence: 92%

Vapor‐Phase Beckmann Rearrangement of Oxime Molecules over H‐Faujasite Zeolite

Sirijaraensre

Limtrakul

2006

ChemPhysChem

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The Beckmann rearrangement (BR) plays an important role in a variety of industries. The mechanism of this reaction rearrangement of oximes with different molecular sizes, specifically, the oximes of formaldehyde (H(2)C=NOH), Z-acetaldehyde (CH(3)HC=NOH), E-acetaldehyde (CH(3)HC=NOH) and acetone (CH(3))(2)C=NOH, catalyzed by the Faujasite zeolite is investigated by both the quantum cluster and embedded cluster approaches at the B3LYP level of theory using the 6-31G (d,p) basis set. To enhance the energetic properties, single point calculations are undertaken at MP2/6-311G(d,p). The rearrangement step, using the bare cluster model, is the rate determining step of the entire reaction of these oxime molecules of which the energy barrier is between 50-70 kcal mol(-1). The more accurate embedded cluster model, in which the effect of the zeolitic framework is included, yields as the rate determining step, the formaldehyde oxime reaction rearrangement with an energy barrier of 50.4 kcal mol(-1). With the inclusion of the methyl substitution at the carbon-end of formaldehyde oxime, the rate determining step of the reaction becomes the 1,2 H-shift step for Z-acetaldehyde oxime (30.5 kcal mol(-1)) and acetone oxime (31.2 kcal mol(-1)), while, in the E-acetaldehyde oxime, the rate determining step is either the 1,2 H-shift (26.2 kcal mol(-1)) or the rearrangement step (26.6 kcal mol(-1)). These results signify the important role that the effect of the zeolite framework plays in lowering the activation energy by stabilizing all of the ionic species in the process. It should, however, be noted that the sizeable turnover of a reaction catalyzed by the Brønsted acid site might be delayed by the quantitatively high desorption energy of the product and readsorption of the reactant at the active center.

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supporting

confidence: 92%

Vapor‐Phase Beckmann Rearrangement of Oxime Molecules over H‐Faujasite Zeolite

Sirijaraensre

Limtrakul

2006

ChemPhysChem

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“…Ngamcharussrivichai et al reported that the addition of water positively impacts the selectivity during liquid phase Beckmann rearrangement using an H-Y zeolite catalyst [63,64]. However, the observed effect of water on the activity and selectivity of Al-MSPs in this work was found to be more significant.…”

Section: Catalytic Tests In Beckmann Rearrangement Of Cyclohexanone Oximecontrasting

confidence: 66%

Synthesis and Catalytic Performance of Aluminium‐containing Mesoporous, Spherical Silica Particles

Weissenberger

Machoke

Kolle

et al. 2021

Chemie Ingenieur Technik

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A one-pot synthesis of aluminium-containing mesoporous silica particles (Al-MSPs) utilizing polyvinyl alcohol (PVA) as steric stabilization agent is reported. PVA prevents particle agglomeration even when the ionic aluminium source is present in the synthesis mixture. Silicon and aluminium sources were utilised completely, resulting in high yield and easy adjustment of the Si/Al ratio. The Al-MSPs showed a spherical morphology, high surface area and were active for the liquid-phase Beckmann rearrangement of cyclohexanone to caprolactam.

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“…A major industrial strategy is to develop solid acids for the liquid-phase Beckmann rearrangement [4][5][6][7][8][9][10][11][12][13][14][15][16][17]. It can produce CPL at moderate temperature (373-403 K) with less catalyst deactivation [8,18], and the flexibility to replace homogeneous catalyst in existing plants, in comparison to that in the vapor-phase [19][20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

“…Using a solvent (e.g. Bezonitrile (PhCN)) with suitable polarity and basicity can enhance the catalytic activity and prevent catalyst deactivation [8,11,18]. Moreover, poisoning strong BAS and Lewis acid sites (LAS) via pre-adsorption of guest molecules (e.g.…”

Section: Introductionmentioning

confidence: 99%

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Acidity enhanced [Al]MCM-41 via ultrasonic irradiation for the Beckmann rearrangement of cyclohexanone oxime to ɛ-caprolactam

Wang

Ling

Jun

et al. 2018

Journal of Catalysis

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Using solid acid catalysts to replace liquid acids in the liquid-phase Beckmann rearrangement of cyclohexanone oxime (CHO) into -caprolactam (CPL) is crucial for the environmentally friendly production of synthetic fibers, such as Nylon-6. In this work, we prepared aluminum-containing MCM-41 catalysts under ultrasonic irradiation with various Si/Al ratios for this purpose. Quantitative 1 H MAS NMR investigations show that ultrasonic irradiation significantly promotes the formation of active Brønsted acid sites (BAS) on the [Al]MCM-41 catalysts up to 8 times higher than those prepared at the same conditions without ultrasonic irradiation, and up to 12 times higher BAS density than those reported in the literatures. The catalytic performance of [Al]MCM-41 catalysts can be strongly improved with increasing the BAS density, particularly to the ratio of BAS/(weakly acidic SiOH groups). Moreover, [Al]MCM-41 catalysts dehydrated at 393 K obtained two time higher CHO conversion and CPL yield than that dehydrated at 473 K. Hydrogen-bonded water molecules retained at low dehydration temperature may block surface SiOH groups and suppress the side reaction for cyclohexanone. With higher BAS density resulting from ultrasonic irradiation, [Al]MCM-41 catalyst (Si/Al = 10) in this work obtained the highest CPL yield among all [Al]MCM-41 materials reported for liquid-phase Beckmann rearrangement up to now. Finally, the reusability of [Al]MCM-41 catalyst was tested and no significant activity loss can be observed after five reaction cycles.

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Catalytically active and selective centers for production of ɛ-caprolactam through liquid phase Beckmann rearrangement over H-USY catalyst

Cited by 30 publications

References 57 publications

Vapor‐Phase Beckmann Rearrangement of Oxime Molecules over H‐Faujasite Zeolite

Vapor‐Phase Beckmann Rearrangement of Oxime Molecules over H‐Faujasite Zeolite

Synthesis and Catalytic Performance of Aluminium‐containing Mesoporous, Spherical Silica Particles

Acidity enhanced [Al]MCM-41 via ultrasonic irradiation for the Beckmann rearrangement of cyclohexanone oxime to ɛ-caprolactam

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