Alkyl transfer reactions on solid acids. The disproportionation of ethylbenzene and toluene on H-mordenite and HY zeolites

Mokoena, K.; Scurrell, Michael S.

doi:10.1080/10916466.2018.1463256

Cited by 8 publications

(12 citation statements)

References 18 publications

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“…Characterization. The catalysts were characterized by powder X-ray diffractometer (XRD), field-emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), N 2 adsorption−desorption experiments, inductively coupled plasma atomic emission spectrometer (ICP-OES), 29 Si and 27 Al MAS NMR measurements, X-ray fluorescence (XRF), temperature-programmed desorption of ammonia (NH 3 -TPD), Fourier transform infrared spectra (FTIR), and thermogravimetric (TG) analysis. The details are provided in the Supporting Information.…”

Section: Synthesis Of Mor Zeolitesmentioning

confidence: 99%

“…Mordenite is one of the several zeolites that have been industrially applied, such as in isomerization, , alkylation, − toluene disproportionation, etc. MOR exhibits large 12-membered ring (12-MR) channels along the c -axis, which are intersected by 8-MR channels along the b- axis .…”

Section: Introductionmentioning

confidence: 99%

“…19 It is believed that the existence of seeds facilitates nucleation; thus, more primary particles and smaller zeolite crystals were formed in the seedassisted process. 20,21 Mordenite is one of the several zeolites that have been industrially applied, such as in isomerization, 22,23 alkylation, 24−26 toluene disproportionation, 27 etc. MOR exhibits large 12-membered ring (12-MR) channels along the c-axis, which are intersected by 8-MR channels along the b-axis.…”

Section: Introductionmentioning

confidence: 99%

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Wheel-like Mordenite Nanoassemblies with Shortened Channel Lengths for Improved Catalytic Performance in Dimethyl Ether Carbonylation

Liu,

Wang,

et al. 2023

ACS Appl. Nano Mater.

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To achieve a better catalytic performance, it is of great interest to synthesize nanosized zeolites with reduced internal diffusion limitations. Herein, c-axis shortened wheel-like mordenite nanoassemblies were synthesized. The crystal growth along the [001] direction was successfully inhibited with K + cations as structure breaking agents. The wheel-like crystal is 1.5−2 μm in diameter and 200−300 nm in thickness. The growth of such a unique structure underwent a nonclassical crystallization process including the generation of amorphous worm-like particles and formation of wheel-like crystallites followed by a−b plane oriented growth of the crystals. The obtained MOR wheel-like assemblies possessed larger surface area and external surface area, displayed better mass transfer properties, and exhibited much better catalytic performance than MOR spheroid-like assemblies and conventional bulk MOR zeolite in dimethyl ether (DME) carbonylation reaction, with two and a half times higher the conversion of DME than the bulk MOR, although these samples had identical Si/Al ratios and acid properties. This work provides a simple route to control the zeolite morphology by alkali metal cations and brings forward an effective strategy to prepare zeolite materials with improved catalytic performance.

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Section: Synthesis Of Mor Zeolitesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Wheel-like Mordenite Nanoassemblies with Shortened Channel Lengths for Improved Catalytic Performance in Dimethyl Ether Carbonylation

Liu,

Wang,

et al. 2023

ACS Appl. Nano Mater.

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“…Diethylbenzene transalkylation can proceed through two main reaction pathways (Scheme ). ,,,− The alkyl transfer mechanism (Scheme a) involves consecutive dealkylation and alkylation steps that proceed through unstable penta-coordinated carbonium ion intermediates. , The first dealkylation of DEB produces an EB molecule and a surface ethoxy group that, in a second step, reacts with benzene and yields EB. However, the ethoxy group can also react with EB or DEB molecules present in the zeolite channels to form undesired overethylated byproducts such as DEB and triethylbenzene (TEB) .…”

Section: Introductionmentioning

confidence: 99%

Design and Synthesis of the Active Site Environment in Zeolite Catalysts for Selectively Manipulating Mechanistic Pathways

Ferri

Paris

et al. 2021

J. Am. Chem. Soc.

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By combining kinetics and theoretical calculations, we show here the benefits of going beyond the concept of static localized and defined active sites on solid catalysts, into a system that globally and dynamically considers the active site located in an environment that involves a scaffold structure particularly suited for a target reaction. We demonstrate that such a system is able to direct the reaction through a preferred mechanism when two of them are competing. This is illustrated here for an industrially relevant reaction, the diethylbenzene–benzene transalkylation. The zeolite catalyst (ITQ-27) optimizes location, density, and environment of acid sites to drive the reaction through the preselected and preferred diaryl-mediated mechanism, instead of the alkyl transfer pathway. This is achieved by minimizing the activation energy of the selected pathway through weak interactions, much in the way that it occurs in enzymatic catalysts. We show that ITQ-27 outperforms previously reported zeolites for the DEB-Bz transalkylation and, more specifically, industrially relevant zeolites such as faujasite, beta, and mordenite.

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“…Heterogeneous catalysis over zeolites play a vital role in organic reactions and contributes significantly to chemical industries Various zeolites, ZSM‐5,‐ Y,‐ and Beta, were studied to access alkylation reactions.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Major Product Distribution Using Experimental‐Theoretical Comparative Studies on Toluene and Ethylbenzene Ethylation over Catalysts Zeolite MCM‐22 and Modified MCM‐22

Thakkar

Bandyopadhyay

2019

ChemistrySelect

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The activity of zeolite MCM-22 and modified MCM-22 catalyst were tested in the vapor phase alkylation of toluene and ethylbenzene by ethanol to investigate the influence of thermodynamic parameters, reaction temperature, and the molar ratio of toluene and ethylbenzene to ethanol. The reactions were evaluated with experimental and theoretical approaches. The catalysts were characterized by XRD, FE-SEM, TGA, N 2 -adsorption, and NH 3 & Py-TPD analyses. The superior catalytic performance of modified MCM-22 was observed in ethylation of ethylbenzene and ethylation of toluene. The catalytic performance indicates that zeolite MCM-22 retained shape selectivity resulting into para-selectivity, while modified MCM-22 possessed more mesopores and increased accessibility to the acid sites thereby increasing conversion of ethylbenzene.

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Alkyl transfer reactions on solid acids. The disproportionation of ethylbenzene and toluene on H-mordenite and HY zeolites

Cited by 8 publications

References 18 publications

Wheel-like Mordenite Nanoassemblies with Shortened Channel Lengths for Improved Catalytic Performance in Dimethyl Ether Carbonylation

Wheel-like Mordenite Nanoassemblies with Shortened Channel Lengths for Improved Catalytic Performance in Dimethyl Ether Carbonylation

Design and Synthesis of the Active Site Environment in Zeolite Catalysts for Selectively Manipulating Mechanistic Pathways

Evaluation of Major Product Distribution Using Experimental‐Theoretical Comparative Studies on Toluene and Ethylbenzene Ethylation over Catalysts Zeolite MCM‐22 and Modified MCM‐22

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