Dimethyl ether carbonylation over nanosheet-assembled hierarchical mordenite

Wang, Xiaosheng; Li, Ranjia; Chen, Yu; Zhang, Liya; Chen, Xu; Zhou, Hongjun

doi:10.1016/j.micromeso.2018.07.048

Cited by 29 publications

(21 citation statements)

References 32 publications

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“…Accordingly, nanosheet MOR material exhibits higher activity, xylene selectivity, and longer catalyst lifetime in the toluene disproportionation reaction [242]. The PEG has acted as a mesopore generation agent in the formation of a set of hierarchical MOR catalysts with enhanced crystallinity and a higher quantity of strong acid sites in comparison to the reference zeolite obtained without PEG [243]. The stability and activity of the PEG-MOR-type materials employed as catalysts for DME carbonylation is greatly enhanced with respect to the conventional MOR-type sample.…”

Section: T3 T4mentioning

confidence: 99%

Analysis and control of acid sites in zeolites

Palčić

Valtchev

2020

Applied Catalysis A: General

118

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The exceptional catalytic performance of zeolites is due to the presence of active sites in a shape-selective environment, i.e., in micropores with molecular dimensions. The present review provides a comprehensive analysis of active sites in zeolite frameworks. It is focused on the active sites generated by the Al incorporation in the framework. The inclusion of other heteroatoms in the zeolite framework is also addressed. After the introduction of zeolite-type materials and a discussion of the structure-properties relationship in zeolites the central part of the review is devoted to i) the analytical methods and their complementarity for the evaluation of the number, strength, and position of active sites and ii) the in situ and post-synthesis methods of acid sites assessment and control. The data presented herein provide guidelines for making zeolite materials by design in terms of acidity.

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Section: T3 T4mentioning

confidence: 99%

Analysis and control of acid sites in zeolites

Palčić

Valtchev

2020

Applied Catalysis A: General

118

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“…Generally, organosilanes and mono‐ or multi‐quaternary ammonium salts have been employed to introduce mesoporosity in MOR zeolite. Nearly all of the described recipes involve the addition of a mesoporogen to a synthesis mixture which contains seeds, conventional SDAs, or require complex cationic surfactants with two or more ammonium ions . There are only few reports that claim the formation of hierarchical MOR zeolite with a mono‐quaternary ammonium surfactant or aniline as a single SDA .…”

Section: Introductionmentioning

confidence: 99%

Mordenite Nanorods Prepared by an Inexpensive Pyrrolidine‐based Mesoporogen for Alkane Hydroisomerization

et al. 2019

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We report the synthesis of hierarchical mordenite zeolite nanorods in one step using inexpensive mono‐quaternary ammonium N‐cetyl‐N‐methylpyrrolidinium (C16NMP) as mesoporogen to the synthesis gel. The presence of a small amount of C16NMP results in the formation of 0.6–1 μm rods‐like crystals oriented along the c‐axis with a high mesoporous volume (0.12 cm3 g−1) and external surface area (∼90 m2 g−1) compared to bulk mordenite. Acidity characterization shows that the presence of C16NMP during mordenite formation leads to a redistribution of aluminum in the zeolite framework: the amount of Brønsted acid sites in the side‐pockets (8MR channels) is increased at the expense of those in the 12MR main channels. As these latter acid sites are the ones involved in the conversion of alkene intermediates in bifunctional hydroconversion of alkanes, an optimized hierarchical mordenite prepared with C16NMP displays a more ideal hydrocracking selectivity than bulk MOR prepared solely with sodium.

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“…[276] Next to nanorods, nanosheets can be synthesized as well. This was done by Wang et al [277] and Liu et al [278] who both employed PEG as template in the hydrothermal synthesis, however, Liu et al also used CTAB as an additional template. It was shown that the use of PEG dramatically increased the crystallinity compared to reference mordenites that were synthesized without the addition of PEG.…”

Section: Nanozeolites and Their Assemblymentioning

confidence: 99%

“…This was done by Wang et al. [ 277 ] and Liu et al. [ 278 ] who both employed PEG as template in the hydrothermal synthesis, however, Liu et al.…”

Section: Synthesis Of Hierarchical 12‐mr Zeolitesmentioning

confidence: 99%

“…An increase in molecular weight resulted in an increased stability of the catalytic activity in the carbonylation of DME, which was explained by an increase in specific surface area (from 487.1 to 567.4 m 2 g −1 ), total pore volume (from 0.201 to 0.218 cm 3 g −1 ), and acid site strength compared to a mordenite that was synthesized without addition of PEG. [ 277 ] Next to relatively simple templates such as PEG and CTAB, more complex mesoporogens have been recently investigated, namely, gemini‐type amphiphilic surfactants. Such templates were employed by Lu et al., who showed that the benzyl diquaternary ammonium cations structurally directed the crystallization toward the MOR topology, whereas a long hydrophobic hexadecyl tail prevented crystal growth along the b ‐axis ( Figure ).…”

Section: Synthesis Of Hierarchical 12‐mr Zeolitesmentioning

confidence: 99%

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State of the Art and Perspectives of Hierarchical Zeolites: Practical Overview of Synthesis Methods and Use in Catalysis

et al. 2020

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Zeolites are highly crystalline aluminosilicates with welldefined pores that are constructed of SiO 2 and AlO 4 tetrahedra. These tetrahedra can be linked together in different unique ways to form various materials with a specific topology. [1] According to the International Zeolite Association (IZA), more than 250 different topologies, which are all assigned with a three-letter code, have been identified. [2] The micropores in zeolites are typically constructed from 8, 10, or 12 tetrahedral atoms

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Dimethyl ether carbonylation over nanosheet-assembled hierarchical mordenite

Cited by 29 publications

References 32 publications

Analysis and control of acid sites in zeolites

Analysis and control of acid sites in zeolites

Mordenite Nanorods Prepared by an Inexpensive Pyrrolidine‐based Mesoporogen for Alkane Hydroisomerization

State of the Art and Perspectives of Hierarchical Zeolites: Practical Overview of Synthesis Methods and Use in Catalysis

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