Synthesis of a hierarchically macro-/mesoporous zeolite based on a micro-emulsion mechanism

Li, Hua; Jin, Junjiang; Wu, Wei; Chen, Chongcheng; Li, Liang; Yong-shen, LI; Zhao, Wenru; Gu, Jinlou; Chen, Guorong; Shi, Jianlin

doi:10.1039/c1jm14249f

Cited by 39 publications

(28 citation statements)

References 44 publications

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“…The main principle behind the emulsion approaches is a phase-separation process during the zeolite formation: A mixture consisting of an organic and an aqueous phase undergoes a phase-separation under the applied synthesis conditions in such a way that the zeolite mixture (aqueous phase) and the organic fraction (future pore/ void) form a stable, biphasic (and potentially bicontinuous) emulsion. 62,63,80 To achieve this objective, in most cases surfactants and co-surfactants are necessary to prevent the microor mini-emulsion from complete phase-separation. 81 Lee and Shantz 62 used polyoxyethylenenonylphenyl ether as surfactant and butanol as co-surfactant to emulsify the aqueous droplets of a silicalite-1 synthesis mixture (tetraethoxysilane (TEOS)/ TPAOH/water) in heptane serving as the organic phase.…”

Section: Soft Templating Methodsmentioning

confidence: 99%

Hierarchy concepts: classification and preparation strategies for zeolite containing materials with hierarchical porosity

et al. 2016

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'Hierarchy' is a property which can be attributed to a manifold of different immaterial systems, such as ideas, items and organisations or material ones like biological systems within living organisms or artificial, man-made constructions. The property 'hierarchy' is mainly characterised by a certain ordering of individual elements relative to each other, often in combination with a certain degree of branching.Especially mass-flow related systems in the natural environment feature special hierarchically branched patterns. This review is a survey into the world of hierarchical systems with special focus on hierarchically porous zeolite materials. A classification of hierarchical porosity is proposed based on the flow distribution pattern within the respective pore systems. In addition, this review might serve as a toolbox providing several synthetic and post-synthetic strategies to prepare zeolitic or zeolite containing material with tailored hierarchical porosity. Very often, such strategies with their underlying principles were developed for improving the performance of the final materials in different technical applications like adsorptive or catalytic processes. In the present review, besides on the hierarchically porous allzeolite material, special focus is laid on the preparation of zeolitic composite materials with hierarchical porosity capable to face the demands of industrial application.

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Section: Soft Templating Methodsmentioning

confidence: 99%

Hierarchy concepts: classification and preparation strategies for zeolite containing materials with hierarchical porosity

et al. 2016

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“…Recently, Ryoo and co‐workers fabricated truly ordered mesoporous mordenite framework inverted (MFI) by using linear gemini‐type templates consisting of several bridged ammonium cations terminated by long alkyl chains 13j. To avoid the phase‐separation process between the mesoporogen and the crystalline wall, a number of attempts have been made, including using cationic polymer or surfactant template,12c, f, 13a,b, k silane‐functionalized surfactant or polymer,12b, 13e steam‐assisted crystallization,11a, f, 12g, 13i and dense mesoporogen/silica composite hydrothermal crystallization 11b,c. 12d However, the above syntheses employed the elaborately built “hard” porogens including carbon nanotubes, carbon particles and pre‐organized carbon scaffolds, or soft templates, such as specially designed dual‐functional and environmental‐unfriendly surfactants, which involved either multi‐step procedures or less cost‐effective templates in the synthesis.…”

Section: Introductionmentioning

confidence: 99%

A Simple Route to Synthesize Mesoporous ZSM‐5 Templated by Ammonium‐Modified Chitosan

Jin

Zhang

et al. 2012

Chemistry A European J

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Uniform mesoporous zeolite ZSM-5 crystals have been successfully fabricated through a simple hydrothermal synthetic method by utilizing ammonium-modified chitosan and tetrapropylammonium hydroxide (TPAOH) as the meso- and microscale template, respectively. It was revealed that mesopores with diameters of 5-20 nm coexisted with microporous network within mesoporous ZSM-5 crystals. Ammonium-modified chitosan was demonstrated to serve as a mesoporogen, self-assembling with the zeolite precursor through strong static interactions. As expected, the prepared mesoporous ZSM-5 exhibited greatly enhanced catalytic activities compared with conventional ZSM-5 and Al-MCM-41 in reactions involving bulky molecules, such as the Claisen-Schmidt condensation of 2-hydroxyacetophenone with benzaldehyde and the esterification reaction of dodecanoic acid and 2-ethylhexanol.

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“…Templating with preshaped macroscopic structured precursors: Different macroscopic structured precursors such as silica monoliths, preshaped amorphous alumosilicates, [ 41 ] biological scaffolds, [ 32 ] polymers, [ 42 ] carbon structures, [ 43 ] ion exchange beads, [ 44 ] emulsions, [ 45 ] spray dried beads, [ 46 ] extrudates, [ 47 ] porous glass, [ 48 ] silica gel, [ 49 ] or even 3D printed precursors [ 50 ] have been successfully completely zeolitized. From this long list, these precursors can be classified as natural occurring and synthetic.…”

Section: Preparation Methods For Hierarchically Structured Zeolites mentioning

confidence: 99%

Preparation and Potential Catalytic Applications of Hierarchically Structured Zeolites with Macropores

Weissenberger

Machoke

Reiprich

et al. 2021

Adv Materials Inter

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Hierarchically structured zeolites can mitigate problems arising from the slow transport in the micropores, such as diffusion limitations. Hence, a manifold of different preparation methods for hierarchical zeolites have been developed over the years and the corresponding zeolites showed superior performance due to enhanced mass transport caused by higher diffusivities in the additional pore system and reduced diffusion path length in the micropores. The dimensions of the additional secondary “transport” pores in these materials is a major factor affecting their diffusion properties and consequently their catalytic performance. Interestingly almost all reports focus on the generation of additional mesopores and study of catalytic performance of mesoporous zeolites. Larger macropores with pore diameters of more than 50 nm, however, have some intrinsic advantages over mesopores that make them very attractive for catalytic applications. In the last years, methods for the preparation of zeolites and zeolite composites with additional macropores have been developed. These developments have brought about a novel and promising class of hierarchically structured materials; zeolites with macropores. This review gives an overview about different preparation routes for zeolites with inter or intra crystalline macropores as well as zeolite composites with macropores and summarizes the first studies regarding catalytic their performance.

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Synthesis of a hierarchically macro-/mesoporous zeolite based on a micro-emulsion mechanism

Cited by 39 publications

References 44 publications

Hierarchy concepts: classification and preparation strategies for zeolite containing materials with hierarchical porosity

Hierarchy concepts: classification and preparation strategies for zeolite containing materials with hierarchical porosity

A Simple Route to Synthesize Mesoporous ZSM‐5 Templated by Ammonium‐Modified Chitosan

Preparation and Potential Catalytic Applications of Hierarchically Structured Zeolites with Macropores

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