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Catalysis in Zeolites and Zeotypes—Cornerstone of Chemical Industry and Permanent...
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Catalysis in Zeolites and Zeotypes—Cornerstone of Chemical Industry and Permanent Subject of Research

A special issue of Catalysts (ISSN 2073-4344). This special issue belongs to the section "Catalytic Materials".

Deadline for manuscript submissions: closed (30 September 2021) | Viewed by 16516

Special Issue Editor

Prof. Dr. Roman Bulánek

E-Mail Website
Guest Editor
Department of Physical Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentská 573, CZ-532 10 Pardubice, Czech Republic
Interests: thermodynamics of adsorption phenomena in porous materials; coordination and placement of extra-lattice cations in high-silica zeolites; heterogeneously catalysed reactions of gaseous reactants; acido-basic properties of zeolite materials; study of the properties of porous coordination polymers
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Zeolites are microporous crystalline aluminosilicates endowed with amazing properties, which have made them important industrial catalysts, adsorbents, and ion exchangers for more than 50 years. About 250 different structural types of zeolites are known at present. Each of them is unique in terms of the shape and size of the pores, and the dimensionality of the pore systems. These labyrinths of channels and cavities containing extra-framework cations provide a high specific surface area and molecular sieve effect, thanks to which zeolites are intensively used in many industrial processes and the subject of permanent intensive basic research. Every year, new types of zeolites are discovered, new methods for their synthesis are found, and more and more detailed information is obtained about the mechanisms of the crystallization, stability, and flexibility of their frameworks, as well as on the structure and properties of cations coordinated in their channels, thanks to the continuous development of characterization methods and advances in theoretical chemistry.

The purpose of this Special Issue is to provide information on the latest advances in zeolite chemistry, including advances in the synthesis and characterization of zeolites and their application in catalysis and adsorption/separation processes. Topics include but are not limited to conventional 3D zeolites and zeotypes, hierarchical and layered zeolitic materials, as well as zeolite-based composites. We welcome original research papers and short reviews dealing with the study of catalytic activities, the kinetics and mechanisms of chemical processes, the synthesis of new catalytically active materials, the characterization of active centers by advanced characterization methods, the adsorption properties of microporous materials, and applications of molecular sieves and membranes.

Prof. Dr. Roman Bulánek
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Catalysts is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • zeolite
  • zeotype
  • microporous materials
  • solid acid
  • layered and hierarchical zeolites
  • nanozeolites
  • mesoporous zeolites
  • heterogeneous catalysis
  • adsorption
  • separation

Published Papers (7 papers)

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Editorial

Jump to: Research, Review

3 pages, 180 KiB  
Editorial
Catalysis in Zeolites and Zeotypes—Cornerstone of Chemical Industry and Permanent Subject of Research
by Roman Bulánek
Catalysts 2022, 12(1), 53; https://doi.org/10.3390/catal12010053 - 04 Jan 2022
Viewed by 1173
Abstract
Mankind has been aware of zeolites since 1756, when the Swede, Axel Fredrik Cronstedt (1722–1765), observed the strange behavior of a certain natural mineral (probably stellerite with some amounts of stilbite) [...] Full article
(This article belongs to the Special Issue Catalysis in Zeolites and Zeotypes—Cornerstone of Chemical Industry and Permanent Subject of Research)

Research

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10 pages, 1767 KiB  
Article
How Many Molecules Can Fit in a Zeolite Pore? Implications for the Hydrocarbon Pool Mechanism of the Methanol-to-Hydrocarbons Process
by Stewart F. Parker and Aleena J. Kombanal
Catalysts 2021, 11(10), 1204; https://doi.org/10.3390/catal11101204 - 03 Oct 2021
Cited by 3 | Viewed by 2359
Abstract
The methanol-to-hydrocarbons (MTH) process is a very advantageous way to upgrade methanol to more valuable commodity chemicals such as light alkenes and gasoline. There is general agreement that, at steady state, the process operates via a dual cycle “hydrocarbon pool” mechanism. This mechanism [...] Read more.
The methanol-to-hydrocarbons (MTH) process is a very advantageous way to upgrade methanol to more valuable commodity chemicals such as light alkenes and gasoline. There is general agreement that, at steady state, the process operates via a dual cycle “hydrocarbon pool” mechanism. This mechanism defines a minimum number of reactants, intermediates, and products that must be present for the reaction to occur. In this paper, we calculate (by three independent methods) the volume required for a range of compounds that must be present in a working catalyst. These are compared to the available volume in a range of zeolites that have been used, or tested, for MTH. We show that this straightforward comparison provides a means to rationalize the product slate and the deactivation pathways in zeotype materials used for the MTH reaction. Full article
(This article belongs to the Special Issue Catalysis in Zeolites and Zeotypes—Cornerstone of Chemical Industry and Permanent Subject of Research)
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17 pages, 3393 KiB  
Article
Pore Blocking by Phenolates as Deactivation Path during the Cracking of 4-Propylphenol over ZSM-5
by Michael J. Stellato, Giada Innocenti, Andreas S. Bommarius and Carsten Sievers
Catalysts 2021, 11(6), 721; https://doi.org/10.3390/catal11060721 - 10 Jun 2021
Cited by 8 | Viewed by 2366
Abstract
Cracking of propyl side chains from 4-propylphenol, a model compound for lignin monomers, is studied for a commercial ZSM-5 zeolite catalyst. The decline of 4-propylphenol conversion with time on stream can be delayed by co-feeding water. FTIR spectroscopy shows the formation of chemisorbed [...] Read more.
Cracking of propyl side chains from 4-propylphenol, a model compound for lignin monomers, is studied for a commercial ZSM-5 zeolite catalyst. The decline of 4-propylphenol conversion with time on stream can be delayed by co-feeding water. FTIR spectroscopy shows the formation of chemisorbed phenolates during reactions and significant amounts of phenolics are detected by GC-MS of the extract from the spent catalysts. Thus, chemisorbed phenolates are identified as the main reason for deactivation in the absence of water. Regardless of the amount of co-fed water, substituted monoaromatics and polyaromatic species are formed. Comprehensive characterization of the spent catalysts including Raman and solid-state 27Al NMR spectroscopy, and thermogravimetric analysis points to a combination of deactivation processes. First, phenolates bind to Lewis acid sites within the zeolite framework and hinder diffusion unless they are hydrolyzed by water. In addition, light olefins created during the cracking process react to form a polyaromatic coke that deactivates the catalyst more permanently. Full article
(This article belongs to the Special Issue Catalysis in Zeolites and Zeotypes—Cornerstone of Chemical Industry and Permanent Subject of Research)
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14 pages, 2451 KiB  
Article
Physico-Chemical Changes in the KCl-MgCl2/La-FAU Composite Catalyst Induced by Oxidative Dehydrogenation of Ethane
by Mehran Sajad, Roman Bulánek and Stanislav Šlang
Catalysts 2021, 11(3), 392; https://doi.org/10.3390/catal11030392 - 19 Mar 2021
Cited by 1 | Viewed by 2208
Abstract
In this research, a binary eutectic composition of KCl and MgCl2 supported over lanthanum exchanged FAU (faujasite) zeolite has been investigated for the oxidative dehydrogenation (ODH) of ethane. The catalyst was prepared by the thermal treatment of La-FAU with a mechanical mixture [...] Read more.
In this research, a binary eutectic composition of KCl and MgCl2 supported over lanthanum exchanged FAU (faujasite) zeolite has been investigated for the oxidative dehydrogenation (ODH) of ethane. The catalyst was prepared by the thermal treatment of La-FAU with a mechanical mixture of alkali chlorides under a flow of helium at 500 °C. The eutectic mixture of alkali chlorides formed at this temperature and a molten layer were spread over the support. Synthesized fresh and spent catalysts were characterized to obtain information about changes in crystallinity, textural properties, phase content, chemical composition, and morphology of the catalyst over the reaction time. The initial conversion of ethane was 80% with ethene as the main product (65% yield). The catalyst deactivation has been demonstrated over time on the stream (TOS). The characterization methods confirmed that the chlorine was being removed from the catalyst. The side products detected by mass spectroscopy, including chlorinated hydrocarbons, have been found as a key pathway of chlorine removal from the catalyst. The exchange of chlorine for oxygen in the catalyst led to a significant decrease in the activity and production of higher hydrocarbons and their oxygenates as side products of the ODH reaction. Full article
(This article belongs to the Special Issue Catalysis in Zeolites and Zeotypes—Cornerstone of Chemical Industry and Permanent Subject of Research)
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12 pages, 1920 KiB  
Article
Acidity as Descriptor for Methanol Desorption in B-, Ga- and Ti-MFI Zeotypes
by Simone Creci, Anna Martinelli, Szilvia Vavra, Per-Anders Carlsson and Magnus Skoglundh
Catalysts 2021, 11(1), 97; https://doi.org/10.3390/catal11010097 - 12 Jan 2021
Cited by 5 | Viewed by 1690
Abstract
The isomorphous substitution of Si with metals other than Al in zeotype frameworks allows for tuning the acidity of the zeotype and, therefore, to tailor the catalyst’s properties as a function of the desired catalytic reaction. In this study, B, Ga, and Ti [...] Read more.
The isomorphous substitution of Si with metals other than Al in zeotype frameworks allows for tuning the acidity of the zeotype and, therefore, to tailor the catalyst’s properties as a function of the desired catalytic reaction. In this study, B, Ga, and Ti are incorporated in the MFI framework of silicalite samples and the following series of increasing acidity is observed: Ti-silicalite < B-silicalite < Ga-silicalite. It is also observed that the lower the acidity of the sample, the easier the methanol desorption from the zeotype surface. In the target reaction, namely the direct conversion of methane to methanol, methanol extraction is affected by the zeotype acidity. Therefore, the results shown in this study contribute to a more enriched knowledge of this reaction. Full article
(This article belongs to the Special Issue Catalysis in Zeolites and Zeotypes—Cornerstone of Chemical Industry and Permanent Subject of Research)
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Review

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16 pages, 2501 KiB  
Review
Recent Progress in Synthesis and Application of Nanosized and Hierarchical Mordenite—A Short Review
by Yuri Kalvachev, Totka Todorova and Cyril Popov
Catalysts 2021, 11(3), 308; https://doi.org/10.3390/catal11030308 - 26 Feb 2021
Cited by 21 | Viewed by 3116
Abstract
Zeolites with their unique properties find applications in various fields, including medicine, agronomy, ecology, production of detergents and drying agents, and in a number of industrial processes. Among zeolites, mordenite is particularly widespread because of its high silica/alumina ratio, which allows it to [...] Read more.
Zeolites with their unique properties find applications in various fields, including medicine, agronomy, ecology, production of detergents and drying agents, and in a number of industrial processes. Among zeolites, mordenite is particularly widespread because of its high silica/alumina ratio, which allows it to resist exposure to high temperatures and to acidic gases and liquids. Mordenite is commercially available as a natural mineral and as a synthesized material. This zeolite is mostly used in its synthetic form as an acid catalyst in the petrochemical industry for the isomerization of alkanes and aromatics. In this review, we consider the scientific literature on the structure, synthesis, and two main types of modifications that solve the diffusion difficulties during catalytic processes. The first type of modifications is related to a reduction of the size of the mordenite crystals obtained to submicron or nanometric range, whereas the second ones aim to obtain hierarchical mordenite samples by appropriate post-synthetic treatments. Both types of modifications find many other applications besides solving diffusion constraints in catalytic processes. Attempts to fine-tune and control the particle size in the first type of modifications or the pore size in the second ones by adjusting various parameters during the synthesis are described. Full article
(This article belongs to the Special Issue Catalysis in Zeolites and Zeotypes—Cornerstone of Chemical Industry and Permanent Subject of Research)
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25 pages, 5070 KiB  
Review
Milling Activation for the Solvent-Free Synthesis of Zeolites. A Practical Guide
by Agnieszka Kornas, Joanna E. Olszówka, Petr Klein and Veronika Pashkova
Catalysts 2021, 11(2), 246; https://doi.org/10.3390/catal11020246 - 12 Feb 2021
Cited by 7 | Viewed by 2615
Abstract
The paramount challenge of current chemical technology, including catalysis, is meeting the ecological sustainability requirements. The feasible production of zeolites is crucial because they constitute the principal group of heterogeneous catalysts. However, current zeolite manufacturing via hydrothermal synthesis is connected with considerable consumption [...] Read more.
The paramount challenge of current chemical technology, including catalysis, is meeting the ecological sustainability requirements. The feasible production of zeolites is crucial because they constitute the principal group of heterogeneous catalysts. However, current zeolite manufacturing via hydrothermal synthesis is connected with considerable consumption of water resources, generation of wastewater, and significant equipment costs. Solvent-free strategies have attracted great attention as high-yielding methods for sustainable synthesis, particularly beneficial in terms of water consumption minimization and an outstanding increase in production due to the efficient use of synthesis space capacity. So far, the solvent-free preparation of numerous zeolite materials has been performed with the preceding grinding of reagents in a mortar. The proposed article describes recent advances in the application of automatized milling instead of manual work. Pretreatment automatization makes the entire process well-controlled, less sensitive to human factors, and is significantly more relevant to industrial scale-up. Moreover, the automatized milling activation unlocks opportunities for solvent-free synthesis from a broader range of common reagents, where the manual treatment is not efficient. Possibilities and limitations of the milling methods are discussed on the basis of a comprehensive analysis of parameter optimization, activation mechanisms, and applicability of common reagents used for zeolite production. Full article
(This article belongs to the Special Issue Catalysis in Zeolites and Zeotypes—Cornerstone of Chemical Industry and Permanent Subject of Research)
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