1
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Ezenwa S, Gounder R. Advances and challenges in designing active site environments in zeolites for Brønsted acid catalysis. Chem Commun (Camb) 2024. [PMID: 39344420 DOI: 10.1039/d4cc04728a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/01/2024]
Abstract
Zeolites contain proton active sites in diverse void environments that stabilize the reactive intermediates and transition states formed in converting hydrocarbons and oxygenates to chemicals and energy carriers. The catalytic diversity that exists among active sites in voids of varying sizes and shapes, even within a given zeolite topology, has motivated research efforts to position and quantify active sites within distinct voids (synthesis-structure) and to link active site environment to catalytic behavior (structure-reactivity). This Feature Article describes advances and challenges in controlling the position of framework Al centers and associated protons within distinct voids during zeolite synthesis or post-synthetic modification, in identifying and quantifying distinct active site environments using characterization techniques, and in determining the influence of active site environments on catalysis. During zeolite synthesis, organic structure directing agents (SDAs) influence Al substitution at distinct lattice positions via intermolecular interactions (e.g., electrostatics, hydrogen bonding) that depend on the size, structure, and charge distribution of organic SDAs and their mobility when confined within zeolitic voids. Complementary post-synthetic strategies to alter intrapore active site distributions include the selective removal of protons by differently-sized titrants or unreactive organic residues and the selective exchange of framework heteroatoms of different reactivities, but remain limited to certain zeolite frameworks. The ability to identify and quantify active sites within distinct intrapore environments depends on the resolution with which a given characterization technique can distinguish Al T-site positions or proton environments in a given zeolite framework. For proton sites in external unconfined environments, various (post-)synthetic strategies exist to control their amounts, with quantitative methods to distinguish them from internal sites that largely depend on using stoichiometric or catalytic probes that only interact with external sites. Protons in different environments influence reactivity by preferentially stabilizing larger transition states over smaller precursor states and influence selectivity by preferentially stabilizing or destabilizing competing transition states of varying sizes that share a common precursor state. We highlight opportunities to address challenges encountered in the design of active site environments in zeolites by closely integrating precise (post-)synthetic methods, validated characterization techniques, well-defined kinetic probes, and properly calibrated theoretical models. Further advances in understanding the molecular details that underlie synthesis-structure-reactivity relationships for active site environments in zeolite catalysis can accelerate the predictive design of tailored zeolites for desired catalytic transformations.
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Affiliation(s)
- Sopuruchukwu Ezenwa
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN, 47907, USA.
| | - Rajamani Gounder
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN, 47907, USA.
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2
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Ezenwa S, Montalvo-Castro H, Hoffman AJ, Locht H, Attebery J, Jan DY, Schmithorst M, Chmelka B, Hibbitts D, Gounder R. Synthetic Placement of Active Sites in MFI Zeolites for Selective Toluene Methylation to para-Xylene. J Am Chem Soc 2024; 146:10666-10678. [PMID: 38573868 DOI: 10.1021/jacs.4c00373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2024]
Abstract
Brønsted acidic zeolites are ubiquitous catalysts in fuel and chemical production. Broadening the catalytic diversity of a given zeolite requires strategies to manipulate the acid site placement at framework positions within distinct microporous locations. Here, we combine experiment and theory to elucidate how intermolecular interactions between organic structure-directing agents (OSDAs) and framework Al centers influence the placement of H+ sites in distinct void environments of MFI zeolites and demonstrate the catalytic consequences of active site location on kinetically controlled (403 K) toluene methylation to xylene regioisomers. Kinetic measurements, interpreted using mechanism-derived rate expressions and transition state theory, alongside density functional theory (DFT) calculations show that larger intersection environments similarly stabilize all three xylene isomer transition states without altering well-established aromatic substitution patterns (ortho/para/meta ∼ 60%:30%:10%), while smaller channel environments preferentially destabilize transition states that form bulkier ortho- and meta-isomers, thereby resulting in high intrinsic para-xylene selectivity (∼80%). DFT calculations reveal that the flexibility of nonconventional OSDAs (e.g., 1,4-diazabicyclo[2.2.2]octane) to reorient within MFI intersections and their ability to hydrogen-bond to form protonated complexes favor the placement of Al in smaller channel environments compared to conventional quaternary OSDAs (e.g., tetra-n-propylammonium). These molecular-level insights establish a mechanistic link between OSDA structure, active site placement, and transition state stability in MFI zeolites and provide active site design strategies that are orthogonal to crystallite design approaches harnessing complex reaction-diffusion phenomena to enhance regioisomer selectivity in the industrial production of valuable polymer precursors.
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Affiliation(s)
- Sopuruchukwu Ezenwa
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Hansel Montalvo-Castro
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32608, United States
| | - Alexander J Hoffman
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32608, United States
| | - Huston Locht
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32608, United States
| | - Jordan Attebery
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32608, United States
| | - Deng-Yang Jan
- Honeywell UOP, Des Plaines, Illinois 60017, United States
| | - Michael Schmithorst
- Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Bradley Chmelka
- Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - David Hibbitts
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32608, United States
| | - Rajamani Gounder
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
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3
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Gomes GJ, Zalazar MF, Padilha JC, Costa MB, Bazzi CL, Arroyo PA. Unveiling the mechanisms of carboxylic acid esterification on acid zeolites for biomass-to-energy: A review of the catalytic process through experimental and computational studies. CHEMOSPHERE 2024; 349:140879. [PMID: 38061565 DOI: 10.1016/j.chemosphere.2023.140879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 11/19/2023] [Accepted: 12/01/2023] [Indexed: 01/10/2024]
Abstract
In recent years, there has been significant interest from industrial and academic areas in the esterification of carboxylic acids catalyzed by acidic zeolites, as it represents a sustainable and economically viable approach to producing a wide range of high-value-added products. However, there is a lack of comprehensive reviews that address the intricate reaction mechanisms occurring at the catalyst interface at both the experimental and atomistic levels. Therefore, in this review, we provide an overview of the esterification reaction on acidic zeolites based on experimental and theoretical studies. The combination of infrared spectroscopy with atomistic calculations and experimental strategies using modulation excitation spectroscopy techniques combined with phase-sensitive detection is presented as an approach to detecting short-lived intermediates at the interface of zeolitic frameworks under realistic reaction conditions. To achieve this goal, this review has been divided into four sections: The first is a brief introduction highlighting the distinctive features of this review. The second addresses questions about the topology and activity of different zeolitic systems, since these properties are closely correlated in the esterification process. The third section deals with the mechanisms proposed in the literature. The fourth section presents advances in IR techniques and theoretical calculations that can be applied to gain new insights into reaction mechanisms. Finally, this review concludes with a subtle approach, highlighting the main aspects and perspectives of combining experimental and theoretical techniques to elucidate different reaction mechanisms in zeolitic systems.
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Affiliation(s)
- Glaucio José Gomes
- Laboratorio de Estructura Molecular y Propiedades (LEMyP), Instituto de Química Básica y Aplicada Del Nordeste Argentino, (IQUIBA-NEA), Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional Del Nordeste (CONICET-UNNE), Avenida Libertad 5460, 3400, Corrientes, Argentina; Laboratório de Catálise Heterogênea e Biodiesel (LCHBio), Universidade Estadual de Maringá (UEM), Avenida Colombo, 5790, (87020-900), Maringá, Paraná, Brazil; Programa de Pós-Graduação Interdisciplinar Em Energia e Sustentabilidade, Universidade Federal da Integração Latino-Americana (UNILA), Avenida Presidente Tancredo Neves, 3838, (85870-650), Foz Do Iguaçu, Paraná, Brazil.
| | - María Fernanda Zalazar
- Laboratorio de Estructura Molecular y Propiedades (LEMyP), Instituto de Química Básica y Aplicada Del Nordeste Argentino, (IQUIBA-NEA), Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional Del Nordeste (CONICET-UNNE), Avenida Libertad 5460, 3400, Corrientes, Argentina.
| | - Janine Carvalho Padilha
- Programa de Pós-Graduação Interdisciplinar Em Energia e Sustentabilidade, Universidade Federal da Integração Latino-Americana (UNILA), Avenida Presidente Tancredo Neves, 3838, (85870-650), Foz Do Iguaçu, Paraná, Brazil
| | - Michelle Budke Costa
- Universidade Tecnológica Federal Do Paraná (UTFPR), Avenida Brasil 4232, (85884-000), Medianeira, Brazil
| | - Claudio Leones Bazzi
- Universidade Tecnológica Federal Do Paraná (UTFPR), Avenida Brasil 4232, (85884-000), Medianeira, Brazil
| | - Pedro Augusto Arroyo
- Laboratório de Catálise Heterogênea e Biodiesel (LCHBio), Universidade Estadual de Maringá (UEM), Avenida Colombo, 5790, (87020-900), Maringá, Paraná, Brazil
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4
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Wang Y, Tong C, Liu Q, Han R, Liu C. Intergrowth Zeolites, Synthesis, Characterization, and Catalysis. Chem Rev 2023; 123:11664-11721. [PMID: 37707958 DOI: 10.1021/acs.chemrev.3c00373] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/16/2023]
Abstract
Microporous zeolites that can act as heterogeneous catalysts have continued to attract a great deal of academic and industrial interest, but current progress in their synthesis and application is restricted to single-phase zeolites, severely underestimating the potential of intergrowth frameworks. Compared with single-phase zeolites, intergrowth zeolites possess unique properties, such as different diffusion pathways and molecular confinement, or special crystalline pore environments for binding metal active sites. This review first focuses on the structural features and synthetic details of all the intergrowth zeolites, especially providing some insightful discussion of several potential frameworks. Subsequently, characterization methods for intergrowth zeolites are introduced, and highlighting fundamental features of these crystals. Then, the applications of intergrowth zeolites in several of the most active areas of catalysis are presented, including selective catalytic reduction of NOx by ammonia (NH3-SCR), methanol to olefins (MTO), petrochemicals and refining, fine chemicals production, and biomass conversion on Beta, and the relationship between structure and catalytic activity was profiled from the perspective of intergrowth grain boundary structure. Finally, the synthesis, characterization, and catalysis of intergrowth zeolites are summarized in a comprehensive discussion, and a brief outlook on the current challenges and future directions of intergrowth zeolites is indicated.
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Affiliation(s)
- Yanhua Wang
- Tianjin Key Laboratory of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China
- State Key Laboratory of Engines, Tianjin University, Tianjin 300072, China
| | - Chengzheng Tong
- Tianjin Key Laboratory of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China
- State Key Laboratory of Engines, Tianjin University, Tianjin 300072, China
| | - Qingling Liu
- Tianjin Key Laboratory of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China
- State Key Laboratory of Engines, Tianjin University, Tianjin 300072, China
| | - Rui Han
- Tianjin Key Laboratory of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China
- State Key Laboratory of Engines, Tianjin University, Tianjin 300072, China
| | - Caixia Liu
- Tianjin Key Laboratory of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China
- State Key Laboratory of Engines, Tianjin University, Tianjin 300072, China
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5
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Schmithorst MB, Prasad S, Moini A, Chmelka BF. Direct Detection of Paired Aluminum Heteroatoms in Chabazite Zeolite Catalysts and Their Significance for Methanol Dehydration Reactivity. J Am Chem Soc 2023; 145:18215-18220. [PMID: 37552830 DOI: 10.1021/jacs.3c05708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2023]
Abstract
The distributions of heteroatoms within zeolite frameworks have important influences on the locations of exchangeable cations, which account for the diverse adsorption and reaction properties of zeolite catalysts. In particular for aluminosilicate zeolites, paired configurations of aluminum atoms separated by one or two tetrahedrally coordinated silicon atoms are important for charge-balancing pairs of H+ cations, which are active for methanol dehydration, or divalent metal cations, such as Cu2+, which selectively catalyze the reduction of NOx, both technologically important reactions. Such paired heteroatom configurations, however, are challenging to detect and probe, due to the typically nonstoichiometric compositions and nonperiodic distributions of aluminum atoms within aluminosilicate zeolite frameworks. Nevertheless, distinct configurations of paired framework aluminum atoms are unambiguously detected and resolved in solid-state 2D 27Al-29Si and 29Si-29Si NMR spectra, which are sensitive to the local environments of covalently bonded 27Al-O-29Si and 29Si-O-29Si moieties, respectively. Specifically, two H+-chabazite zeolites with the same bulk framework aluminum contents are shown to have different types and populations of closely paired aluminum species, which correlate with higher activity for methanol dehydration. The methodologies and insights are expected to be broadly applicable to analyses of heteroatom sites, their distributions, and adsorption and reaction properties in other zeolite framework types.
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Affiliation(s)
- Michael B Schmithorst
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
| | | | - Ahmad Moini
- BASF Corporation, Iselin, New Jersey 08830, United States
| | - Bradley F Chmelka
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
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6
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Li J, Gao M, Yan W, Yu J. Regulation of the Si/Al ratios and Al distributions of zeolites and their impact on properties. Chem Sci 2023; 14:1935-1959. [PMID: 36845940 PMCID: PMC9945477 DOI: 10.1039/d2sc06010h] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 12/27/2022] [Indexed: 12/29/2022] Open
Abstract
Zeolites are typically a class of crystalline microporous aluminosilicates that are constructed by SiO4 and AlO4 tetrahedra. Because of their unique porous structures, strong Brönsted acidity, molecular-level shape selectivity, exchangeable cations, and high thermal/hydrothermal stability, zeolites are widely used as catalysts, adsorbents, and ion-exchangers in industry. The activity, selectivity, and stability/durability of zeolites in applications are closely related to their Si/Al ratios and Al distributions in the framework. In this review, we discussed the basic principles and the state-of-the-art methodologies for regulating the Si/Al ratios and Al distributions of zeolites, including seed-assisted recipe modification, interzeolite transformation, fluoride media, and usage of organic structure-directing agents (OSDAs), etc. The conventional and newly developed characterization methods for determining the Si/Al ratios and Al distributions were summarized, which include X-ray fluorescence spectroscopy (XRF), solid state 29Si/27Al magic-angle-spinning nuclear magnetic resonance spectroscopy (29Si/27Al MAS NMR), Fourier-transform infrared spectroscopy (FT-IR), etc. The impact of Si/Al ratios and Al distributions on the catalysis, adsorption/separation, and ion-exchange performance of zeolites were subsequently demonstrated. Finally, we presented a perspective on the precise control of the Si/Al ratios and Al distributions of zeolites and the corresponding challenges.
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Affiliation(s)
- Jialiang Li
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University 2699 Qianjin Street Changchun 130012 China
| | - Mingkun Gao
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University 2699 Qianjin Street Changchun 130012 China
| | - Wenfu Yan
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University 2699 Qianjin Street Changchun 130012 China
| | - Jihong Yu
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University 2699 Qianjin Street Changchun 130012 China
- International Center of Future Science, Jilin University 2699 Qianjin Street Changchun 130012 China
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7
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Pham TN, Nguyen V, Nguyen-Phu H, Wang B, Crossley S. Influence of Brønsted Acid Site Proximity on Alkane Cracking in MFI Zeolites. ACS Catal 2023. [DOI: 10.1021/acscatal.2c05291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Tram N. Pham
- School of Chemical, Biological and Materials Engineering, University of Oklahoma, Norman, Oklahoma73019, United States
| | - Vy Nguyen
- School of Chemical, Biological and Materials Engineering, University of Oklahoma, Norman, Oklahoma73019, United States
| | - Huy Nguyen-Phu
- School of Chemical, Biological and Materials Engineering, University of Oklahoma, Norman, Oklahoma73019, United States
| | - Bin Wang
- School of Chemical, Biological and Materials Engineering, University of Oklahoma, Norman, Oklahoma73019, United States
| | - Steven Crossley
- School of Chemical, Biological and Materials Engineering, University of Oklahoma, Norman, Oklahoma73019, United States
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8
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Plessow PN, Studt F. Cooperative Effects of Active Sites in the MTO Process: A Computational Study of the Aromatic Cycle in H-SSZ-13. ACS Catal 2022. [DOI: 10.1021/acscatal.2c04694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Philipp N. Plessow
- Institute of Catalysis Research and Technology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Felix Studt
- Institute of Catalysis Research and Technology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
- Institute for Chemical Technology and Polymer Chemistry, Karlsruhe Institute of Technology, Engesserstrasse 18, 76131 Karlsruhe, Germany
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9
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Chen K, Zornes A, Nguyen V, Wang B, Gan Z, Crossley SP, White JL. 17O Labeling Reveals Paired Active Sites in Zeolite Catalysts. J Am Chem Soc 2022; 144:16916-16929. [PMID: 36044727 DOI: 10.1021/jacs.2c05332] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Current needs for extending zeolite catalysts beyond traditional gas-phase hydrocarbon chemistry demand detailed characterization of active site structures, distributions, and hydrothermal impacts. A broad suite of homonuclear and heteronuclear NMR correlation experiments on dehydrated H-ZSM-5 catalysts with isotopically enriched 17O frameworks reveals that at least two types of paired active sites exist, the amount of which depends on the population of fully framework-coordinated tetrahedral Al (Al(IV)-1) and partially framework-coordinated tetrahedral Al (Al(IV)-2) sites, both of which can be denoted as (SiO)4-n-Al(OH)n. The relative amounts of Al(IV)-1 and Al(IV)-2 sites, and subsequent pairing, cannot be inferred from the catalyst Si/Al ratio, but depend on synthetic and postsynthetic modifications. Correlation experiments demonstrate that, on average, acidic hydroxyl groups from Al(IV)-1/Al(IV)-2 pairs are closer to one another than those from Al(IV)-1/Al(IV)-1 pairs, as supported by computational DFT calculations. Through-bond and through-space polarization transfer experiments exploiting 17O nuclei reveal a number of different acidic hydroxyl groups in varying Si/Al catalysts, the relative amounts of which change following postsynthetic modifications. Using room-temperature isotopic exchange methods, it was determined that 17O was homogeneously incorporated into the zeolite framework, while 17O → 27Al polarization transfer experiments demonstrated that 17O incorporation does not occur for extra-framework AlnOm species. Data from samples exposed to controlled hydrolysis indicates that nearest neighbor Al pairs in the framework are more susceptible to hydrolytic attack. The data reported here suggest that Al(IV)-1/Al(IV)-2 paired sites are synergistic sites leading to increased reactivity in both low- and high-temperature reactions. No evidence was found for paired framework/nonframework sites.
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Affiliation(s)
- Kuizhi Chen
- National High Magnetic Field Laboratory, Tallahassee, Florida 32310, United States
| | - Anya Zornes
- School of Chemical Engineering, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Vy Nguyen
- School of Chemical, Materials, and Biological Engineering, University of Oklahoma, Norman, Oklahoma 73019, United States
| | - Bin Wang
- School of Chemical, Materials, and Biological Engineering, University of Oklahoma, Norman, Oklahoma 73019, United States
| | - Zhehong Gan
- National High Magnetic Field Laboratory, Tallahassee, Florida 32310, United States
| | - Steven P Crossley
- School of Chemical, Materials, and Biological Engineering, University of Oklahoma, Norman, Oklahoma 73019, United States
| | - Jeffery L White
- School of Chemical Engineering, Oklahoma State University, Stillwater, Oklahoma 74078, United States
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10
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Gešvandtnerová M, Bučko T, Raybaud P, Chizallet C. Monomolecular mechanisms of isobutanol conversion to butenes catalyzed by acidic zeolites: alcohol isomerization as a key to the production of linear butenes. J Catal 2022. [DOI: 10.1016/j.jcat.2022.07.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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11
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Tang X, Chen W, Dong W, Liu Z, Yuan J, Xia H, Yi X, Zheng A. Framework aluminum distribution in ZSM-5 zeolite directed by organic structure-directing agents: a theoretical investigation. Catal Today 2022. [DOI: 10.1016/j.cattod.2022.06.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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12
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Marsden G, Kostetskyy P, Sekiya RS, Hoffman A, Lee S, Gounder R, Hibbitts D, Broadbelt LJ. Quantifying Effects of Active Site Proximity on Rates of Methanol Dehydration to Dimethyl Ether over Chabazite Zeolites through Microkinetic Modeling. ACS MATERIALS AU 2021; 2:163-175. [PMID: 36855771 PMCID: PMC9888634 DOI: 10.1021/acsmaterialsau.1c00057] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Control of the spatial proximity of Brønsted acid sites within the zeolite framework can result in materials with properties that are distinct from materials synthesized through conventional crystallization methods or available from commercial sources. Recent experimental evidence has shown that turnover rates of different acid-catalyzed reactions increase with the fraction of proximal sites in chabazite (CHA) zeolites. The catalytic conversion of oxygenates is an important research area, and the dehydration of methanol to dimethyl ether (DME) is a well-studied reaction as part of methanol-to-olefin chemistry catalyzed by solid acids. Published experimental data have shown that DME formation rates (per acid site) increase systematically with the fraction of proximal acid sites in the six-membered ring of CHA. Here, we probe the effect of acid site proximity in CHA on methanol dehydration rates using electronic structure calculations and microkinetic modeling to identify the primary causes of this chemistry and their relationship to the local structure of the catalyst at the nanoscale. We report a density functional theory-parametrized microkinetic model of methanol dehydration to DME, catalyzed by acidic CHA zeolite with direct comparison to experimental data. Effects of proximal acid sites on reaction rates were captured quantitatively for a range of operating conditions and catalyst compositions, with a focus on total paired acid site concentration and reactant clustering to form higher nuclearity complexes. Next-nearest neighbor paired acid sites were identified as promoting the formation of methanol trimer clusters rather than the inhibiting tetramer or pentamer clusters, resulting in large increases in the rate for DME production due to the lower energy barriers present in the concerted methanol trimer reaction pathway. The model framework developed in this study can be extended to other zeolite materials and reaction chemistries toward the goal of rational design and development of next-generation catalytic materials and chemical processes.
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Affiliation(s)
- Grant Marsden
- Department
of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United
States
| | - Pavlo Kostetskyy
- Department
of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United
States
| | - Ryoh-Suke Sekiya
- Department
of Chemical Engineering, University of Florida, 1030 Center, Drive
P.O. Box 116005, Gainesville, Florida 32611, United States
| | - Alexander Hoffman
- Department
of Chemical Engineering, University of Florida, 1030 Center, Drive
P.O. Box 116005, Gainesville, Florida 32611, United States
| | - Songhyun Lee
- Charles
D. Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, Indiana 47907, United States
| | - Rajamani Gounder
- Charles
D. Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, Indiana 47907, United States
| | - David Hibbitts
- Department
of Chemical Engineering, University of Florida, 1030 Center, Drive
P.O. Box 116005, Gainesville, Florida 32611, United States
| | - Linda J. Broadbelt
- Department
of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United
States,
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13
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Wang Z, Chu W, Zhao Z, Liu Z, Chen H, Xiao D, Gong K, Li F, Li X, Hou G. The Role of Organic and Inorganic Structure-Directing Agents in Selective Al Substitution of Zeolite. J Phys Chem Lett 2021; 12:9398-9406. [PMID: 34553943 DOI: 10.1021/acs.jpclett.1c01448] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Organic and inorganic structure-directing agents (SDAs) impact Al distributions in zeolite, but the insights into how SDAs manipulate Al distribution have not been elucidated yet. Herein, the roles of different SDAs such as cyclohexylamine (CHA), hexamethylenimine (HMI), and Na+ in selective Al substitution of MCM-49 zeolite are investigated comprehensively by multinuclear solid-state NMR. The results demonstrate that MCM-49 synthesized with HMI shows relatively more T6 and T7 Al, while more T2 Al is observed using CHA. The formation of T2 Al in both MCM-49(HMI) and MCM-49(CHA) is derived from Na+, while protonated HMIs show bias in incorporation of T6 and T7 Al. Most HMIs are occluded in protonated status, and about half of CHAs are occluded in nonprotonated status. The close spatial proximity between nonprotonated CHAs and Na+ synergistically promotes the formation of zeolite structure, leading to more Na+ ions occluded in the zeolite channel with preferential T2 Al substitution.
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Affiliation(s)
- Zhili Wang
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Weifeng Chu
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Zhenchao Zhao
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Zhengmao Liu
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hongyu Chen
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Dong Xiao
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Ke Gong
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fan Li
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiujie Li
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Guangjin Hou
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
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14
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Li C, Ferri P, Paris C, Moliner M, Boronat M, Corma A. Design and Synthesis of the Active Site Environment in Zeolite Catalysts for Selectively Manipulating Mechanistic Pathways. J Am Chem Soc 2021; 143:10718-10726. [PMID: 34240857 PMCID: PMC8529870 DOI: 10.1021/jacs.1c04818] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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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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Affiliation(s)
- Chengeng Li
- Instituto de Tecnología Química, Universitat Politècnica de València - Consejo Superior de Investigaciones Científicas, Avenida de los Naranjos s/n, 46022 Valencia, Spain
| | - Pau Ferri
- Instituto de Tecnología Química, Universitat Politècnica de València - Consejo Superior de Investigaciones Científicas, Avenida de los Naranjos s/n, 46022 Valencia, Spain
| | - Cecilia Paris
- Instituto de Tecnología Química, Universitat Politècnica de València - Consejo Superior de Investigaciones Científicas, Avenida de los Naranjos s/n, 46022 Valencia, Spain
| | - Manuel Moliner
- Instituto de Tecnología Química, Universitat Politècnica de València - Consejo Superior de Investigaciones Científicas, Avenida de los Naranjos s/n, 46022 Valencia, Spain
| | - Mercedes Boronat
- Instituto de Tecnología Química, Universitat Politècnica de València - Consejo Superior de Investigaciones Científicas, Avenida de los Naranjos s/n, 46022 Valencia, Spain
| | - Avelino Corma
- Instituto de Tecnología Química, Universitat Politècnica de València - Consejo Superior de Investigaciones Científicas, Avenida de los Naranjos s/n, 46022 Valencia, Spain
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15
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Developing quantitative synthesis-structure-function relations for framework aluminum arrangement effects in zeolite acid catalysis. J Catal 2021. [DOI: 10.1016/j.jcat.2021.04.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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16
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Kostetskyy P, Koninckx E, Broadbelt LJ. Probing Monomer and Dimer Adsorption Trends in the MFI Framework. J Phys Chem B 2021; 125:7199-7212. [PMID: 34165314 DOI: 10.1021/acs.jpcb.1c02929] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Porous aluminosilicates such as zeolites are ubiquitous catalysts for the production of high-value and industrially relevant commodity chemicals, including the conversion of hydrocarbons, amines, alcohols, and others. Bimolecular reactions are an important subclass of reactions that can occur on Brønsted acid sites of a zeolite catalyst. Kinetic modeling of these systems at the process scale requires the interaction energetics of reactants and the active sites to be described accurately. It is generally known that adsorption is a coverage-dependent phenomenon, with lower heats of adsorption observed for molecules at higher coverage. However, few studies have systematically investigated the coadsorption of molecules on a single active site, specifically focusing on the strength of interaction of the second adsorbate after the initial adsorption step. In this work, we quantify the unimolecular and bimolecular adsorption energies of varying adsorbates, including paraffins, olefins, alcohols, amines, and noncondensible gases in the acidic and siliceous ZSM-5 frameworks. As a special case, olefin adsorption was examined for physisorption and chemisorption regimes, characterized by π-complex, framework alkoxide and carbenium ion adsorption, respectively. The effects of functional groups and molecular size were quantified, and correlations that relate the adsorption of the second adsorbate identity to that of the first adsorbate are provided.
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Affiliation(s)
- Pavlo Kostetskyy
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Elsa Koninckx
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Linda J Broadbelt
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
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17
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Krishna SH, Jones CB, Gounder R. Dynamic Interconversion of Metal Active Site Ensembles in Zeolite Catalysis. Annu Rev Chem Biomol Eng 2021; 12:115-136. [PMID: 33826852 DOI: 10.1146/annurev-chembioeng-092120-010920] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Catalysis science is founded on understanding the structure, number, and reactivity of active sites. Kinetic models that consider active sites to be static and noninteracting entities are routinely successful in describing the behavior of heterogeneous catalysts. Yet, active site ensembles often restructure in response to their external environment and even during steady-state catalytic turnover, sometimes requiring non-mean-field kinetic treatments to describe distance-dependent interactions among sites. Such behavior is being recognized more frequently in modern catalysis research, with the advent of experimental methods to quantify turnover rates with increasing precision, an expanding arsenal of operando characterization tools, and computational descriptions of atomic structure and motion at chemical potentials and timescales increasingly relevant to reaction conditions. This review focuses on dynamic changes to metal active site ensembles on zeolite supports, which are silica-based crystalline materials substituted with Al that generate binding sites for isolated and low-nuclearity metal site ensembles. Metal sites can become solvated and mobilized during reaction, facilitating interactions among sites that change their nuclearity and function. Such intersite communication can be regulated by the zeolite support, resulting in non-single-site and potentially non-mean-field kinetic behavior arising from mechanisms of catalytic action that combine elements of those canonically associated with homogeneous and heterogeneous catalysis.We discuss recent literature examples that document dynamic active site behavior in metal-zeolites and outline methodologies to identify and interpret such behavior. We conclude with our outlook on future research directions to develop this evolving branch of catalysis science and harness it for practical applications.
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Affiliation(s)
- Siddarth H Krishna
- Charles D. Davidson School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, USA;
| | - Casey B Jones
- Charles D. Davidson School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, USA;
| | - Rajamani Gounder
- Charles D. Davidson School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, USA;
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18
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Kester PM, Crum JT, Li S, Schneider WF, Gounder R. Effects of Brønsted acid site proximity in chabazite zeolites on OH infrared spectra and protolytic propane cracking kinetics. J Catal 2021. [DOI: 10.1016/j.jcat.2020.12.038] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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19
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Bates JS, Gounder R. Kinetic effects of molecular clustering and solvation by extended networks in zeolite acid catalysis. Chem Sci 2021; 12:4699-4708. [PMID: 34168752 PMCID: PMC8179612 DOI: 10.1039/d1sc00151e] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 02/17/2021] [Indexed: 01/06/2023] Open
Abstract
Reactions catalyzed within porous inorganic and organic materials and at electrochemical interfaces commonly occur at high coverage and in condensed media, causing turnover rates to depend strongly on interfacial structure and composition, collectively referred to as "solvent effects". Transition state theory treatments define how solvation phenomena enter kinetic rate expressions, and identify two distinct types of solvent effects that originate from molecular clustering and from the solvation of such clusters by extended solvent networks. We review examples from the recent literature that investigate reactions within microporous zeolite catalysts to illustrate these concepts, and provide a critical appraisal of open questions in the field where future research can aid in developing new chemistry and catalyst design principles.
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Affiliation(s)
- Jason S Bates
- Charles D. Davidson School of Chemical Engineering, Purdue University 480 Stadium Mall Drive West Lafayette IN 47907 USA
| | - Rajamani Gounder
- Charles D. Davidson School of Chemical Engineering, Purdue University 480 Stadium Mall Drive West Lafayette IN 47907 USA
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20
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Harris JW, Bates JS, Bukowski BC, Greeley J, Gounder R. Opportunities in Catalysis over Metal-Zeotypes Enabled by Descriptions of Active Centers Beyond Their Binding Site. ACS Catal 2020. [DOI: 10.1021/acscatal.0c02102] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- James W. Harris
- Department of Chemical and Biological Engineering, The University of Alabama, Box 870203, Tuscaloosa, Alabama 35487, United States
| | - Jason S. Bates
- Charles D. Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, Indiana 47907, United States
| | - Brandon C. Bukowski
- Charles D. Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, Indiana 47907, United States
| | - Jeffrey Greeley
- Charles D. Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, Indiana 47907, United States
| | - Rajamani Gounder
- Charles D. Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, Indiana 47907, United States
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