ACS Publications. Most Trusted. Most Cited. Most Read
My Activity

Figure 1Loading Img

Carbocation Stability in H-ZSM5 at High Temperature

View Author Information
National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
Material Science Division, Argonne National Laboratory, 9700 South Cass Avenue B109, Lemont, Illinois 60439, United States
*E-mail [email protected] (G.T.B.).
Cite this: J. Phys. Chem. A 2015, 119, 46, 11397–11405
Publication Date (Web):October 26, 2015
Copyright © 2015 American Chemical Society

    Article Views





    Read OnlinePDF (4 MB)
    Supporting Info (1)»


    Abstract Image

    Zeolites are common catalysts for multiple industrial applications, including alcohol dehydration to produce olefins, and given their commercial importance, reaction mechanisms in zeolites have long been proposed and studied. Some proposed reaction mechanisms for alcohol dehydration exhibit noncyclic carbocation intermediates or transition states that resemble carbocations, and several previous studies suggest that the tert-butyl cation is the only noncyclic cation more stable than the corresponding chemisorbed species with the hydrocarbon bound to the framework oxygen (i.e., an alkoxide). To determine if carbocations can exist at high temperatures in zeolites, where these catalysts are finding new applications for biomass vapor-phase upgrading (∼500 °C), the stability of carbocations and the corresponding alkoxides were calculated with two ONIOM embedding methods (M06-2X/6-311G(d,p):M06-2X/3-21G) and (PBE-D3/6-311G(d,p):PBE-D3/3-21G) and plane-wave density functional theory (DFT) using the PBE functional corrected with entropic and Tkatchenko–Scheffler van der Waals corrections. The embedding methods tested are unreliable at finding minima for primary carbocations, and only secondary or higher carbocations can be described with embedding methods consistent with the periodic DFT results. The relative energy between the carbocations and alkoxides differs significantly between the embedding and the periodic DFT methods. The difference is between ∼0.23 and 14.30 kcal/mol depending on the molecule, the model, and the functional chosen for the embedding method. At high temperatures, the pw-DFT calculations predict that the allyl, isopropyl, and sec-butyl cations exhibit negligible populations while acetyl and tert-butyl cations exhibit significant populations (>10%). Moreover, the periodic DFT results indicate that mechanisms including secondary and tertiary carbocations intermediates or carbocations stabilized by adjacent oxygen or double bonds are possible at high temperatures relevant to some industrial uses of zeolite catalysts, although as the minority species in most cases.

    Supporting Information

    Jump To

    The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.jpca.5b07025.

    • Figures of the ONIOM models used in this study, the effect of water in the zeolite cavity and van der Waals forces on the carbocation stability, and geometry files for the ONIOM and PBC inputs (PDF)

    Terms & Conditions

    Most electronic Supporting Information files are available without a subscription to ACS Web Editions. Such files may be downloaded by article for research use (if there is a public use license linked to the relevant article, that license may permit other uses). Permission may be obtained from ACS for other uses through requests via the RightsLink permission system:

    Cited By

    This article is cited by 14 publications.

    1. Céline Chizallet, Christophe Bouchy, Kim Larmier, Gerhard Pirngruber. Molecular Views on Mechanisms of Brønsted Acid-Catalyzed Reactions in Zeolites. Chemical Reviews 2023, 123 (9) , 6107-6196.
    2. Brandon C. Knott, Claire T. Nimlos, David J. Robichaud, Mark R. Nimlos, Seonah Kim, and Rajamani Gounder . Consideration of the Aluminum Distribution in Zeolites in Theoretical and Experimental Catalysis Research. ACS Catalysis 2018, 8 (2) , 770-784.
    3. Pieter Cnudde, Michel Waroquier, Veronique Van Speybroeck. Universal descriptors for zeolite topology and acidity to predict the stability of butene cracking intermediates. Catalysis Science & Technology 2023, 13 (16) , 4857-4872.
    4. Yeonjoon Kim, Mohammed A. Jabed, David M. Price, Dmitri Kilin, Seonah Kim. Toward rational design of supported vanadia catalysts of lignin conversion to phenol. Chemical Engineering Journal 2022, 446 , 136965.
    5. Hong Ma, Jian Liao, Zhihong Wei, Xinxin Tian, Junfen Li, Yan-Yan Chen, Sen Wang, Hao Wang, Mei Dong, Zhangfeng Qin, Jianguo Wang, Weibin Fan. Trimethyloxonium ion – a zeolite confined mobile and efficient methyl carrier at low temperatures: a DFT study coupled with microkinetic analysis. Catalysis Science & Technology 2022, 12 (10) , 3328-3342.
    6. Elena Pérez-Guevara, Jose M. G. Molinillo, María José Franco, Enrique J. Martínez de la Ossa, Juana Frontela, Jesús Lázaro. Study by NMR of Liquid-Phase Alkylation of Toluene with Hex-1-ene: Effect of Catalyst on Selectivity. Petroleum Chemistry 2020, 60 (7) , 810-817.
    7. Lienda Handojo, Megawati Zunita, Antonius Indarto. Molecular Study of Phenyl Formation on ZSM-5: Comparison between Surface and Gas Phase Reactions. Polycyclic Aromatic Compounds 2020, 40 (2) , 372-381.
    8. Jianwen Liu, Yaru Yin, Xian-Zhu Fu, Jing-Li Luo. Stability of C3-C6 carbonium ions inside zeolites: A first principles study. Applied Surface Science 2020, 503 , 144148.
    9. Larissa Y. Kunz, Lintao Bu, Brandon C. Knott, Cong Liu, Mark R. Nimlos, Rajeev S. Assary, Larry A. Curtiss, David J. Robichaud, Seonah Kim. Theoretical Determination of Size Effects in Zeolite-Catalyzed Alcohol Dehydration. Catalysts 2019, 9 (9) , 700.
    10. D. A. Klumpp. Carbocations. 2019, 335-363.
    11. Philipp N. Plessow, Felix Studt. Olefin methylation and cracking reactions in H-SSZ-13 investigated with ab initio and DFT calculations. Catalysis Science & Technology 2018, 8 (17) , 4420-4429.
    12. Peter N. Ciesielski, M. Brennan Pecha, Vivek S. Bharadwaj, Calvin Mukarakate, G. Jeremy Leong, Branden Kappes, Michael F. Crowley, Seonah Kim, Thomas D. Foust, Mark R. Nimlos. Advancing catalytic fast pyrolysis through integrated multiscale modeling and experimentation: Challenges, progress, and perspectives. WIREs Energy and Environment 2018, 7 (4)
    13. P. Cnudde, K. De Wispelaere, J. Van der Mynsbrugge, M. Waroquier, V. Van Speybroeck. Effect of temperature and branching on the nature and stability of alkene cracking intermediates in H-ZSM-5. Journal of Catalysis 2017, 345 , 53-69.
    14. L. Y. Jia, M. Raad, S. Hamieh, J. Toufaily, T. Hamieh, M. M. Bettahar, G. Mauviel, M. Tarrighi, L. Pinard, A. Dufour. Catalytic fast pyrolysis of biomass: superior selectivity of hierarchical zeolites to aromatics. Green Chemistry 2017, 19 (22) , 5442-5459.

    Pair your accounts.

    Export articles to Mendeley

    Get article recommendations from ACS based on references in your Mendeley library.

    Pair your accounts.

    Export articles to Mendeley

    Get article recommendations from ACS based on references in your Mendeley library.

    You’ve supercharged your research process with ACS and Mendeley!

    STEP 1:
    Click to create an ACS ID

    Please note: If you switch to a different device, you may be asked to login again with only your ACS ID.

    Please note: If you switch to a different device, you may be asked to login again with only your ACS ID.

    Please note: If you switch to a different device, you may be asked to login again with only your ACS ID.

    Your Mendeley pairing has expired. Please reconnect