• Login
    View Item 
    •   Home
    • UA Faculty Research
    • UA Faculty Publications
    • View Item
    •   Home
    • UA Faculty Research
    • UA Faculty Publications
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

    All of UA Campus RepositoryCommunitiesTitleAuthorsIssue DateSubmit DateSubjectsPublisherJournalThis CollectionTitleAuthorsIssue DateSubmit DateSubjectsPublisherJournal

    My Account

    LoginRegister

    About

    AboutUA Faculty PublicationsUA DissertationsUA Master's ThesesUA Honors ThesesUA PressUA YearbooksUA CatalogsUA Libraries

    Statistics

    Most Popular ItemsStatistics by CountryMost Popular Authors

    Understanding hydroxide reactions with guanidinium-based anion exchange polymers under conditions relevant to bipolar membrane electrodialysis

    • CSV
    • RefMan
    • EndNote
    • BibTex
    • RefWorks
    Thumbnail
    Name:
    Guanidinium-Final-line.pdf
    Embargo:
    2021-03-18
    Size:
    363.7Kb
    Format:
    PDF
    Description:
    Final Accepted Manuscript
    Download
    Author
    Farrell, James
    Martínez, Rodrigo J.
    Affiliation
    Univ Arizona, Dept Chem & Environm Engn
    Issue Date
    2019-05-01
    
    Metadata
    Show full item record
    Publisher
    ELSEVIER SCIENCE BV
    Citation
    Farrell, J., & Martínez, R. J. (2019). Understanding Hydroxide Reactions with Guanidinium-based Anion Exchange Polymers Under Conditions Relevant to Bipolar Membrane Electrodialysis. Computational and Theoretical Chemistry.
    Journal
    COMPUTATIONAL AND THEORETICAL CHEMISTRY
    Rights
    © 2019 Elsevier B.V. All rights reserved.
    Collection Information
    This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.
    Abstract
    Anion exchange polymers are susceptible to loss of cationic functionality as a result of nucleophilic attack by hydroxide ions. This research investigated the stability of two guanidinium-based cations as anion exchange functional groups under conditions relevant to bipolar membrane electrodialysis. Density functional theory simulations were performed to investigate reaction energies and activation barriers for reactions of hydroxide ions with pentamethylguanidinium (PMG) and hexamethylguanidinium (HMG) cations bound to a diaryl ketone polymer backbone. The effect of physically adsorbed chloride and hydroxide ions, and chemically adsorbed hydroxide ions, on reaction energetics were determined. Fukui functions for nucleophilic attack were used to identify locations most likely to undergo reactions with hydroxide ions. For the PMG species, the most likely bond cleavage reactions were highly exergonic, Delta G(rxn)(0) with AGE values as large as - 46 kcal/mol and activation barriers less than 10 kcal/mol. Chemisorption of hydroxide ions on both PMG and HMG cations was energetically favorable, with activation barriers of 5.3 and 2.7 kcal/mol, and resulted in loss of cationic functionality. Anion adsorption changed the reactivity of both PMG and HMG structures towards nucleophilic attack. For nucleophilic attack at the phenyl carbon atom, adsorption of OH- on the guanidinium carbon atom made PMG less reactive, while adsorption of Cl- made HMG less reactive. Bond cleavage and loss of cationic functionality was a two or three step process involving addition of OH- to the phenyl or guanidinium carbon atoms, followed by bond stretching or deprotonation of the added hydroxide species. For PMG species, deprotonation of the hydroxide resulted in bond cleavage or produced metastable species that decomposed with activation barriers less than 2 kcal/mol. HMG species were more stable with respect to this degradation mechanism, having activation barriers for bond cleavage ranging from 17 to 29 kcal/mol.
    Note
    24 month embargo; available online 18 March 2019.
    ISSN
    2210271X
    DOI
    10.1016/j.comptc.2019.03.020
    Version
    Final accepted manuscript
    Sponsors
    National Science Foundation Chemical, Bioengineering, Environmental and Transport Systems (CBET) Division [1604857]; Consejo Nacional de Ciencia y Tecnologia (CONACYT), Mexico [409178]
    Additional Links
    https://linkinghub.elsevier.com/retrieve/pii/S2210271X19300829
    ae974a485f413a2113503eed53cd6c53
    10.1016/j.comptc.2019.03.020
    Scopus Count
    Collections
    UA Faculty Publications

    entitlement

     
    The University of Arizona Libraries | 1510 E. University Blvd. | Tucson, AZ 85721-0055
    Tel 520-621-6442 | repository@u.library.arizona.edu
    DSpace software copyright © 2002-2017  DuraSpace
    Quick Guide | Contact Us | Send Feedback
    Open Repository is a service operated by 
    Atmire NV
     

    Export search results

    The export option will allow you to export the current search results of the entered query to a file. Different formats are available for download. To export the items, click on the button corresponding with the preferred download format.

    By default, clicking on the export buttons will result in a download of the allowed maximum amount of items.

    To select a subset of the search results, click "Selective Export" button and make a selection of the items you want to export. The amount of items that can be exported at once is similarly restricted as the full export.

    After making a selection, click one of the export format buttons. The amount of items that will be exported is indicated in the bubble next to export format.