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Use of Polyoxometalate Catalysts in Ionic Liquids to Enhance the Dissolution and Delignification of Woody Biomass

Authors

  • Ning Sun,

    1. Center for Green Manufacturing and Department of Chemistry, The University of Alabama, Tuscaloosa AL (USA), Fax: (+1) 205-348-0823
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  • Dr. Xinyu Jiang,

    1. Center for Green Manufacturing and Department of Chemistry, The University of Alabama, Tuscaloosa AL (USA), Fax: (+1) 205-348-0823
    2. Current address: School of Chemistry and Chemical Engineering, Central South University, Changsha (People's Republic of China)
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  • Mirela L. Maxim,

    1. Center for Green Manufacturing and Department of Chemistry, The University of Alabama, Tuscaloosa AL (USA), Fax: (+1) 205-348-0823
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  • Dr. Andreas Metlen,

    1. QUILL and School of Chemistry and Chemical Engineering, The Queen's University of Belfast, Belfast, BT9 5AG, Northern Ireland (UK)
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  • Prof. Robin D. Rogers

    Corresponding author
    1. Center for Green Manufacturing and Department of Chemistry, The University of Alabama, Tuscaloosa AL (USA), Fax: (+1) 205-348-0823
    2. QUILL and School of Chemistry and Chemical Engineering, The Queen's University of Belfast, Belfast, BT9 5AG, Northern Ireland (UK)
    • Center for Green Manufacturing and Department of Chemistry, The University of Alabama, Tuscaloosa AL (USA), Fax: (+1) 205-348-0823
    Search for more papers by this author

Abstract

A well-known polyoxometalate, [PV2Mo10O40]5−, in both acidic (acidic POM, H5[PV2Mo10O40]) and ionic liquid-compatible form ([C2mim]POM, [1-ethyl-3-methylimidazolium]4H[PV2Mo10O40]), has been studied as a catalyst for the dissolution and delignification of wood in the ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate ([C2mim]OAc). Differences were observed with variables such as the form of POM, POM loading, and reaction conditions. Generally, the addition of POM leads to a faster dissolution, a lower lignin content in the recovered cellulose-rich materials (isolated pulp), and a lower isolated yield of lignin due to its oxidation. Acidic POM decreases the lignin content of the pulp without compromising the yield of the pulp. [C2mim]POM in the IL facilitates greater delignification (lower lignin content in pulp) than the IL with acidic POM; however, the overall pulp yield is also lower indicating some degradation of the carbohydrates. The POM can be recovered with [C2mim]OAc after evaporation of the reconstitution solvent (e.g., acetone/water) and can be reused, albeit with some loss of POM and loss of POM activity under the current conditions.

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