title: Use of polyoxometalate catalysts in ionic liquids to enhance the dissolution and delignification of woody biomass.
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 ([C(2) mim]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.
authors.affiliation: Center for Green Manufacturing, Department of Chemistry, The University of Alabama, Tuscaloosa, USA.
authors.forename: Ning
authors.initials: N
authors.lastname: Sun
authors.forename: Xinyu
authors.initials: X
authors.lastname: Jiang
authors.forename: Mirela L
authors.initials: ML
authors.lastname: Maxim
authors.forename: Andreas
authors.initials: A
authors.lastname: Metlen
authors.forename: Robin D
authors.initials: RD
authors.lastname: Rogers
mesh_terms: D018533:Biomass; D002384:Catalysis; D006863:Hydrogen-Ion Concentration; D007093:Imidazoles / Q000737:chemistry; D052578:Ionic Liquids / Q000737:chemistry*; D008031:Lignin / Q000737:chemistry* / Q000302:isolation & purification*; D013997:Time Factors; D017973:Tungsten Compounds / Q000737:chemistry*; D014934:Wood / Q000737:chemistry*; D000099294:Polyoxometalates
chemical_list: D007093:Imidazoles; D052578:Ionic Liquids; D008031:Lignin; D017973:Tungsten Compounds; C102296:polyoxometalate I; D000099294:Polyoxometalates; C518739:1-ethyl-3-methylimidazolium