title: Ionic Liquid Character of Zinc Chloride Hydrates Define Solvent Characteristics that Afford the Solubility of Cellulose.
abstract: The recently described ionic liquid structure of the three equivalent hydrate of zinc chloride (ZnCl2·R H2O, R = 3, existing as [Zn(OH2)6][ZnCl4]) explains the solubility of cellulose in this medium. Only hydrate compositions in the narrow range of 3 - x < R < 3 + x with x ≈ 1 dissolve cellulose. Once dissolved, the cellulose remains in solution up to the R = 9 hydrate. Neutron diffraction and differential pair distribution function analysis of cellulose and model compound solutions (1 wt % cellulose in the R = 3 hydrate and 1 wt % ethanol in the R = 3 hydrate and the ZnCl2·3 ethanol liquid) coupled with detailed solubility measurements suggest that cellulose solubility occurs via coordination of the primary OH to the hydrated zinc cation with ring hydroxyls forming part of a second coordination shell around the cation of the ionic liquid.
authors.affiliation: Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States.|Department of Forest Biomaterials, North Carolina State University , Raleigh, North Carolina 27695-8001, United States.
authors.forename: Sanghamitra
authors.initials: S
authors.lastname: Sen
authors.affiliation: Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States.
authors.forename: Bradley P
authors.initials: BP
authors.lastname: Losey
authors.affiliation: Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States.
authors.forename: Elijah E
authors.initials: EE
authors.lastname: Gordon
authors.affiliation: Department of Forest Biomaterials, North Carolina State University , Raleigh, North Carolina 27695-8001, United States.
authors.forename: Dimitris S
authors.initials: DS
authors.lastname: Argyropoulos
authors.affiliation: Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States.
authors.forename: James D
authors.initials: JD
authors.lastname: Martin
mesh_terms: D002482:Cellulose / Q000737:chemistry*; D002712:Chlorides / Q000737:chemistry*; D052578:Ionic Liquids / Q000737:chemistry*; D008968:Molecular Conformation; D012995:Solubility; D012997:Solvents / Q000737:chemistry*; D014867:Water / Q000737:chemistry; D017967:Zinc Compounds / Q000737:chemistry*
chemical_list: D002712:Chlorides; D052578:Ionic Liquids; D012997:Solvents; D017967:Zinc Compounds; D014867:Water; C016837:zinc chloride; D002482:Cellulose