title: Solubility of Organosolv Lignin in γ-Valerolactone/Water Binary Mixtures.
abstract: The solubility of lignin in a mixture of γ-valerolactone (GVL) and water at different weight ratios was measured using the Hildebrand solubility parameters. Based on the molecular structure of lignin, its solubility parameter (δ-value) was calculated as 25.5 MPa1/2. The δ-value for aqueous GVL solvent increased from 23.1 MPa1/2for pure GVL to 45.6 MPa1/2for pure water. Therefore, the lignin solubility was predicted to increase with increasing GVL concentration in the aqueous mixture up to approximately 92-96 wt % of GVL. A ternary diagram describing the phase behavior of water-GVL-lignin mixtures at room temperature was constructed based on the experimental results. The three-component system exhibited a complex behavior with a liquid-liquid and solid-liquid-liquid phase split. The efficiency of the selected fractionation trials in a previous work was validated using the ternary solubility diagram. A promising recovery pathway and lignin isolation method were deduced from the results of this work.
authors.affiliation: Department of Forest Products Technology, Aalto University, Vuorimiehentie 1, 02150, Espoo, Finland.
authors.forename: Huy Quang
authors.identifier: http://orcid.org/0000-0001-6290-3131
authors.initials: HQ
authors.lastname: Lê
authors.affiliation: Department of Biotechnology and Chemical Technology, Aalto University, Kemistintie 1, 02150, Espoo, Finland.
authors.forename: Anna
authors.initials: A
authors.lastname: Zaitseva
authors.affiliation: Department of Biotechnology and Chemical Technology, Aalto University, Kemistintie 1, 02150, Espoo, Finland.
authors.forename: Juha-Pekka
authors.identifier: http://orcid.org/0000-0002-0857-6608
authors.initials: JP
authors.lastname: Pokki
authors.affiliation: Department of Forest Products Technology, Aalto University, Vuorimiehentie 1, 02150, Espoo, Finland.
authors.forename: Marina
authors.initials: M
authors.lastname: Ståhl
authors.affiliation: Department of Biotechnology and Chemical Technology, Aalto University, Kemistintie 1, 02150, Espoo, Finland.
authors.forename: Ville
authors.identifier: http://orcid.org/0000-0001-9773-0998
authors.initials: V
authors.lastname: Alopaeus
authors.affiliation: Department of Forest Products Technology, Aalto University, Vuorimiehentie 1, 02150, Espoo, Finland. herbert.sixta@aalto.fi.
authors.forename: Herbert
authors.initials: H
authors.lastname: Sixta
mesh_terms: D005591:Chemical Fractionation; D007783:Lactones / Q000737:chemistry*; D008031:Lignin / Q000737:chemistry*; D012995:Solubility; D014867:Water / Q000737:chemistry
chemical_list: D007783:Lactones; D014867:Water; D008031:Lignin; C037556:gamma-valerolactone
keywords: Hildebrand parameters; organosolv lignin; solubility; γ-valerolactone