The ability of solvents to dissolve or swell a variety of
isolated lignins increases as the hydrogen-bonding
capacities of the solvents increase and as their Hildeb-
rand solubility parameters approach a value of around
eleven. Lower molecular weight lignin fractions are
soluble in organic solvents with weak or moderate
hydrogen-bonding capacity with a wider range of Hil-
debrand solubility parameters than are the higher
molecular weight fractions [17]. Further studies by
Schuerch [17] also discovered that the solubility of lig-
nin is better in the mixture than in either solvent alone.
In this study, 5.0 g of the ash-AQ lignin was used as the
starting material for the solvent fractionation, which
was carried out in three separate extraction steps