Abstract: An inverse gas chromatographic (IGC) method has been used to measure the solubility parameters (δ2) of organosolv lignin at the absolute temperatures from 333.15 K to 373.15 K. The test probe solvents were n-octane (n-C8), n-decane (n-C10), n-dodecane (n-C12), and n-tetradecane (n-C14). The specific retention volumes of the solvents (V0g), the molar enthalpy of sorption (ΔHs1), the partial molar enthalpy of mixing at infinite dilution (ΔH∞1), the molar enthalpy of vaporization (ΔHv), the activity coefficients at infinite dilution (Ω∞1), and Flory-Huggins inter action parameters (χ∞12) between organosolv lignin and probe solvents were obtained. The results showed that the above four probes are poor solvents for organosolv lignin; at the same temperature, the χ∞12 reduced with the increase of the carbon number of probe solvents. The average solubility parameter of organosolv lignin was determined as 19.03 (J\5cm-3)1/2.

Key words: organosolv lignin, solubility parameter, inverse gas chromatography (IGC)