Synthesis of Lignin-Derived Bisphenols Catalyzed by Lignosulfonic Acid in Water for Polycarbonate Synthesis

Lignosulfonic acid, a byproduct of the paper industry, was demonstrated to be an efficient and green catalyst in water for the stoichiometric condensation of creosol with formaldehyde to synthesize lignin-derived renewable bisphenols. The distribution and structures of the products were confirmed by 1 H NMR, 13 C NMR, and FTIR spectroscopy and X-ray analysis; furthermore, a possible reaction mechanism was proposed. A polycarbonate was prepared from the bisphenol product and characterized as a model application, and thermogravimetric analysis (TGA) showed that decomposition occurred in a single stage with the maximum rate of degradation at approximately 420 °C. Differential scanning calorimetry (DSC) analysis showed that the glass transition temperature and melting peak of the polycarbonate were approximately 122 and 314 °C, respectively. The environmentally friendly characteristics of this study are featured by the integrated utilization of a biorenewable feedstock, a green biomacromolecule catalyst, and a green solvent for the preparation of valuable biochemicals and materials. Graphical Phenomenal phenols: Lignosulfonic acid, a byproduct of the paper industry, is demonstrated to be an efficient, green, and reusable catalyst in water for the stoichiometric condensation of creosol with formaldehyde to synthesize lignin-derived renewable bisphenols. A polycarbonate is prepared and characterized as a model application of the as-prepared bisphenol.