Optimization and Potentials of Kraft Lignin Hydrolysates Obtained by Subcritical Water at Moderate Temperatures

Kraft lignin was treated with subcritical water at moderate temperatures (120–220 °C) in different gas atmospheres, the goal of optimizing its depolymerization under mild conditions. Lignin observed and compared using homogeneous heterogeneous catalysts both nitrogen carbon dioxide atmospheres. The most important treatment parameters for maximum highest yields phenolic other aromatic monomers were optimized. influence process temperature, pressure, time atmospheres defined optimized liberation into aqueous phase. total phenols aromatics atmosphere 150 °C, whereas required higher (200 a comparable efficiency. effects phenol addition as capping agent Phenol caused remarkable increase content phase; however, it did not significantly affect contents aromatics. antioxidant properties hydrolysates obtained compared, correlated contents, discussed, showing promising potential