Understanding sulfonated kraft lignin re-polymerization by ultrafast reactions in supercritical water

Re-polymerization reactions are a commonly reported issue on the way to higher recovery of monomers from lignin. The reactivity obtained lignin depolymerization and their contribution re-polymerization in supercritical water (SCW) was investigated. Sulfonated Kraft (SKL) used along with four monomers: vanillin, vanillic acid, vanillyl alcohol acetovanillone. Indulin also employed as reference understand SKL SCW. formation diarylmethane structures detected HSQC spectra solid residue after SCW process. Lignin released fragments free phenolic β-O-4 structures, well monomeric product involved o-o´ o-p´ structures. Chemical structure its polymeric process remarkably similar, shown by HSQC, indicating that occur through cross-linking polymerization, mainly fractions low molecular weight products. • Study role model compounds Reactivity without sulfonated kraft followed presence cause an increased yield heavier assigned Reaction mechanism for diarylmethanes is proposed