Selective conversion of hardwood lignin into syringyl methyl benzofuran using p -cresol

Hardwood lignin in eucalyptus was first converted to hardwood lignocresol through a phase separation process utilizing wood meal, sulfuric acid, and p -cresol at ambient temperature. A syringyl methyl benzofuran, S2 was selectively obtained via a syringyl-type phenolic dimer with a coumaran ring, S1 by NaOH treatments of hardwood lignocresol at 170 °C. Our process controls the reactivity of C α linkages, C β -aryl-ethers, and C γ -OH in sequence, successfully resulting in a high yield of specific aromatic chemicals from hardwood lignin based on the successiveness of C β -aryl-ethers between syringyl units.