MODIFICATION OF HIGH-YIELD PULPS WITH POLYETHYLENE GLYCOLS .1. MODEL-COMPOUND AND ISOLATED LIGNIN STUDIES

Phenolic hydroxyl groups in three lignin model compounds, guaiacol, acetoguaiacone, and dehydrodiisoeugenol, and in organosolv lignin were blocked by etherification with polyethylene glycol (PEG). Polyethylene glycol modification, even at a low degree of substitution, greatly enhanced the hydrophilicity of the substrate, producing water-soluble substances. When etherified by reaction with PEG-mesylate, the lignin dimer model compound, dehydrodiisoeugenol, was stabilized considerably against light-induced yellowing.