Demethylation and tannin-like properties of guaiacyl/syringyl-type and syringyl-type dehydrogenation polymers using iodocyclohexane

Abstract The demethylation of guaiacyl/syringyl (G/S)-type (G/S = 1/1) and syringyl (S)-type dehydrogenation polymers (DHPs) using iodocyclohexane (ICH) under reflux in DMF was performed to afford demethylated G/S- S-DHPs moderate yields. Along with significant structural changes, such as side-chain cleavage recondensation, observed heteronuclear single quantum coherence (HSQC) NMR spectra, the phenolic-OH content DHPs increased, expected. tannin-like properties, 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging ability, iron(III) binding bovine serum albumin (BSA) adsorption increased increasing reaction time. In particular, BSA ability significantly enhanced by S-DHPs, better than that G-DHP reported previously. These results indicate hardwood lignin containing both G S units is more suitable softwood only for functionalization through into a polymer, which has applications natural oxidant, metal adsorbent, protein adsorbent.