A series of renewable triphenylmethane-type polyphenols (TPs) were synthesized from lignin-derived guaiacols (methylguaiacol and propylguaiacol) and aldehydes (4-hydroxybenzaldehyde, vanillin, and syringaldehyde). By converting guaiacols to catechols through ortho-demethylation, the newly formed phenolic para site remarkably improved the reactivity as reflected by conversion of TPs. Optimized reagent molar ratios were aldehyde/catechol (1:4) and aldehyde/H2SO4 (1:3). A typical TP (VAN-M-CAT) was converted to glycidyl ether (GE-VAN-M-CAT) to examine its feasibility as precursor to epoxy thermosets. The resulting network exhibited excellent glassy modulus (12.3 GPa), glass transition temperature (167 ○C), and thermal stability, which were attributed to the rigid triphenylmethane framework, high functionality (n = 5), and high cross-link density. Lignin derived phenol (2-methoxy-4-propylphenol) was used to synthesize a biomass based ligand (DHEL). This ligand's effectiveness in metal deposit removal from exhumed plastic drinking water pipe was examined. The total metal deposited on 3 cm pipe segments was first characterized and heterogeneous metal loading (μg/dm2) along consecutive pipe segments was found. Fe was the most abundant metal species detected, followed by Mn, Ca, Zn, Mg, Cu, Pb and Al. Results showed DHEL effectively removed metal deposits from exhumed plastic pipe surfaces. More than 95% of total metal loadings were removed when DHEL dosage was ≥ 5 mM. Both first order and second order kinetic models were used to fit the experimental data. DHEL showed higher favorability for Cu and Zn rather than Fe, Mn, and Pb. DHEL-metal removal mechanisms were proposed as: 1) ligand-promoted minerals dissolution, and 2) ligand-metal complex formation.

Renewable polymers and ligands derived from lignin

255th National Meeting (2018)

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