Presentation description

Biomass materials present an abundantly available and environmentally sustainable alternative to petroleum in the production of chemicals and energy. In plastics production, the furanic compound 2,5-Furandicarboxylic acid (FDCA) is a precursor to a sustainable biobased alternative for petroleum derived polyethylene terephthalate (PET). The oxidation of biomass-derived 2,5-bis(hydroxymethyl)furan (BHMF) to FDCA is herein studied in order to examine the effectiveness of various 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) catalysts in the conversion of BHMF to FDCA. Cyclic voltammetry was used to quantitatively investigate catalysis in a TEMPO solution upon sequential addition of BHMF substrate. Subsequent voltammetric analysis of the electrochemical reversibility of each TEMPO catalyst allowed for prediction of each catalyst's effectiveness in the oxidation of BHMF to FDCA. Catalysts Acetamido-TEMPO (ACT), Methoxy-TEMPO (MT), and TEMPO demonstrated voltammetric reversibility and thus were hypothesized to exhibit effective conversion in the electrosynthesis of FDCA. Conversely, Amino-TEMPO (AT) and Oxo-TEMPO (OT) demonstrated voltammetrically irreversible catalytic behavior upon substrate addition and were therefore predicted to achieve only intermediate oxidation. Bulk electrolysis experiments of each TEMPO catalyst at constant oxidative overpotential were conducted to reinforce the catalytic predictions made from the cyclic voltammetry studies. Product analysis via ultra high performance liquid chromatography/mass spectrometry (UHPLC/MS) confirmed that voltammetrically reversible catalysts ACT, MT, and TEMPO facilitated near-complete conversion of BHMF to FDCA, while voltammetrically irreversible AT and OT facilitated production of only intermediate oxidative products. Ultimately, the fundamental examination of these TEMPO catalysts' effectiveness in the conversion of BHMF to FDCA opens opportunities to improve the efficiency of electrosynthesis of biomass-derived furanic compounds.