2 5 furan dicarboxylic acid

Chloroauric acid (Strem
Chemicals, 99.8%); palladium chloride (Sigma-Aldrich, >99.9%);
poly(vinyl
alcohol) (Sigma-Aldrich, M_w 9000–10,000,
80% hydrolyzed); sodium borohydride (Sigma-Aldrich, 99.99%); 5-hydroxymethyl-2-furancarboxylic
acid (Carbosynth, >97.0%); distilled water millipore (18.2 MΩ·cm
at 25 °C); 5-hydroxymethylfurfural (Sigma-Aldrich, >99.0%);
5-formyl-2-furancarboxylic
acid (Fluorochem); 2,5-furandicarboxylic acid (Sigma-Aldrich, 97%);
molecular O₂ (BOC, >99.95%); Nafion (Sigma-Aldrich,
5 wt
% in lower aliphatic alcohols and water, contains 15–20% water);
sodium hydrogen carbonate (Fisher Scientific, >99.5%); sodium hydroxide
(Fisher Scientific); Carbon Vulcan XC-72R (Cabot Corporation); ABTS
(2,2′-azinobis [3-ethylbenzothiazoline-6-sulfonic acid]-diammonium
salt) (Sigma-Aldrich, ≥98%); horseradish peroxidase (Sigma-Aldrich,
141.9 U/mg solid); hydrogen peroxide (Fisher Scientific, 30 wt %).

A series of high-molecular-weight poly(alkylene furanoate) and poly(alkylene terephthalate) samples were synthesized by applying melt polycondensation as described in our previous studies [23 (link),24 (link)].
Dimethyl terephthalate (DMT) was obtained from Du Pont De Nemours Co (Hamm, Germany) and 2,5-furan dicarboxylic acid (purum 97%) was purchased from Sigma-Aldrich Chemical Co (Chemie GmbH, Hamburg, Germany). Tetrabutyl titanate (TBT) catalyst of analytical grade; 1,2-ethanediol, 1,3-propanediol, both of analytical grade; and 1,4-cyclohexanedimethanol (CHDM, 70/30 trans/cis, purum 99%), used as diols for polyester synthesis, were purchased from Sigma–Aldrich Chemical Co (Chemie GmbH). All other materials and solvents used were of analytical grade. Solid-state polycondensation (SSP) was subsequently applied to produce polymers of high molecular weight. The reaction path for the synthesis of the polyesters is shown in Figure 1.

The main compound, 2,5-furan dicarboxylic acid (97% purity), was purchased from Sigma-Aldrich Chemical Co (Chemie GmbH, Steinheim, Germany). Tetrabutyltitanate (TBT) catalyst of analytical grade and 1,4-butanediol of analytical grade, used in polyester synthesis, were purchased from Sigma-Aldrich Chemical Co (Chemie GmbH, Steinheim, Germany). All other materials and solvents used were of analytical grade. Solid-state polycondensation (SSP) was subsequently applied to produce polymers of high molecular weight.
High-molecular-weight poly(butylene 2,5-furandicarboxylate) (PBF) was synthesized by applying melt polycondensation following the general procedure described in our previous study [21 (link)]. PET, PPT, and PBN were also prepared, as described in our previous studies, via the melt polycondensation procedure [39 (link),40 (link)]. PLA, with an average molecular weight of Mw = 20,000 Da and a polydispersity index of about 1.3, and poly(bisphenol A carbonate), with an average Mw of about 45,000 Da, were purchased from Sigma-Aldrich Chemical Co.