Synthesis and Ring-Opening Polymerization of Cyclic Butylene 2,5-Furandicarboxylate

Abstract

A new synthetic pathway for the polymerization of furan based polyesters is reported in this work. First, poly(butylene 2,5-furandicarboxylate) cyclic oligoesters (COEs) are chemically synthesized by semi-batch esterifi cation. The structure of the COEs is confi rmed by infrared spectroscopy, 1 H, and 13 C-NMR, while the molecular weight distribution of the COEs is determined by matrix-assisted laser desorption/ionization time of fl ight mass spectroscopy. The cyclic oligoesters are then successfully polymerized via ring-opening polymerization using tetrakis(2ethylhexyl)-titanate as catalyst. Differential scanning calorimetry and 1 H-NMR analysis unambiguously proves the formation of polymeric species. Both end-group analysis from 1 H-NMR spectrum and calculation through Flory-Fox equation give comparable estimates of the number average molecular weight: 5.8 × 10 3 g mol −1 and 7.8 × 10 3 g mol −1 , respectively. this approach. A still unexplored alternative route to produce this class of macromolecules consists in performing a ring-opening polymerization (ROP), exploiting the benefi ts of a living polymerization mechanism to overcome the typical polycondensation limits. In addition, the ROP method would enable a more precise control of the molecular weight and structure of the synthesized polymer and therefore of the material properties. [ 22,23 ] A ROP strategy is applied for the very fi rst time to the polymerization of furan based polymers. To pursue this strategy, a viable synthesis of the cyclic precursors must be envisioned and developed, and the ring-opening polymerization of these latter has to be proved. In short, the aim of this work is to explore the possibility to apply to furan-based polyesters a synthetic pathway similar to the one successfully developed for the production of polylactic acid, which is actually well-established also at industrial scale. [ 24,25 ] Accordingly, herein we present for the fi rst time the chemical synthesis of cyclic oligomers of butylene-2,5-furandicarboxylate and their successful polymerization into polybutylene 2,5-furanoate (PBF) by ROP. The proposed synthetic pathway could be generalized in the future to other furan-based copolymers, such as D. Pfi ster et al.

Blocky poly(ɛ‐caprolactone‐co‐butylene 2,5‐furandicarboxylate) copolyesters via enzymatic ring opening polymerization

“…1 H and C NMR spectra were recorded on a Bruker AMX‐300 spectrometer at 25 °C, operating at 300.1 and 75.5 MHz, respectively. Samples were dissolved either in deuterated chloroform (CDCl 3 ) or in a 1:8 mixture of trifluoroacetic acid and CDCl 3 , and spectra were internally referenced to tetramethylsilane.…”

“…Samples were dissolved either in deuterated chloroform (CDCl 3 ) or in a 1:8 mixture of trifluoroacetic acid and CDCl 3 , and spectra were internally referenced to tetramethylsilane. About 10 and 50 mg of sample in 1 mL of solvent were used for 1 H and C NMR, respectively. Sixty‐four scans were recorded for 1 H and between 1,000 and 10,000 scans for C NMR.…”

“…About 10 and 50 mg of sample in 1 mL of solvent were used for 1 H and C NMR, respectively. Sixty‐four scans were recorded for 1 H and between 1,000 and 10,000 scans for C NMR. High‐performance liquid chromatography was performed at 25 °C in a Waters apparatus equipped with a UV detector of Applied Biosystems operating at a wavelength of 254 nm, and a Scharlau Science column (Si60, 5 μm; 250 × 4.6 mm).…”

“…PEF and PBF are usually prepared by polycondensation of FDCA or its dimethyl ester (FDCA‐Me 2 ) with ethylene glycol and 1,4‐butanediol (BD), respectively . However the access to cyclic (alkylene 2,5‐furandicarboxylate) oligomers [ c (EF) n and c (BF) n ] recently afforded by chemical synthesis has opened the ROP route toward the preparation of these polyesters . Additionally, aromatic copolyesters made of butylene furanoate (BF) and butylene terephthalate (BT), as well as aromatic‐aliphatic copolyesters made from BF and butylene succinate (BS) have been prepared by ROP in good yields with pretty high molecular weights.…”

Advances in polymer precursors and bio‐based polymers synthesized from 5‐hydroxymethylfurfural

“…The interest in polymers derived from HMF and its derivatives has been rapidly increasing not only due to the sustainability and rich chemistry of HMF, but also due to the unique properties of these polymers. Currently, the preparation of HMF derivatives‐based polymers are mainly performed via chemical approaches . Enzymatic catalysis routes have been recently evaluated as well .…”