SUSTAINABLE SYNTHESIS AND POLYCONDENSATION OF LEVOGLUCOSENONE- CYRENE TM -BASED BICYCLIC DIOL MONOMER: AN ACCESS TO RENEWABLE POLYESTERS Florian Diot-Néant, Louis Mouterde, Sami Fadlallah, Stephen Miller, Florent Allais To cite this version: Florian Diot-Néant, Louis Mouterde, Sami Fadlallah, Stephen Miller, Florent Allais. SUSTAINABLE SYNTHESIS AND POLYCONDENSATION OF LEVOGLUCOSENONE- CYRENE TM -BASED BICYCLIC DIOL MONOMER: AN ACCESS TO RENEWABLE POLYESTERS. ChemSusChem, ChemPubSoc Europe/Wiley, 2020, 10.1002/cssc.202000680. hal-02777287 HAL Id: hal-02777287 https://hal.archives-ouvertes.fr/hal-02777287 Submitted on 4 Jun 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. SUSTAINABLE SYNTHESIS AND POLYCONDENSATION OF LEVOGLUCOSENONE- CYRENETM-BASED BICYCLIC DIOL MONOMER: AN ACCESS TO RENEWABLE POLYESTERS Florian Diot-Néant+,a, b Louis Mouterde+,*a Sami Fadlallah,a Stephen A. Miller,*b and Florent Allais*a, c a URD Agro-Biotechnologies Industrielles (ABI), CEBB, AgroParisTech 51110, Pomacle (France) b The George and Josephine Butler Laboratory for Polymer Research Department of Chemistry University of Florida Gainesville, FL 32611-7200 (USA) c Department of Chemistry University of Florida Gainesville, FL 32611-7200 (USA) +These authors contributed equally to this work Abstract The already-reported, low-yielding, and non-sustainable Et3Nmediated homocoupling of levoglucosenone (LGO) into the corresponding LGO-Cyrene™ diketone has been revisited and greened-up. The use of methanol as both a renewable solvent and catalyst and K2CO3 as a safe inorganic base improved the reaction significantly with regards to yield, purification, and green aspects. LGO-Cyrene™ was then subjected to a one-pot, H2O2-mediated Baeyer–Villiger oxidation/rearrangement followed by an acidic hydrolysis to produce a new sterically hindered bicyclic monomer, 2H-HBO-HBO. This diol was further polymerized in bulk with diacyl chlorides to access new promising renewable polyesters that exhibit glass transition temperatures (Tg) from -1 to 81 °C and a good thermostability with a temperature at which 50% of the mass is lost (Td50%) of 349–406 °C. Keywords: biomass, dimerization, oxidation, polymers, synthesis design Background The urgent need of sustainable and safe alternatives to replace depleting fossil1 resources and solve environmental issues such as the “Plastic Continents” in the Pacific Ocean2 and the severe changes caused by Anthropocene’s3 polluting gas has driven investigations and creations of bio-synthon databases4 to substitute the current petroleum-based molecules. The production of the well-known lactic acid from sugar fermentation is a good example of white biotechnology applied to biomass for the production of bio-based monomers. The corresponding material, poly(lactic acid) (PLA), has been commercialized for years and is largely used as the main material for cold beverage cups. Moreover, PLA’s low glass transition temperature (Tg of 55 °C) compared to other commodity plastics, such as poly(ethylene terephthalate), prohibits its utilization at high temperature. Still, PLA remains a good alternative for moderate temperature applications. Scheme 2-1. Examples of bio-based synthons Scheme 2-2. Transformation of Cellulose into CyreneTM A few other examples of bio-based molecules used as building blocks in Polymer Science have been described in the literature, including itaconic acid,4 succinic acid,4 angelica lactone,5 levulinic acid, a precursor to methylene-γ-valerolactone,6,7 and levoglucosenone (LGO),8,9 a promising α,β-unsaturated cyclic ketone (Scheme 2-1). The high potential of LGO as both a building block and a precursor of CyreneTM, a green aprotic polar solvent, has caught the attention of a few research groups and companies. In 2008 Circa developed the FuracellTM technology,10 a scalable process that allows LGO production from cellulose-based feedstocks, such as bagasse and sawdust, and its subsequent hydrogenation to produce CyreneTM (Scheme 2-2).11 Apart from a few works such as the reduction of the ketone moiety of Cyrene™ and its subsequent acrylation proposed by Saito and co-workers12 to form the corresponding acrylate and polyacrylate, the use of LGO and CyreneTM in material Scheme 2-3. Synthesis of poly(M-THP-2H-HBO) from 2H-HBO Scheme 2-4. Green synthesis of HBO from LGO science appears limited. Recently, we reported the synthesis of renewable acrylate monomers with (S)-γ-hydroxymethyl-α,β-butenolide (HBO), a bio-based molecule derived from LGO, to produce high-Tg biobased polymers with post-polymerization possibilities (Scheme 2-3).13 Over the last decades, several processes involving either chemical14,15 or chemo-enzymatic16 conditions have been proposed to synthetize HBO from LGO through Baeyer-Villiger oxidations. For example, in 201817 we reported the organic solvent-free oxidation of LGO into HBO with 30% aqueous H2O2 without the presence of any catalyst (Scheme 2-4). Besides its interest as a precursor for the synthesis of such a bio-based acrylate, HBO could also be transformed into an AB- or AA’-type monomer if another alcohol or acid function could be added to its structure. Scheme 2-5. Oligomerization of LGO by Stevenson and co-workers18 In 1982, Stevenson and co-workers18 reported the formation of LGO-CyreneTM in 8% yield when LGO was heated at 80-85 °C in the presence of triethylamine (Scheme 2- 5). In 1995, Peters and coworkers19 described the self-condensation of LGO as a side reaction whenever LGO was highly concentrated in the presence of a base and the dimer LGO-CyreneTM was isolated in 32% yield. To the best of our knowledge, no further optimizations or chemical transformations were carried out to take advantage of this promising molecule that offers a great playground for chemists due to its two ketone moieties. Building on our experience with LGO upgrading through sustainable synthetic processes,16,17,20,21,22 we decided to investigate the implementation of the aforementioned Baeyer-Villiger-based strategy17 to LGO-CyreneTM to access the corresponding 2HHBO- HBO as a new bio-based AA’-type diol monomer with the aim to produce renewable polyesters with the HBO motif (Scheme 2-6). Scheme 2-6. Syntehsis of 2H-HBO-HBO polyesters from LGO Experimental Chemicals and regeants Levoglucosenone was graciously provided by the Circa Group. Potassium carbonate 99% (Acros), hydrogen peroxide 30% (Fischer), diethyl succinate 98% (Alpha Aesar), malonyl chloride 97% (Sigma Aldrich), succinyl chloride 95% (Sigma Aldrich), adipoyl chloride 98% (Sigma Aldrich), glutaryl chloride 97% (Sigma Aldrich), terephthaloyl chloride >99% flakes (Sigma Aldrich) were used without further purification unless mentioned. NMR solvents including deuterated chloroform, deuterated methanol, and deuterated dimethyl sulfoxide were purchased from Cambridge Isotopes Laboratories. Characterization Nuclear Magnetic Resonance (NMR) spectroscopy 1 H NMR spectra of samples were recorded at 300 MHz (CDCl3, CD3OD, DMSO-d6 and 13 Acetone-d6 residual signal at 7.26, 3.31, 2.50 and 2.05 ppm respectively). C NMR spectra of samples were recorded at 75 MHz (CDCl3, CD3OD, DMSO-d6 and Acetone-d6 residual signal at 77.2, 49.0, 39.5 and 29.8, respectively). Chemical shifts are reported in parts per million (ppm). Coupling constants (J) are reported in Hertz (Hz). Multiplicities are reported using the following abbreviations: s, singlet; d, doublet; t, triplet; q, quartet; m, multiplet; br, broad. Thermogravimetric Analysis (TGA) TGA was performed under nitrogen with a TGA Q500 from TA Instruments. About 1-5 mg of each sample was equilibrated at 50 °C for 30 min. Then, the samples were heated at 10 °C/min from 50 °C to 500 °C. The reported values (Td5% and Td50%) represent the temperature at which 5% and 50% of the mass is lost, respectively. Differential Scanning Calorimetry (DSC) DSC thermograms were obtained with a DSC Q20 from TA Instruments. Typically, 5-10 mg of sample were weighed and charged into a sealed pan that passed through a heat- coolheat cycle at 10 °C/min. The temperature ranged from -80 °C to 100 °C. Gel Permeation Chromatography (GPC) GPC was performed at 60 °C using an Agilent Technologies 1260 Infinity Series liquid chromatography system with an internal differential refractive index detector, a viscometer detector, a laser, UV lamp and two PLgel columns (5μm MIXED-D 300x7.5mm) using 10mM Lithium Bromide (LiBr) in HPLC grade dimethylformamide (DMF) as the mobile phase at a flow of 1.0 mL/min. Calibration was performed with narrow dispersity Polystyrene Standards (Mw: 620, 1,320, 2,930, 4,730, 10,190, 19,650, 29,870, 75,000, 123,700 and 278,700 g.mol-1). The samples were prepared by solubilizing around 5 mg of material in 1 mL of the aforementioned solvent. Monomer synthesis Synthesis of (1S,1'S,2R,5R,5'R)-6,6',8,8'-tetraoxa[2,3'- bi(bicyclo[3.2.1]octan)]-2'-ene-4,4'-dione (LGO-Cyrene™) LGO (2.59 g, 2 mL, 20.5 mmol) was solubilized in methanol (2.2 mL) and 45 mg (0.3 mmol) of K2CO3 were added. The solution was stirred at room temperature until the precipitate hinders the stirring. The reaction was filtered to obtain an orange solid that could be engaged in the next step without further purification (2.56 g, 99% yield). 1 H NMR (DMSO-d6, 300 MHz): δH 2.17 (d, 1H, J = 17.0 Hz, H12), 3.09 (dd, 1H, J = 8.6 and 17.0 Hz, H12’), 3.38 (m, 1H, H7), 3.75 (m, 2H, H3 & H9), 3.90 (m, 1 H, H9’), 4.27 (m, 1H, H3’), 4.52 (m, 1H, H8), 5.10(s, 1H, H10), 5.27 (t, 1H, J = 4.5 Hz, H4), 5.45 (s, 1H, H2), 13 7.12 (dd, 1H, J = 1.2 & 5.0 Hz, H5).