Search

In this work, a novel family of α,ω-diene carbonate monomers was synthesized via the alkoxy carbonylation reaction of bis(hydroxymethyl)furan (BHMF) with dialkyl carbonates (DACs) of varying chain lengths, containing terminal olefins, in the presence of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD). These monomers were then subjected to acyclic diene metathesis (ADMET) polymerization with seven different ruthenium catalysts. The second-generation Hoveyda–Grubbs catalyst proved to be the most effective, yielding furan-based polycarbonates with molecular weights (Mn) up to 19 kDa. The resulting bio-based polymers exhibited thermal degradation temperatures (Td5%) ranging from 156 °C to 244 °C and glass transition temperatures (Tg) from −8 °C to −36 °C. NMR studies confirmed their polymeric structures and provided insights into the polymers organization, which influenced their properties. These novel polycarbonates were then compared to previously reported polyesters and polyethers derived from similar furan-based α,ω-diene monomers. Additionally, for the first time, co-polymerization studies were conducted on three families of furan-based α,ω-diene monomers—ester, ether, and carbonate—revealing the effect of incorporating different functional groups on the properties of the resulting materials. This unprecedented comparison and co-polymerization reactions highlight the versatility of furan-based monomers, but also underscores the possibility to expand their application in creating tailored bio-based materials for diverse applications. [ABSTRACT FROM AUTHOR]

Since 5-(hydroxymethyl)furfural (HMF) has been labelled as the "sleeping giant" of the bio-based platform-chemical realm, numerous investigations have been devoted to the exploitation of this versatile molecule and its endless chemical transformations into novel monomers for producing bio-based polymers. However, beyond 2,5-furandicarboxylic acid (2,5-FDCA), little attention has been devoted to key aspects that deserve being addressed before bringing forward other HMF-derivatives into the bio-based plastic market, i.e., procedures, scaling-up of the syntheses, products' purification, physical–thermal properties, and above all green metrics (sustainability/greenness of procedures). This critical review focuses on the most investigated derivatives of HMF beyond 2,5-FDCA, assessing their exploitation as monomers for bio-based polymers. HMF-derived compounds have been classified according to their functionalities, i.e., aldehyde-, diol-, polyol-, amine-, acid-, ester-, carbonate-, acrylate-, and epoxy-based monomers. The related synthetic approaches are discussed, evaluating the sustainability of the procedures reported so far, based on green metrics such as the environmental factor (E-factor) and the process mass intensity (PMI). For each family of HMF derivatives, their use as monomers for the synthesis of bio-based polymers has been addressed, taking into consideration the efficiency of the polymerisation reactions, the physical–chemical and thermal properties of the resulting bio-based polymers, as well as their biodegradability if applicable. The overall picture that emerges is that much has been achieved for the synthesis of furan monomers; however, many obstacles still need to be overcome prior to massively introducing these compounds into the bio-based plastic market. Hopefully, the data reported in this review will shed light on the goals achieved so far, and on some critical issues that must still be tackled in the short- or medium-term for a more sustainable and however efficient industrial process. [ABSTRACT FROM AUTHOR]

In this work two synthetic approaches to introduce nitrile moieties into bio‐based derived furanic compounds were investigated, i. e. dehydration of aldoximes and Knoevenagel condensation. Both methodologies have been first tested and optimized on furfural and thus exploited on 5‐hydroxymethyl‐2‐furfural (HMF) and 5,5'‐oxy(bismethylene)‐2‐furaldehyde (OBMF). The syntheses of furfural, HMF and OBMF aldoximes were efficiently conducted (also in large scale) under mild reaction conditions and short reaction time. The subsequent dehydration to nitrile furanic compounds was carried out in the presence of catalytic amount of copper acetate monohydrate. Furthermore, Knoevenagel condensations were performed on furfural, HMF and OBMF with different Activated Methylene Group compounds, using for the first‐time dimethyl carbonate as the reaction media. Most of the resulting products were isolated as pure via simple liquid‐liquid extraction in good to excellent yields. Future applications of these compounds might include aldoxime reduction into amine furanics ‐ herein also preliminary investigated ‐ and hydrolysis of the nitrile derivatives in the related carboxylic acid (or ester) furanics. All these products are interesting monomers for the preparation of bio‐based polymers. [ABSTRACT FROM AUTHOR]

The present research article delves into the preparation of a new class of bio‐based polyesters from α,ω‐diene furandicarboxylate monomers. In particular, it exploits the use of acyclic diene metathesis polymerisation (ADMET) on 2,5‐furandicarboxylic acid (FDCA)‐derived compounds. First, a library of furan‐based α,ω‐diene monomers was prepared via acid‐ or base‐catalyzed transesterification of 2,5‐furandicarboxylic acid dimethyl ester (FDME) with commercially available alcohols incorporating terminal olefins, i. e. allyl alcohol, but‐3‐en‐1‐ol, hex‐5‐en‐1‐ol and dec‐9‐en‐1‐ol. Then, the novel monomers were subjected to ADMET polymerisation employing different catalysts and reaction conditions. Interestingly, first‐generation Grubbs catalyst was found to be the best promoter for ADMET polymerisation. This catalyst allowed the preparation of a new family of bio‐based polyesters with molecular weights up to 26.4 kDa, with good thermal stability, and adaptable cis‐trans conformations. Results also revealed that the monomer structure had a direct impact on the polymerisation efficiency and the resulting thermal properties. The effect of green bio‐based solvents such as Cyrene™, dimethyl isosorbide (DMI) and γ‐valerolactone (GVL) on the polymerisation process was also studied. Data collected showed that the solvent concentration influenced both the yield and length of polymers formed. Furthermore, some co‐polymerisation experiments were conducted; the successful integration of different monomers in the resulting copolymer was shown to affect the glass transition temperature (Tg) of the resulting materials. [ABSTRACT FROM AUTHOR]

This study focuses on the synthesis of fully renewable polycarbonates (PCs) starting from cellulose‐based platform molecules levoglucosenone (LGO) and 2,5‐bis(hydroxymethyl)furan (BHMF). These unique bio‐based PCs are obtained through the reaction of a citronellol‐containing triol (Triol‐citro) derived from LGO, with a dimethyl carbonate derivative of BHMF (BHMF‐DC). Solvent‐free polymerizations are targeted to minimize waste generation and promote an eco‐friendly approach with a favorable environmental factor (E‐factor). The choice of metal catalyst during polymerization significantly influences the polymer properties, resulting in high molecular weight (up to 755 kDa) when Na2CO3 is employed as an inexpensive catalyst. Characterization using nuclear magnetic resonance confirms the successful incorporation of the furan ring and the retention of the terminal double bond of the citronellol pendant chain. Furthermore, under UV irradiation, the presence of both citronellol and furanic moieties induces singular structural changes, triggering the formation of three distinct structures within the polymer network, a phenomenon herein occurs for the first time in this type of polymer. These findings pave the way to new functional materials prepared from renewable monomers with tunable properties. [ABSTRACT FROM AUTHOR]