This review represents an overview of the status quo of the furan-based monomers and related bio-based polymers, highlighting key challenges for scaling from lab to pre-industrial levels.
A simple procedure for the one-pot synthesis of 2,5-furandicarboxylic acid dimethyl ester (FDME) from galactaric (mucic) acid via dimethyl carbonate (DMC) chemistry is presented. The compound was isolated as a white powder in 70% yield.
9 September 2022 in Organic Process Research & Development
5-Hydroxymethylfurfural (HMF) is a bio-based platform chemical that can be used as a building block to produce several compounds with diverse applications. Even though HMF synthesis holds promise for a greener future, the current state of technology and the high production cost limit its competitiveness on an industrial scale. In this prospect, we have developed a multigram-scale procedure for HMF by reacting d-fructose with Purolite CT275DR-an acidic resin-in a dimethyl carbonate (DMC)/tetraethyl ammonium bromide (TEAB) biphasic system. Reactions performed in an autoclave for 2 h at 110 °C using up to 40 gram of d-fructose resulted in an overall HMF yield of 70%. HMF was purified by a custom-made procedure leading to ca 50% of the pure crystalline product; meanwhile, the residual HMF-rich oil was directly reduced to bis(hydroxymethyl)furan (BHMF). Green metrics and the Ecoscale algorithm were used to evaluate the sustainability of the herein-proposed procedure in comparison with previously reported works.
Dimethyl isosorbide (DMI) is a well-known bio-based green replacement for conventional dipolar solvents such as dimethyl sulfoxide and dimethylformamide. The synthesis of DMI mainly relies on the etherification of the bio-based platform chemical isosorbide in the presence of basic or acid catalysts and by employing different alkylating agents. Among them, dimethyl carbonate (DMC) is considered one of the most promising for its good biodegradability and low toxicity. In this work, we report on a comprehensive investigation on high yielding methylation of isosorbide via DMC chemistry promoted by nitrogen organocatalyst N-methyl pyrrolidine (NMPy). Reaction conditions were optimized and then efficiently applied for the methylation of isosorbide epimers, isoidide and isomannide, and for some preliminary scale-up tests (up to 10 grams of isosorbide). The purification of DMI from the reaction mixture was achieved by both column chromatography and distillation at reduced pressure. NMPy demonstrated to be an excellent catalyst also for the one-pot conversion of D-sorbitol into DMI. Furthermore, for the first time, all seven methyl and methoxycarbonyl intermediates observed in the etherification of isosorbide were synthetised, isolated and fully characterised. This has provided an insight on the concurrent reaction pathways leading to DMI and on the role played by NMPy in the methylation of isosorbide. Finally, the reaction mechanisms for the methylation, methoxycarbonylation and decarboxylation promoted by NMPy partaking in the conversion of isosorbide into DMI via DMC chemistry have been proposed.
Cellulose-derived photocrosslinkable polycarbonates with renewable citronellol pendant chains were synthesised via polycondensation of Triol-citro, a levoglucosenone-based triol monomer, and dimethoxycarbonyl isosorbide.