High‐Yielding Synthesis of 5‐(alkoxymethyl)furfurals from Biomass‐Derived 5‐(halomethyl)furfural (X=Cl, Br)

Industrial Routes from Sugars and Biomass to CMF and Other 5-(Halomethyl)furfurals

The synthesis of 5-(halomethyl)furfurals (XMFs, X=F, Cl, Br, I), including 5-(chloromethyl)furfural (CMF), 5-(bromomethyl)furfural (BMF), 5-(iodomethyl)furfural (IMF), and 5-(fluoromethyl)furfural (FMF), from biomass represents a pivotal advancement in renewable chemistry and engineering. Harnessing waste biomass as a raw material offers a sustainable alternative to fossil-based resources, mitigating environmental degradation and addressing pressing energy needs. CMF and BMF, characterized by their enhanced stability over the hydroxyl analog, 5-(hydroxymethyl)furfural (HMF), exhibit promise as renewable building blocks for scale-up and commercialization. The surge in research interest, particularly from 2010 to 2024, reflects a growing recognition of XMFs' potential as novel platform chemicals. This review highlights the evolution of XMF synthesis methods, focusing on their transformation from saccharides and lignocellulosic biomass. Mechanistic insights and experimental setups are scrutinized for industrial feasibility and scalability, shedding light on technical challenges and avenues for further research. The analysis underscores the burgeoning significance of XMFs in the transition towards sustainable chemical production, emphasizing the importance of process optimization and mechanistic understanding for commercial deployment.

Extraction of 5-Hydroxymethylfurfural and Furfural in Aqueous Biphasic Systems: A COSMO-RS Guided Approach to Greener Solvent Selection

5-Hydroxymethylfurfural (HMF) and furfural (Fur) are promising biobased platform chemicals, derived from the dehydration of carbohydrate feedstocks, normally conducted in an aqueous phase. Plagued by side-reactions in such phase, such as the rehydration to levulinic acid (LA) and formic acid (FA) or self-condensation to humins, HMF and Fur necessitates diversification from monophasic aqueous reaction systems toward biphasic systems to mitigate undesired side-reactions. Here, a methodology based on the COnductor-like Screening MOdel for Real Solvents (COSMO-RS) method was used to screen solvent candidates based on the predicted partition coefficients (Ki). Hansen solubility parameters in conjunction with excess thermodynamic quantities determined by COSMO-RS were employed to assess solvent compatibility. Experimental validation of the COSMO-RS values highlighted only minor deviations from the predictions with root-mean-square-error (RMSE) values of HMF and Fur at 0.76 and 5.32, respectively, at 298 K. The combined effort suggested cyclohexanone, isophorone, and methyl isobutyl ketone (MIBK) as the best candidates. Finally, extraction solvent reuse demonstrated cyclohexanone suitability for HMF extraction with KHMF of 3.66 and MIBK for Fur with KFur 7.80 with consistent partitioning across four total runs. Both solvents are classified as recommended by the CHEM21 solvent selection guide, hence adding to the sustainability of the process.