Efficient microwave-assisted synthesis of 5-hydroxymethylfurfural from concentrated aqueous fructose

Studies on the HCl-catalysed microwave-assisted dehydration of highly concentrated aqueous fructose (27 wt %) to 5-hydroxymethylfurfural (HMF) revealed a significant increase in the fructose conversion rate over the conventional heated systems. Water, being the most benign solvent and therefore ideal for green and sustainable chemistry, normally is a poor solvent for the dehydration process resulting in low HMF selectivities and yields. However, reaction at 200 °C with microwave irradiation with a short reaction time of only 1 s resulted in good HMF selectivity of 63% and fructose conversion of 52%, while prolonged irradiation for 60 s (or more) resulted in nearly full fructose conversion (95%) but lower HMF yield (53%). Decreasing the fructose concentration significantly improved the HMF selectivity, but possibly made the production route less attractive from an industrial point of view due to the resultant low throughput.

On the same wavelength: 5-Hydroxymethylfurfural—a promising platform compound for sustainable chemical production—was synthesised from highly concentrated fructose in acidic water media by employing microwaves, which significantly increased conversion rates and resulted in highest yield compared to conventional methods.Figure optionsDownload as PowerPoint slide