The catalytic transformation of bio-derived compounds, specifically 5-hydroxymethyfurfural (HMF), into value-added chemicals may provide sustainable alternatives to crude oil and natural gas based products. HMF can be obtained from fructose and successfully converted to 2,5-diformylfuran (DFF) by an environmental-friendly organic electrosynthesis performed in an ElectraSyn reactor, using cost-effective and sustainable graphite (anode) and stainless steel (cathode) electrodes in an undivided cell, without the need for conventional precious metal electrodes. In this work, we perform the electrocatalysis of HMF using green solvents such as acetonitrile, γ-valerolactone, as well as PolarClean that is used in electrocatalysis for the first time. The reaction parameters, and the synergistic effects of the TEMPO catalyst and 2,6-lutidine base are explored both experimentally and through computation modelling. The molecular design and synthesis of a size-enlarged C3-symmetric tris-TEMPO catalyst are also performed to facilitate a sustainable reaction work-up via nanofiltration. The obtained performance is then compared with those obtained by heterogeneous TEMPO alternatives recovered via an external magnetic field and microfiltration. Results show that our new method of electrocatalytic oxidation of HMF to DFF can be achieved with excellent selectivity, good yield, and excellent catalyst recovery.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: Scheme 1, Figure 7 and the table of contents illustrations were created by Heno Hwang, scientific illustrator at King Abdullah University of Science and Technology (KAUST). This work was supported by Janos Bolyai Research Scholarship of the Hungarian Academy of Sciences (JK), the New National Excellence Program of the Ministry of Human Capacities, grant number ÚNKP-19-4-BME-415 (JK), and the Gedeon Richter's Talentum Foundation (PK). The research reported in this publication was supported by funding from KAUST.