Abstract
The production of fuels from renewable electricity and biomass is a promising route towards a closed carbon cycle economy. [1] Therefore, the direct electrochemical conversion of biomass-based platform chemicals such as 5-hydroxymethylfurfural (HMF) has gained increasing interest in recent years. It is known that HMF can be hydrogenated to fuels and fuel precursors such as 2,5-dimethylfurfural (DMF) and 2,5-dihydroxymethylfurfural (DHMF), whereas the competing electrohydrodimerization reaction was just recently reported. [2] This dimerization reaction yields the C12 product 5,5'-bis(hydroxymethyl)hydrofuroin (BHH), which is a precursor for jet or diesel fuel due to its optimal carbon chain length. Thus, we developed an approach towards evaluating the performance of different electrocatalysts for the electrohydrodimerization of HMF under various conditions in aqueous media. This goal was achieved, on the one hand, by adapting our screening technique - electrochemical real-time mass spectrometry (EC-RTMS) - for analyzing transient reaction processes and onset potentials for the product formation. On the other hand, an electrochemical flow reactor was established for performing steady-state electrolysis followed by product quantification using high-performance liquid chromatography (HPLC) and gas chromatography (GC). Different carbon-based materials showed high potent as electrocatalysts for the facile reduction of HMF to BHH.
References
[1] S. Palkovits, R. Palkovits, The Role of Electrochemistry in Future Dynamic Bio-Refineries: A Focus on (Non-)Kolbe Electrolysis, Chem. Ing. Tech., 91 (2019) 699-706.
[2] X.H. Chadderdon, D.J. Chadderdon, T. Pfennig, B.H. Shanks, W. Li, Paired electrocatalytic hydrogenation and oxidation of 5-(hydroxymethyl)furfural for efficient production of biomass-derived monomers, Green Chemistry, 21 (2019) 6210-6219.
Figure 1