Abstract: A continuous electrochemical process with integrated product separation has been developed for production of 2,5-furandicarboxylic acid (FDCA) by oxidation of 5-(hydroxymethyl)furfural (HMF) in aqueous alkaline media on non-noble Ni/NiOOH foam electrodes at ambient conditions. Initially, voltammetry studies were performed in both, acid and alkaline media, on various catalyst materials: Au, Au₃Pd₂, Pt, PbO₂, Ni/NiOOH and graphite. Preparative electrolysis was performed on Au, Au₃Pd₂, Pt, PbO₂, Ni/NiOOH electrodes in a divided glass cell and Ni/NiOOH showed the best performance with an FDCA yield of ≈ 90% and a Faradaic efficiency of ≈ 80%. The electrolysis conditions were then optimized to industrially relevant conditions in a filter-press type flow reactor with Ni/NiOOH foam anode. HMF concentrations as high as 10 wt% were converted to FDCA at pH 12 in a buffer free 0.1 M Na₂SO₄ electrolyte with continuous addition of NaOH to maintain constant pH. An FDCA separation yield up to 95% was achieved via pH shift crystallization. The electrolysis and FDCA separation results were used for the design and construction of a bench-scale system where continuous FDCA production, including integrated product separation, was tested and reported in this work. This publication for the first time presents a continuous electrochemical FDCA production system with integrated product separation at industrially relevant product concentrations, 10 wt% HMF, and utilizing non-noble electrode materials.

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Most fermentation products have a feedback inhibiting effect on the host organism. In situ product recovery (ISPR) can be a means to overcome this product inhibition in fermentations. Particles such as solvent impregnated resins or capsules can be valuable tools for product recovery based on extraction. To evaluate, which kind of particle will be feasible for a certain kind of fermentation product an evaluation is presented here. Furthermore, an assessment is made what the impact is of ISPR for enhancing productivities in relatively non-inhibiting (lactic acid), fairly inhibiting (phenol) and severely inhibiting (erythromycin) fermentation products. A process containing solvent impregnated resins or capsules is evaluated based on enhanced productivities and cost-effectiveness. It is shown that applying these particles inside a fermentor can result in a decrease in ±30% of total manufacturing costs for pharma-intermediate production.@en