Two-step production of a furfural-derived biosolvent in a single reactor: an economic and life cycle assessment study

Abstract

In this study, we investigated the credentials of furfural as a building block for producing 5-methyl-1-(tetrahydrofuran-2-yl)hexan-3-one (THF-ALD-1), a prospective biosolvent. The process consists of two steps: (1) aldol condensation–crotonisation of furfural with methyl isobutyl ketone (MIBK) to generate (E)-1-(furan-2-yl)-5-methylhex-1-en-3-one (ALD-1) and (2) selective hydrogenation of ALD-1 to THF-ALD-1 in MIBK. We conducted a comparative techno-economic analysis (TEA) and life cycle assessment (LCA) to evaluate the potential benefits of process intensification in a single reactor using a bifunctional 5%Pd/Al₂O₃ catalyst compared to a two-reactor process employing two catalysts—Al₂O₃ for the aldol condensation–crotonisation step and 5%Pd/Al₂O₃ for ALD-1 hydrogenation. A sensitivity analysis was performed to identify the key contributing factors and propose levers to reduce the cost and environmental footprint of THF-ALD-1 production. Our study demonstrates that a single-reactor process can offer an 11% and 7.5% reduction in the full manufacturing cost and minimum selling point, respectively, alongside reductions in environmental impact in most categories, with statistically significant improvements observed for acidification potential (21%), photochemical oxidant creation potential (22%), freshwater ecotoxicity potential (19%), and terrestrial ecotoxicity potential (46%). Directional trends toward lower impacts were also observed in the remaining categories. The furfural and MIBK market price fluctuations, overall yield, MIBK/furfural molar ratio, and the number of Pd/Al₂O₃ catalyst regeneration cycles are critical levers that influence fresh Pd demand, waste generation, and heat requirements for distillation. Optimisation of these parameters could yield potential cost benefits up to 20% for each process and mitigate by 32–36% the global warming potential, non-renewable energy use, and abiotic and ozone depletion potential, with full statistical significance according to Monte Carlo analysis.