This study focused on maximizing yields of oligomeric and monomeric products while minimizing coke formation in the depolymerization of lignin from an organosolv medium. A design of experiments (DoE) with temperature, time, and ethanol‐water ratio as factors was established and tested. Optimized reaction conditions were found at 185.4°C with 7.5 wt% sodium hydroxide as catalyst, an ethanol‐water ratio of 48.6% (v/v), and a residence time of 30 minutes. With these optimized parameters, maximum monomer and oligomer yields of 9.4 wt% and 86.2 wt% and minimized coke formation of 0.5 wt% were achieved. The oligomeric and monomeric products were characterized by GPC, GC‐MS, and OH‐group determination (Folin‐Ciocalteu).

More wood for technical valorization is to be expected in Europe over the coming years, due to climate change and the bark beetle. To further independence from fossil-fuel resources a novel approach to the base-catalyzed depolymerization (BCD) of organosolv lignin into monomers and oligomers, while maximizing yields and minimizing coke formation, was scaled up in a theoretical wood-based biorefinery with a yearly input of 40 000 t of wood chips. Other process steps were modeled from the literature. A novel work-up approach was evaluated under laboratory conditions, implemented, and compared with a simulation-based pervaporation technique. The life-cycle assessment (LCA) showed that the biorefinery provided a significantly lower global warming potential (GWP) (excluding biogenic carbon) than its fossil counterparts. Moreover, the majority of impacts on the other midpoint categories was also smaller than for the fossil reference. However, after allocating the GWPs, it was evident that subsequent conversion of the C6 fraction to value-added products is necessary for optimal results. The discounted cash flow analyses for the biorefinery setups (40 to 400 kt year -1 ) showed that they were not profitable with prices based on fossil references. However, when using higher prices/t from the literature, such as €1615 for monomers, €2000 for oligomers, and €510 for C6 sugars, a positive net present value could be reached at

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Carbon capture and utilization (CCU) technologies support future energy and climate transition goals by recycling carbon dioxide (CO2) emissions. The use of biogenic CO2 from renewable sources, is an avenue for the production of fully renewable products. Fossil-based materials can potentially be replaced in the long term while allowing for the use of so called “waste” streams. To foster the development of a circular economy more insights need to be gained on the life cycle impact of CCU technologies. This study analyzed a CCU process chain, with focus on the utilization of volatile renewable electricity and biogenic CO2. We performed a cradle-to-gate life cycle assessment, evaluating various environmental impact categories (CML 2001 methodology) and primary energy demand (PED) with GaBi LCA software by sphera®. The targeted olefin is ethylene oxide (C2H4O), which is a crucial intermediate chemical for the production of various synthetic materials, such as polyethylene terephthalate (PET). As functional unit, 1 kg ethylene oxide was chosen. In the novel process at first ethylene (C2H4) and hydrogen peroxide (H2O2) are produced from water and CO2via an electrocatalytic process (Power-to-X process). In a second step, the two intermediates are synthesized to ethylene oxide. The theoretical implementation of a medium-scale process under average European conditions was considered in 12 scenarios that differed in energy supply and CO2 source. Sensitivity analyses were conducted to evaluate the influence of the energy and resource efficiencies of the production steps. The process was compared to its fossil benchmark, an existing conventional EO production chain. Concerning the global warming potential (GWP), negative emissions of up to −0.5 kg CO2 eq./kg product were calculated under optimized process conditions regarding energy and conversion efficiency and using biogenic CO2. In contrast, the GWP exceeded the fossil benchmark when the European grid mix was applied. The PED of 87 MJ/kg product under optimized conditions is comparable to that of other Power-to-X processes, but is high compared to fossil-based ethylene oxide. Based on the results we conclude that the energy efficiency of the electrocatalytic cell and renewable energy as input are the main levers to achieve a low environmental impact.