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Demonstration of solvent and resin production from lignocellulosic biomass via the platform chemical levulinic acid

Periodic Reporting for period 4 - GreenSolRes (Demonstration of solvent and resin production from lignocellulosic biomass via the platform chemical levulinic acid)

Reporting period: 2020-09-01 to 2021-12-31

The need to establish economically and environmentally sustainable large-scale systems for the conversion of biomass to building blocks for the chemical industry is becoming increasingly urgent regarding climate change and shrinking oil reservoirs. The overall objective of GreenSolRes is to demonstrate the competitiveness of the levulinic acid (LVA) value chain in terms of costs, environmental impacts, and technical performance. Lignocellulosic biomass is converted in a robust and low-impact process to platform chemical LVA, which is subsequently reduced to γ-valerolactone (GVL), 1-methyl-1,4-butanediol (MeBDO) and 2-methyltetrahydrofuran (2-MTHF). The LVA-derivatives are applied as solvents or as building blocks in different polymers like polyurethanes, polyesters and polyethers and then formulated to bio-based adhesives. . These bio-based chemicals have similar to superior eco-toxicity properties compared to the established fossil-based solvents. Compared to their fossil-based C4-counterparts, LVA and related products have a high greenhouse gas (GHG) avoidance of up to 80%. They provide an additional value to society via better health and safety properties.
NGP2-biorefinery of RWTH has been retrofitted and commissioned for LVA production. Several campaigns in an integrated multi-reactor mode were successful. The LVA separation and purification strategy was developed. Systematic investigation of the critical steps led to the development of a process for the production of purified LVA at 50 kta scale with valorisation of solid residues.
In parallel, a second route for the transformation of furfural to LVA and esters and its consequent hydrogenation was examined. A successful heterogeneous gas-phase hydrogenation of ethyl levulinate to GVL has been performed in continuous mode from small scale to kg-scale.
For the homogeneous hydrogenation of LVA, molecular catalysts were evaluated. Consequently, tailored molecular catalyst systems enabled a selective hydrogenation. A scalable synthetic protocol for the preparation of selected catalyst has been developed and application testing has been performed. The comprehensive evaluation demonstrated favourable performance indicators for the 2-step process involving separation of metal-catalysed hydrogenation to GVL and MeBDO from the acid-catalysed cyclisation of MeBDO to 2-MTHF. To increase activity and stability of the utilised catalyst systems, structural variations of the recently established ligands were performed. The catalyst could be successfully recycled.
For application & development of hydrogenation intermediates, technical analysis indicated 2-MTHF as a replacement for fossil-based solvent THF. Further improvements in manufacturing of 2-MTHF led to high quality polymers that demonstrated a potential use in conventional polyurethane adhesives. In parallel, MeBDO polyesters were synthesised, screened, scaled up and tested for adhesive use. Results indicate promising novel bio-based materials with superior performance and properties compared to standard fossil-based alternatives. It is concluded that MeBDO can be beneficially utilised as building block for polyurethanes and specifically reactive polyurethane hotmelt adhesives (PURHM). A market start is promising for PURHM adhesives in high value adhesive markets. Reactive two component (2C) epoxy adhesives with the GVL-derivative have been developed.
For the risk and safety assessment of bio-based chemicals and their respective fossil-based benchmarks, extensive literature review and a stepwise test strategy was carried out to gather data on the physical-chemical properties, human toxicity, eco-toxicity (hazard assessment) and environmental fate (biodegradation, bioaccumulation). Life-cycle analysis indicated 30-80% reduction in global warming impacts with bio-based chemicals in comparison to their fossil-based counterparts in various scenarios.
Dissemination to target audiences including science and the general public took place via scientific publications, international conferences, seminars and workshops, a project website ( as well as social media channels like Linkedin. Exploitation first focussed on patenting the intellectual property before a stakeholder workshop was held in spring 2021 to present the achieved results to an industrial community and gain interest in further investments. Specific topics like low cost feedstock (waste wood, and residues from food industry) and the further investment in upscaling were focussed in interviews with representatives of industry. The finalized engineering concept including mass and energy balances of a 50 KT plant form the basis to proceed with industrial investors towards upscaling the process into a first commercial plant. The increase of production volumes will be a prerequisite to open markets for envisaged bio-based adhesives and solvents contributing to reduce emissions responsible for climate change and increase competitiveness of European industry.
LVA production at NGP2 in a technical environment is a key step towards the scheduled economic and carbon neutral production of a highly significant platform chemical. As an impactful outcome of the process design, a new tailored purification strategy was developed and implemented. Gathered data lead to a complete engineering package of 50kta LVA plant. The cost of manufacture of LVA is estimated as 2 €/kg (base case) that can come down to ca. 1 €/kg after valorisation of side products. For the subsequent hydrogenation of LVA to the target products, a molecular catalyst was developed. The tailoring of the catalysts’ lead structure in a way to feature only high-boiling components has expanded the limits of molecular catalysis towards the level of heterogeneous catalysis. The homogenous catalyst system developed within the project is the only system capable of hydrogenation of LVA via GVL to MeBDO. Knowledge has been obtained on the production of kg amounts of Triphos ligands, on the scale-up of ligands & hydrogenation products of LVA. In parallel, route 2 to produce GVL via furfural using heterogenous catalyst could be optimised and successfully implemented at kg scale. Further up-scale of the developed process to existing industrial assets is possible. Bio-based GVL has never been produced on a large industrial scale.
Novel polymers with incorporation of 2-MTHF or MeBDO were developed. 2-MTHF can be directly used as solvent or in polymers for the formulation of adhesives. 2-MTHF-based polyethers represent promising bio-based alternatives to existing commercial polyether polyols providing additional performance features. Encouraging results could be obtained with MeBDO-based polymers resulting in novel bio-based polyols broadening up the overall bio-based formulation toolbox for the coatings, adhesives, sealants & elastomers market. Finally, GVL derivatives also appear very promising for different reactive adhesive applications. These bio-based products, based on the LVA platform, have a better technical performance and similar or improved eco-toxicity properties compared to the established fossil-based counterparts. LCA results of the GreenSolRes products indicate favourable reduction in GHG emissions.
System boundaries in Life Cycle Assessment
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Development and testing of bio-based adhesives
Scheme of GreenSolRes project
Extraction of Levulinic acid at demo-plant
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