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

Periodic Reporting for period 3 - GreenSolRes (Demonstration of solvent and resin production from lignocellulosic biomass via the platform chemical levulinic acid)

Reporting period: 2019-03-01 to 2020-08-31

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 LVA derivatives are applicable as well in the pharmaceutical sector. After successful demonstration, the project will prepare an optimized process design in full commercial scale enabling the planning of a first commercial plant. The bio-based chemicals are expected to have superior eco-toxicity and pharmacological 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 at least 70%. 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. First trial campaigns were successful. The LVA separation and purification strategy is developed. In parallel, a route 2 for the transformation of an alternative feedstock to LVA and LVA esters is being examined. For the homogeneous hydrogenation of LVA, molecular catalysts were evaluated. Consequently, tailored molecular catalyst systems enabled a selective hydrogenation. With that, the first milestone of the project was achieved. A scalable synthetic protocol for the preparation of selected catalyst has been developed and application testing is 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 cyclization of MeBDO to 2-MTHF. Based on these findings, the engineering team has prepared a basic design for a continuous demo-plant to hydrogenate LVA. 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. The catalyst system developed within the project is the only system capable of hydrogenation of LVA via GVL to MeBDO. The significant technical progress in hydrogenation catalyst partially meets the catalyst performance required for a ton-scale continuous hydrogenation plant. Optimization of the catalyst continued during RP3. The investigation resulted in suitable reaction parameters for the continuous stirred tank reactor (CSTR) application. Construction of a CSTR is in progress. In parallel > 25 kg of MeBDO meeting the requested technical specifications & purity has been produced for the product development trials & for regulatory studies. In parallel, evaluation of heterogeneously catalysed hydrogenation of LVA is on-going. For application & development of hydrogenation intermediates, technical analysis indicated 2-MTHF as a replacement for fossil-based solvent THF. Further improvements in manufacturing of P2-MTHF led to high quality polymers that demonstrated a potential use in conventional polyurethane adhesives. In parallel, MeBDO polyesters were synthesized, screened, scaled up & tested for adhesive use. Initial results indicate promising novel bio-based materials with superior performance & properties compared to standard fossil-based alternatives. Several experiments for deeper formulation studies and testing were performed in RP3. 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. With that, project milestone “Polymer development” is achieved. Reactive two component (2C) epoxy adhesives with the GVL-derivative have been developed. Risk assessment of hydrogenation intermediates is in progress. Extensive literature review has been carried out to gather data on the physical-chemical properties, human toxicity, eco-toxicity (hazard assessment) and environmental fate (biodegradation, bioaccumulation) of bio-based chemicals and their respective fossil-based benchmarks. The missing data gaps especially for the bio-based derivatives are identified and a stepwise strategy for data completion has been designed. With this the project milestone “Data gap and strategy for data completion” is achieved. In RP3, toxicity screening for developmental toxicity was performed using a non-animal alternative method. Initial results indicated that GVL and MeBDO are not teratogenic. Also no acute ecotoxicity effect was observed at the tested GVL concentration. Further testing is in progress. Life-cycle modelling for the three fossil-based intermediate reference products & solvents has been completed. Data acquisition is in progress for the bio-based processes. Intermediatory results indicate that the environmental impact of the bio-based value chain is highly sensitive towards different scenarios of co-product (biochar) utilisation.
LVA production at NGP2 in a technical environment is a key step towards the scheduled economic & carbon neutral production of a highly significant platform chemical. As an impactful outcome of the process design, a new tailored purification strategy was developed & implemented at scale. This progress will allow the production of LVA with the required purity for the subsequent hydrogenation. In parallel, a molecular catalyst was developed for the subsequent hydrogenation of LVA to the target products. 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. Knowledge has been obtained on the production of kg amounts of Triphos ligands, on the scale-up of ligands & hydrogenation products of LVA. 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 CASE (coatings, adhesives, sealants and elastomers) market. Finally, GVL derivatives also appear very promising for different reactive adhesive applications. These bio-based products, based on the LVA platform, are expected to have a better technical performance and improved eco-toxicity and pharmacological properties compared to the established fossil-based counterparts. Initial LCA results indicate favourable environmental performance of the GreenSolRes products. By testing the safety of renewable bio-based products, confidence in bio-based products will increase as uncertainty decreases.