Roberto Rinaldi

This webinar brings together two internationally recognized scholars, **Dr. Sudha Goel** and **Dr. Roberto Rinaldi** whose work contributes to advancing circularity across technological, industrial and societal systems. Although circular economy principles are widely promoted, their practical implementation requires interdisciplinary collaboration and evidence‑based strategies that address material flows, technological constraints and governance structures. Dr. Sudha Goel, Professor of Civil Engineering at the Indian Institute of Technology, Kharagpur, India specializes in water quality, waste management and sustainable infrastructure, with a strong focus on resource‑efficient systems in rapidly urbanizing contexts. Dr. Roberto Rinaldi, Associate Professor of Sustainable Chemistry at Imperial College, London, UK is known for his pioneering research on lignocellulosic biomass, catalytic transformations and the development of sustainable materials. Their talks will explore how transitions in product design, production processes and policy frameworks can support the shift toward more circular and resource‑efficient systems. The discussion will highlight the importance of interdisciplinary research, technological innovation and governance mechanisms in enabling more sustainable patterns of production and consumption. This session forms part of a broader webinar series dedicated to advancing knowledge and practice related to responsible production and consumption. This webinar is part of the ongoing SDG Talks series curated by the **SDG 12 Working Group**, under the overarching theme **“Sustainable Industries for SDG 12.”** The series highlights critical dimensions of sustainable practices across diverse sectors, showing innovative approaches to responsible production, consumption, and systemic transformation.

SI ₃₂₀ identifies RCF-stabilised lignins with minimal degradation chromophores. GPC–UV–Vis SI ₃₂₀ ( M ) profiles show oligomer downshifts from chromophore build-up during catalyst ageing, preceding monomer yield loss.

Reductive Catalytic Fractionation (RCF) of lignocellulosic materials produces lignin oil rich in monomer products and high‐quality cellulosic pulps. RCF lignin oil also contains lignin oligomers/polymers and hemicellulose‐derived carbohydrates. The variety of components makes lignin oil a complex matrix for analytical methods. As a result, the signals are often convoluted and overlapped, making detecting and quantifying key intermediates challenging. Therefore, to investigate the mechanisms underlining lignin stabilization and elucidate the structural features of carbohydrates occurring in the RCF lignin oil, fractionation methods reducing the RCF lignin oil complexity are required. This report examines the solvent fractionation of RCF lignin oil as a facile method for producing lignin oil fractions for advanced characterization. Solvent fractionation uses small volumes of environmentally benign solvents (methanol, acetone, and ethyl acetate) to produce multigram lignin fractions comprising products in different molecular weight ranges. This feature allows the determination of structural heterogeneity across the entire molecular weight distribution of the RCF lignin oil by high‐resolution HSQC NMR spectroscopy. This study provides detailed insight into the role of the hydrogenation catalyst (Raney Ni) in stabilizing lignin fragments and defining the structural features of hemicellulose‐derived carbohydrates in lignin oil obtained by the H‐transfer RCF process.

Reductive Catalytic Fractionation (RCF) of lignocellulosic materials produces lignin oil rich in monomer products and high-quality cellulosic pulps. RCF lignin oil also contains lignin oligomers/polymers and hemicellulose-derived carbohydrates. The variety of components makes lignin oil a complex matrix for analytical methods. As a result, the signals are often convoluted and overlapped, making detecting and quantifying key intermediates challenging. Therefore, to investigate the mechanisms underlining lignin stabilization and elucidate the structural features of carbohydrates occurring in the RCF lignin oil, fractionation methods reducing the RCF lignin oil complexity are required. This report examines the solvent fractionation of RCF lignin oil as a facile method for producing lignin oil fractions for advanced characterization. We demonstrate solvent fractionation using small volumes of environmentally benign solvents (methanol, acetone, and ethyl acetate) to produce multigram lignin fractions comprising products in different molecular weight ranges. This feature allowed for determining structural heterogeneity across the entire molecular weight distribution of the RCF lignin oil via high-resolution HSQC NMR spectroscopy. This study provides detailed insight into the role of the hydrogenation catalyst (Raney Ni) in stabilizing lignin fragments and defining the structural features of hemicellulose-derived carbohydrates in lignin oil obtained by the H transfer RCF process.

Reductive catalytic fractionation (RCF) is a promising approach to fractionate lignocellulose and convert lignin to a narrow product slate. To guide research towards commercialization, cost and sustainability must be considered. Here we report a techno-economic analysis (TEA), life cycle assessment (LCA), and air emission analysis of the RCF process, wherein biomass carbohydrates are converted to ethanol and the RCF oil is the lignin-derived product. The base-case process, using a feedstock supply of 2000 dry metric tons per day, methanol as a solvent, and H₂ gas as a hydrogen source, predicts a minimum selling price (MSP) of crude RCF oil of $1.13 per kg when ethanol is sold at $2.50 per gallon of gasoline-equivalent ($0.66 per liter of gasoline-equivalent). We estimate that the RCF process accounts for 57% of biorefinery installed capital costs, 77% of positive life cycle global warming potential (GWP) (excluding carbon uptake), and 43% of positive cumulative energy demand (CED). Of $563.7 MM total installed capital costs, the RCF area accounts for $323.5 MM, driven by high-pressure reactors. Solvent recycle and water removal via distillation incur a process heat demand equivalent to 73% of the biomass energy content, and accounts for 35% of total operating costs. In contrast, H₂ cost and catalyst recycle are relatively minor contributors to operating costs and environmental impacts. In the carbohydrate-rich pulps, polysaccharide retention is predicted not to substantially affect the RCF oil MSP. Analysis of cases using different solvents and hemicellulose as an in situ hydrogen donor reveals that reducing reactor pressure and the use of low vapor pressure solvents could reduce both capital costs and environmental impacts. Processes that reduce the energy demand for solvent separation also improve GWP, CED, and air emissions. Additionally, despite requiring natural gas imports, converting lignin as a biorefinery co-product could significantly reduce non-greenhouse gas air emissions compared to burning lignin. Overall, this study suggests that research should prioritize ways to lower RCF operating pressure to reduce capital expenses associated with high-pressure reactors, minimize solvent loading to reduce reactor size and energy required for solvent recovery, implement condensed-phase separations for solvent recovery, and utilize the entirety of RCF oil to maximize value-added product revenues.

With these guidelines, we aim to unite the lignin-first biorefining research field around best practices for performing or reporting feedstock analysis, reactor design, catalyst performance, and product yields.