Chemocatalytic lignin valorization strategies are critical for a sustainable bioeconomy, as lignin, especially technical lignin, is one of the most available and underutilized aromatic feedstocks. Here, we provide the first report of an intensified reactive distillation–reductive catalytic deconstruction (RD-RCD) process to concurrently deconstruct technical lignins from diverse sources and purify the aromatic products at ambient pressure. We demonstrate the utility of RD-RCD bio-oils in high-performance additive manufacturing via stereolithography 3D printing and highlight its economic advantages over a conventional reductive catalytic fractionation/RCD process. As an example, our RD-RCD reduces the cost of producing a biobased pressure-sensitive adhesive from softwood Kraft lignin by up to 60% in comparison to the high-pressure RCD approach. Last, a facile screening method was developed to predict deconstruction yields using easy-to-obtain thermal decomposition data. This work presents an integrated lignin valorization approach for upgrading existing lignin streams toward the realization of economically viable biorefineries.

Lignin availability has increased significantly due to the commercialization of several processes for recovery and further development of alternatives for integration into Kraft pulp mills. Also, progress in lignin characterization, understanding of its chemistry as well as processing methods have resulted in the identification of novel lignin-based products and potential derivatives, which can serve as building block chemicals. However, all these have not led to the successful commercialization of lignin-based chemicals and materials. This is because most analyses and characterizations focus only on the technical suitability and quantify only the composition, functional groups present, size and morphology. Optical properties, such as the colour, which influences the uptake by users for diverse applications, are neither taken into consideration nor analysed. This paper investigates the quantification of lignin optical properties and how they can be influenced by process operating conditions. Lignin extraction conditions were also successfully correlated to the powder colour. About 120 lignin samples were collected and the variability of their colours quantified with the CIE L*a*b* colour space. In addition, a robust and reproducible colour measurement method was developed. This work lays the foundation for identifying chromophore molecules in lignin, as a step towards correlating the colour to the functional groups and the purity.

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2,5-Furandicarboxylic acid (FDCA) is a platform chemical for polyethylene furanoate (PEF) manufacturing, a promising biobased and green alternative to polyethylene terephthalate (PET) with a market size of 1.8 million tonne/ annum. There are several routes to produce FDCA, all through 5hydroxymethylfurfural (HMF) conversion. The traditional thermochemical process is highly energy intensive with a low yield. The electrocatalytic pathway, on the other hand, is gaining increased interest for it makes the process control more efficient, achieves a higher yield, and more importantly can be driven by renewable electricity to lower the environmental impact compared to the thermochemical process. This study assesses the economic aspects and environmental impacts of the electrochemical production of FDCA. It is found that the net present value (NPV) of the integrated electrochemical conversion and product separation plant is highly profitable, $72 million for 100 tonne/day production of FDCA, under optimistic conditions. It also reveals that the HMF price has significant impact on process economics, and the current density has the largest scope of improvement. The life-cycle assessment (LCA) results indicate that processes related to HMF production contribute the most to the overall environmental impactscalling for low impact HMF production processes, with cost reductionshowever, the impacts of the electrochemical route are much lower in comparison with the thermochemical route.

Furfural is a versatile platform and multipurpose chemical that can be produced with no carbon efficiency loss from pentose sugars present in prehydrolysate streams. Existing processes for the production of furfural are typically energy-intensive with limitations to recover value-added molecules and byproducts such as lignin and acetic acid. In this work, we demonstrate a novel integrated biorefinery process for furfural production with significant sustainability improvements to current production pathways. Higher conversion efficiency for C5 sugars into furfural is achieved with a novel reactor for producing and recovering furfural in the vapor phase that has been validated at the laboratory scale. Low molecular weight and sulfur-free lignin is also recovered while minimizing energy consumption by employing membrane filtration. Synergy was observed when lignin recovery is performed prior to furfural production. On the basis of experimental results, the scalability of the process for valorizing 3200 metric tonne/day of prehydrolysate solutions that is typically combusted in kraft dissolving pulp mills was evaluated. For a furfural production capacity of 36 tonne/day, a process configuration that stands out among four proposed alternatives was identified and designed. Significant heat energy savings (99.5%) for driving the process was achieved through a heat exchanger network design for internal heat recovery, which resulted in an energy intensity of 0.47 GJ/tonne, corresponding to 1% of the energy intensity for conventional processes. The technoeconomic assessment confirmed that even the least performing process is profitable, robust, and capital-efficient as indicated by metrics such as the internal rate of return (IRR) ranging from 30% to 46%, resistance to market uncertainty (RTMU) between 0.9 and 4.3 $/$, as well as return on capital employed (ROCE) between 49% and 91%.

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