| 1. |
- Abu-Omar, Mahdi M., et al.
(författare)
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Guidelines for performing lignin-first biorefining
- 2021
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 14:1, s. 262-292
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Forskningsöversikt (refereegranskat)abstract
- The valorisation of the plant biopolymer lignin is now recognised as essential to enabling the economic viability of the lignocellulosic biorefining industry. In this context, the lignin-first biorefining approach, in which lignin valorisation is considered in the design phase, has demonstrated the fullest utilisation of lignocellulose. We define lignin-first methods as active stabilisation approaches that solubilise lignin from native lignocellulosic biomass while avoiding condensation reactions that lead to more recalcitrant lignin polymers. This active stabilisation can be accomplished by solvolysis and catalytic conversion of reactive intermediates to stable products or by protection-group chemistry of lignin oligomers or reactive monomers. Across the growing body of literature in this field, there are disparate approaches to report and analyse the results from lignin-first approaches, thus making quantitative comparisons between studies challenging. To that end, we present herein a set of guidelines for analysing critical data from lignin-first approaches, including feedstock analysis and process parameters, with the ambition of uniting the lignin-first research community around a common set of reportable metrics. These guidelines comprise standards and best practices or minimum requirements for feedstock analysis, stressing reporting of the fractionation efficiency, product yields, solvent mass balances, catalyst efficiency, and the requirements for additional reagents such as reducing, oxidising, or capping agents. Our goal is to establish best practices for the research community at large primarily to enable direct comparisons between studies from different laboratories. The use of these guidelines will be helpful for the newcomers to this field and pivotal for further progress in this exciting research area.
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| 2. |
- Bartling, Andrew W., et al.
(författare)
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Techno-economic analysis and life cycle assessment of a biorefinery utilizing reductive catalytic fractionation
- 2021
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 14:8, s. 4147-4168
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Tidskriftsartikel (refereegranskat)abstract
- 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 H-2 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, H-2 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.
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| 3. |
- Argyropoulos, Dimitris D. S., et al.
(författare)
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Kraft Lignin: A Valuable, Sustainable Resource, Opportunities and Challenges
- 2023
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Ingår i: ChemSusChem. - : John Wiley and Sons Inc. - 1864-5631 .- 1864-564X. ; 16:23
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Forskningsöversikt (refereegranskat)abstract
- Kraft lignin, a by-product from the production of pulp, is currently incinerated in the recovery boiler during the chemical recovery cycle, generating valuable bioenergy and recycling inorganic chemicals to the pulping process operation. Removing lignin from the black liquor or its gasification lowers the recovery boiler load enabling increased pulp production. During the past ten years, lignin separation technologies have emerged and the interest of the research community to valorize this underutilized resource has been invigorated. The aim of this Review is to give (1) a dedicated overview of the kraft process with a focus on the lignin, (2) an overview of applications that are being developed, and (3) a techno-economic and life cycle asseeements of value chains from black liquor to different products. Overall, it is anticipated that this effort will inspire further work for developing and using kraft lignin as a commodity raw material for new applications undeniably promoting pivotal global sustainability concerns.
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| 4. |
- Casey, Charles P., et al.
(författare)
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Quantitative Determination of the Regioselectivity of Nucleophilic Addition to η3-Propargyl Rhenium Complexes and Direct Observation of an Equilibrium between η3-Propargyl Rhenium Complexes and Rhenacyclobutenes.
- 2009
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Ingår i: Organometallics. - : American Chemical Society (ACS). - 0276-7333 .- 1520-6041. ; 28:1, s. 123-131
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Tidskriftsartikel (refereegranskat)abstract
- PMe3 adds selectively to the central C of the η3-propargyl complex [C5Me5(CO)2Re(η3-CH2C≡CCMe3)][BF4] (1-t-Bu) to form the metallacyclobutene [C5Me5(CO)2Re(CH2C(PMe3):CCMe3)][BF4] (7). The rate of rearrangement of the metallacyclobutene 7 to η2-alkyne complex [C5Me5(CO)2Re(η2-Me3PCH2C≡CCMe3)][BF4] (8) is independent of phosphine concn., consistent with a dissociative mechanism proceeding via η3-propargyl complex 1-t-Bu. The rate of this rearrangement is 480 times slower than the rate of exchange of PMe3 with the labeled metallacyclobutene 7-d9. This rate ratio provides an indirect measurement of the regioselectivity for addn. of PMe3 to the central C of η3-propargyl complex 1-t-Bu to give 7 compared to addn. to a terminal C to give 8. The addn. of PPh3 to 1-t-Bu gives the metallacyclobutene [C5Me5(CO)2Re(CH2C(PPh3):CCMe3)][BF4] (11). Low-temp. 1H NMR spectra provide evidence for an equil. between metallacyclobutene 11 and η3-propargyl complex 1-t-Bu (Keq ≈ 44 M-1 at -46° and ΔG°(0°) = -1.2 ± 0.2 kcal mol-1). The crystal and mol. structures of [C5Me5(CO)2Re[η2-(Ar2PCH2CH2PPh2)CH2C≡CCMe3]][BF4]·2CH2Cl2 (Ar = 3,5-(CF3)2C6H3) and [C5Me5(CO)2Re(η2-Me3PCH2C≡CCMe3)]Cl·H2O were detd. by x-ray crystallog. [on SciFinder(R)]
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| 5. |
- Lebedeva, Daria, 1994-, et al.
(författare)
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Synthesis of Cyclobutane-Based Sustainable Aviation Fuel from Prehydrolysis Liquors
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Maximizing products of high value and minimizing incineration of side-streams is key to realize future biorefineries. In current textile production from forestry, hemicellulose is removed by prehydrolysis before delignification. The resulting prehydrolysis liquor is incinerated in the recovery boiler at low efficiency. This additional burden on the limiting recovery boiler reduces the pulp production. In this study, we demonstrate that prehydrolysis liquor can be upgraded, in 5 steps, to yield aviation fuels. Prehydrolysis liquors were dehydrated to furfural by zeolite catalysis. Furfural was selecitvely reduced to furfuryl alcohol by homogeneous catalysis. Rhenium-catalyzed Achmatowicz rearrangement gave a C5 intermediate susceptable to self [2+2] cycloaddition to give the C10 oxygenated precursor. By using a combination of Ru/C and zeolites, full hydrodeoxygenation was achieved. The resulting hydrocarbons, containing a strained four-membered ring, are preferred aviation fuel components. This is an important step to show that aviation fuels can be produced sustainably from existing industrial side-streams.
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| 6. |
- Lebedeva, Daria, 1994-
(författare)
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Valorization of low-value lignocellulosic side-streams
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The development of novel pathways for valorizing low-value streams from pulp, forest, and agricultural industries is crucial for realizing a circular bioeconomy and addressing the needs of both platform chemicals and fuels. Utilizing hemicellulose and lignin as biomass-derived feedstocks facilitates the production of sustainable liquid hydrocarbons, with catalytic hydrodeoxygenation being a key process. In the utilization of hemicellulose for the synthesis of liquid hydrocarbons, the approach involves recovering hemicellulosic sugars from wood and transforming them into furfural, which undergoes catalytic hydrodeoxygenation using a noble metal/zeolite tandem catalyst. This results in the production of pentane as the primary product. The process also generates C7–C10 hydrocarbons through bimolecular condensation of oxygenated intermediates alongside the formation of aromatic structures. Another approach involves a three-step transformation of furfural, including furanic ring rearrangement and [2+2] cycloaddition, which produces a C10 oxygenated precursor with a 4-membered ring. Catalytic hydrodeoxygenation of this precursor results in the formation of cyclobutane-containing hydrocarbons for sustainable aviation fuel applications.In the utilization of lignin for the synthesis of liquid hydrocarbons, the approach involves lignin isolation from biomass and its direct catalytic hydrodeoxygenation into valuable platform chemicals and fuels. Guaiacol serves as a lignin model compound, facilitating optimization of the hydrotreatment process and giving insights into the distribution of the products. The hydrodeoxygenation of two different lignins, isolated from biomass by organosolv and soda pulping, yields bio-oils rich in hydrocarbons and suitable for transportation fuel applications.
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| 7. |
- Subbotina, Elena, et al.
(författare)
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Oxidative cleavage of C-C bonds in lignin
- 2021
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Ingår i: Nature Chemistry. - : Springer Science and Business Media LLC. - 1755-4330 .- 1755-4349. ; 13, s. 1118-1125
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Tidskriftsartikel (refereegranskat)abstract
- Lignin is an aromatic polymer that constitutes up to 30 wt% of woody biomass and is considered the largest source of renewable aromatics. Valorization of the lignin stream is pivotal for making biorefining sustainable. Monomeric units in lignin are bound via C–O and C–C bonds. The majority of existing methods for the production of valuable compounds from lignin are based on the depolymerization of lignin via cleavage of relatively labile C–O bonds within lignin structure, which leads to yields of only 36–40 wt%. The remaining fraction (60 wt%) is a complex mixture of high-molecular-weight lignin, generally left unvalorized. Here we present a method to produce additional valuable monomers from the high-molecular-weight lignin fraction through oxidative C–C bond cleavage. This oxidation reaction proceeds with a high selectivity to give 2,6-dimethoxybenzoquinone (DMBQ) from high-molecular-weight lignin in 18 wt% yield, thus increasing the yield of monomers by 32%. This is an important step to make biorefining competitive with petroleum-based refineries.
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| 8. |
- Watile, Rahul A., et al.
(författare)
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Intramolecular substitutions of secondary and tertiary alcohols with chirality transfer by an iron(III) catalyst
- 2019
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Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Optically pure alcohols are abundant in nature and attractive as feedstock for organic synthesis but challenging for further transformation using atom efficient and sustainable methodologies, particularly when there is a desire to conserve the chirality. Usually, substitution of the OH group of stereogenic alcohols with conservation of chirality requires derivatization as part of a complex, stoichiometric procedure. We herein demonstrate that a simple, inexpensive, and environmentally benign iron(III) catalyst promotes the direct intramolecular substitution of enantiomerically enriched secondary and tertiary alcohols with O-, N-, and S-centered nucleophiles to generate valuable 5-membered, 6-membered and aryl-fused 6-membered heterocyclic compounds with chirality transfer and water as the only byproduct. The power of the methodology is demonstrated in the total synthesis of (+)-lentiginosine from D-glucose where iron-catalysis is used in a key step. Adoption of this methodology will contribute towards the transition to sustainable and bio-based processes in the pharmaceutical and agrochemical industries. © 2019, The Author(s).
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| 9. |
- Adler, Anneli, et al.
(författare)
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Lignin-first biorefining of Nordic poplar to produce cellulose fibers could displace cotton production on agricultural lands
- 2022
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Ingår i: Joule. - : Elsevier BV. - 2542-4351. ; 6:8, s. 1845-1858
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Tidskriftsartikel (refereegranskat)abstract
- Here, we show that lignin-first biorefining of poplar can enable the production of dissolving cellulose pulp that can produce regenerated cellulose, which could substitute cotton. These results in turn indicate that agricultural land dedicated to cotton could be reclaimed for food production by extending poplar plantations to produce textile fibers. Based on climate-adapted poplar clones capable of growth on marginal lands in the Nordic region, we estimate an environmentally sustainable annual biomass production of ∼11 tonnes/ha. At scale, lignin-first biorefining of this poplar could annually generate 2.4 tonnes/ha of dissolving pulp for textiles and 1.1 m3 biofuels. Life cycle assessment indicates that, relative to cotton production, this approach could substantially reduce water consumption and identifies certain areas for further improvement. Overall, this work highlights a new value chain to reduce the environmental footprint of textiles, chemicals, and biofuels while enabling land reclamation and water savings from cotton back to food production.
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| 10. |
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