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Understanding and manipulating free radicals in lignin for a controlled depolymerization to chemicals

English title Understanding and manipulating free radicals in lignin for a controlled depolymerization to chemicals
Applicant Vogel Frédéric
Number 136892
Funding scheme NRP 66 Resource Wood
Research institution Allgemeine Energieforschung Paul Scherrer Institut
Institution of higher education Paul Scherrer Institute - PSI
Main discipline Chemical Engineering
Start/End 01.04.2012 - 30.06.2017
Approved amount 637'522.00
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All Disciplines (2)

Discipline
Chemical Engineering
Physical Chemistry

Keywords (6)

EPR; Free radicals; Spectroscopy; Depolymerization; Characterization; Lignin

Lay Summary (German)

Lead
Freie Radikale im Lignin als Schlüssel zur Herstellung "grüner" Chemikalien Freie Radikale im Lignin stellen vermutlich den Schlüssel zu seiner chemischen Zerle-gung in wertvolle Chemikalien dar. Gelingt es, die Art und Anzahl dieser Radikale zu beeinflussen, könnte dies zu neuen Verfahren für die Herstellung von "grünen" Chemi-kalien führen.
Lay summary

Hintergrund
Biomasse hat das Potenzial, Erdöl in absehbarer Zeit als Ausgangssubstanz für die Herstellung chemischer Produkte zu ersetzen. Die Grundbausteine der Biomasse sind organische Kohlenstoffverbindungen, darunter auch sogenannte aromatische Kohlenwasserstoffe. Diese sind im Lignin – der "Kittsubstanz" der Pflanzen – in verschiedenen Varianten zu einem grossen Molekül (Makromolekül) vernetzt. Um die aromatischen Kohlenstoffverbindungen im Lignin als Chemikalien nutzen zu können, müssen sie in die einzelnen Moleküle gespalten werden. Ohne zu verstehen, wie Lignin aufgebaut ist und wie es unter chemischen "Belastungen" reagiert, erhält man neben vielen ähnlichen nur kleine Mengen der erwünschten Substan-zen.

Ziel
Das Makromolekül Lignin ist je nach Pflanze unterschiedlich aufgebaut. Auch die Art, wie das Lignin aus der Pflanze herausgelöst wird, verändert jeweils das Lignin in seiner Struktur. In diesem Projekt lösen die Forschenden Lignine aus Buche, Fichte, Pappel und Kiefer mit bekannten chemischen Methoden heraus und analysieren deren Zusammensetzung, Struktur und chemische Eigenschaften. Neben den Standardanalysen kommt insbesondere die sogenannte Elektronenspinresonanz-Spektroskopie zur Anwendung, um Art und Konzentrati-on der freien Radikale zu bestimmen. Durch Verändern des Lösungsmittels und anderer Parameter wie pH, Temperatur und der Zugabe von Katalysatoren, bestimmen die Forschenden, wie sich Art und Konzentration der freien Radikale verändern. Die neuen Erkenntnisse dienen schliesslich dazu, um aus dem Lignin durch thermochemische Spaltung (z. B. durch katalytische Flash-Pyrolyse) wirtschaftlich verwertbare Phenole herzustellen.

Bedeutung
Die Forschungsarbeiten können neue, grundlegende Erkenntnisse über die Reaktivität von Lignin liefern, die es in Zukunft ermöglichen könnten, Lignin zu zerlegen und auf dieser Basis fortan "grüne" Chemikalien wirtschaftlich zu produzieren.

Direct link to Lay Summary Last update: 29.01.2013

Lay Summary (French)

Lead
Les radicaux libres dans la lignine: la clé de la fabrication de substances chimiques "vertes" Les radicaux libres présents dans la lignine sont probablement la clé de sa décomposition chimique en de précieuses substances. Réussir à influencer la nature et le nombre de radicaux pourrait aboutir à de nouveaux procédés d’élaboration de produits chimiques "verts".
Lay summary

Contexte
Dans un futur proche, la biomasse a le potentiel de remplacer le pétrole comme matière de base pour la fabrication de produits chimiques. Les constituants élémentaires de la biomasse sont des composés carbonés organiques, notamment des hydrocarbures aromatiques. Dans la lignine, le "ciment" végétal, elles sont réticulées selon différentes variantes pour former une grosse molécule (macromolécule). Pour être utilisables sous forme de produits chimiques, les composés carbonés aromatiques de la lignine doivent être fragmentés en différentes molécules. Si l’on ne comprend pas la structure de la lignine et ses réactions sous les "charges" chimiques, on n’obtient que de faibles quantités des substances souhaitées, en plus de nombreuses substances similaires.

But
La structure macromoléculaire de la lignine varie d’une plante à l’autre. Le mode d’extraction de la lignine modifie également la lignine et sa structure. Dans ce projet, les chercheurs extraient la lignine du hêtre, de l’épicéa, du peuplier et du pin en recourant à des méthodes chimiques connues pour en analyser la composition, la structure et les propriétés chimiques. Pour déterminer les types des radicaux libres et leur concentration, ils procèdent aux analyses standard mais font aussi un usage intense de la spectrographie de résonance paramagnétique électronique. En modifiant le solvant et d’autres paramètres tels que le pH, la température ou par ajout de catalyseurs, les chercheurs déterminent les modifications des types de radicaux libres et leur concentration. Les conclusions tirées des travaux visent à produire des phénols économiquement exploitables par le fractionnement thermochimique (par ex. par pyrolyse flash catalytique).

Portée
Les travaux de recherche peuvent apporter de nouvelles connaissances fondamentales sur la réactivité de la lignine, qui pourraient permettre une décomposition de la lignine et, sur cette base, la production rentable de substances chimiques "vertes".

Direct link to Lay Summary Last update: 29.01.2013

Lay Summary (English)

Lead
Free radicals in lignin as the key to "green" chemicals Free radicals in the lignin probably present the key to its chemical breakdown into valuable chemicals. Should it be possible to influence the type and number of these highly chemically active molecules, this could lead to new procedures for making "green" chemicals.
Lay summary

Background
Biomass has the potential to replace fossil oil in the near future as a starting substance for the production of chemical products. The basic components of biomass are organic carbon compounds, including so-called aromatic hydrocarbons. In lignin—the "glue" that holds plants together—the latter are cross-linked in different ways to form a large molecule (macromole-cule). In order to be able to use the aromatic hydrocarbons in lignin as chemicals, they need to be split up into individual molecules. Without an understanding of the composition of lignin and of how it reacts to chemical "pressures", it is not possible to obtain more than a little of the desired substances, alongside many substances that are similar.

Aim
The macromolecule lignin has a different composition from plant to plant. The manner in which the lignin is retrieved from the plant also changes the structure of the lignin. In this project, researchers retrieve lignin from beech, spruce, poplar and pine using recognised chemical methods and analyse its composition, structure and chemical properties. Alongside the standard analyses, the researchers apply, in particular, electron paramagnetic resonance spectroscopy in order to determine the nature and concentration of the free radicals. By changing the solvent and other parameters such as pH, temperature and the addition of catalysts, the researchers find out how the nature and concentration of the free radicals change. The new insights will be used to produce commercially exploitable phenols from lignin via thermochemical splitting (e.g. through catalytic flash pyrolisis).

Significance
The research work can generate new, fundamental knowledge about the reactivity of lignin. In the future, this may enable researchers to break down lignin and subsequently produce "green" chemicals economically.

Direct link to Lay Summary Last update: 29.01.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Catalytic Fast Pyrolysis of Lignin over High-Surface-Area Mesoporous Aluminosilicates: Effect of Porosity and Acidity
Custodis Victoria, Karakoulia S.A., Triantafyllidis K.S., van Bokhoven J.A. (2016), Catalytic Fast Pyrolysis of Lignin over High-Surface-Area Mesoporous Aluminosilicates: Effect of Porosity and Acidity, in ChemSusChem, 9(10), 1134-1145.
In Situ High Temperature Electron Paramagnetic Resonance Spectroscopy Study on the Influence of Zeolites on the Radical Formation during Lignin Pyrolysis
Bährle Christian, Custodis Victoria, Jeschke Gunnar, van Bokhoven Jeroen, Vogel Frédéric (2016), In Situ High Temperature Electron Paramagnetic Resonance Spectroscopy Study on the Influence of Zeolites on the Radical Formation during Lignin Pyrolysis, in ChemSusChem, 9, 2397-2403.
Chemicals from Lignin by Catalytic Fast Pyrolysis, from Product Control to Reaction Mechanism
Ma Zhiqiang, Custodis Victoria, Hemberger Patrik, Bährle Christian, Vogel Frédéric, Jeschke Gunnar, van Bokhoven Jeroen (2015), Chemicals from Lignin by Catalytic Fast Pyrolysis, from Product Control to Reaction Mechanism, in Chimia, 69(10), 597-602.
High-Field Electron Paramagnetic Resonance and Density Functional Theory Study of Stable Organic Radicals in Lignin: Influence of the Extraction Process, Botanical Origin, and Protonation Reactions on
Bährle Christian, Nick Thomas, Bennati Marina, Jeschke Gunner, Vogel Frédéric (2015), High-Field Electron Paramagnetic Resonance and Density Functional Theory Study of Stable Organic Radicals in Lignin: Influence of the Extraction Process, Botanical Origin, and Protonation Reactions on, in J. Phys. Chem. A, 119(24), 6475-6482.
Phenols and Aromatics from Fast Pyrolysis of variously prepared Lignins from Hard- and Softwoods
Custodis Victoria, Bährle Christian, Vogel Frédéric, van Bokhoven Jeroen (2015), Phenols and Aromatics from Fast Pyrolysis of variously prepared Lignins from Hard- and Softwoods, in Journal of Analytical and Applied Pyrolysis, 115, 214-223.
In Situ Observation of Radicals and Molecular Products during Lignin Pyrolysis
Bährle C., Custodis V., Jeschke G., van Bokhoven J.A., Vogel F. (2014), In Situ Observation of Radicals and Molecular Products during Lignin Pyrolysis, in ChemSusChem, 7, 2022-2029.
Mechanism of Fast Pyrolysis of Lignin: Studying Model Compounds
Custodis V.B.F., Hemberger P., Ma Z., van Bokhoven J. A. (2014), Mechanism of Fast Pyrolysis of Lignin: Studying Model Compounds, in Journal of Physical Chemistry B, 118(29), 8524-8531.
Selective deoxygenation of lignin during catalytic fast pyrolysis
Ma Zhiqiang, Custodis Victoria, van Bokhoven Jeroen (2014), Selective deoxygenation of lignin during catalytic fast pyrolysis, in Catalysis Science & Technology, 4, 766-772.

Collaboration

Group / person Country
Types of collaboration
MPI Biophysikalische Chemie, Göttingen Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Prof. Dr. Jeremy Luterbacher Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Research Infrastructure
Prof. Dr. F. Maréchal (EPFL) Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
Prof. Ph. Rudolf von Rohr (ETHZ) Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
16th International Congress on Catalysis Poster The Mechanism of Catalytic Fast Pyrolysis of Lignin 03.07.2016 Beijing, China Custodis Victoria; van Bokhoven Jeroen Anton;
21st International Symposium on Analytical and Applied Pyrolysis Talk given at a conference The Mechanism of Catalytic Fast Pyrolysis 09.05.2016 Nancy, France van Bokhoven Jeroen Anton; Custodis Victoria;
SCS Fall Meeting of Swiss Chemical Society Poster Fast Pyrolysis of Lignin: Relating the Structure with Product Selectivity 04.09.2015 Lausanne, Switzerland Custodis Victoria; Ma Zhiqiang; van Bokhoven Jeroen Anton;
249th American Chemical Society National Meeting Talk given at a conference The Mechanism of Lignin Pyrolysis – from Model Compound to actual Lignin 22.03.2015 Denver, CO, United States of America Ma Zhiqiang; van Bokhoven Jeroen Anton; Custodis Victoria;
Photon Tools for Physical Chemistry Talk given at a conference Decomposition Mechanism of Lignin Model Compounds using the IPEPICO setup 28.09.2014 Beatenberg, Switzerland van Bokhoven Jeroen Anton; Custodis Victoria;
SCS Fall Meeting of Swiss Chemical Society Poster Investigating the Mechanism of Lignin Pyrolysis – a model compound study 11.09.2014 Zürich, Switzerland van Bokhoven Jeroen Anton; Custodis Victoria;
8th International Conference on Environmental Catalysis Talk given at a conference Catalytic Fast Pyrolysis of Lignin-Tuning Selectivity by Transition Metal Deposition 25.08.2014 Ashville, NC, United States of America van Bokhoven Jeroen Anton; Custodis Victoria;
Lignin 2014 - biosynthesis and utilization Talk given at a conference Observation of radicals formed during lignin pyrolysis using in situ high temperature EPR 24.08.2014 Umeå, Sweden Custodis Victoria; Jeschke Gunnar; Vogel Frédéric; van Bokhoven Jeroen Anton; Bährle Christian;
Summer School Catalysis of Biomass Talk given at a conference Decomposition Mechanism of Lignin Fast Pyrolysis 08.06.2014 Liblice, Czech Republic Custodis Victoria; van Bokhoven Jeroen Anton;
20th International Symposium on Analytical & Applied Pyrolysis Pyro 2014 Talk given at a conference The influence of zeolites on the radical formation during lignin pyrolysis studied by electron paramagnetic resonance spectroscopy 19.05.2014 Birmingham, Great Britain and Northern Ireland Custodis Victoria; Jeschke Gunnar; van Bokhoven Jeroen Anton; Bährle Christian; Vogel Frédéric;
Biorefinery & Nano-cellulose, INNOBITE 1st Workshop Talk given at a conference Lignin: structure, reactivity and molecular products 16.09.2013 EMPA, Dübendorf, Switzerland Vogel Frédéric; Bährle Christian;
21st European Biomass Conference and Exhibition Talk given at a conference In Situ Observation of Radicals formed during Lignin Pyrolysis 03.06.2013 Kopenhagen, Denmark Vogel Frédéric; Bährle Christian;


Abstract

This research project aims at contributing towards viable processes for the production of chemicals from lignin by focusing on the chemical reactivity of lignin as a feedstock for functionalized aromatic moieties, e.g. phenolics and polyphenolics. We propose to perform a detailed study on a range of model lignins extracted in exactly the same way, and including also technical lignins. Several state-of-the-art spectroscopy techniques such as IR, UV-Vis, NMR, XPS, EPR will be applied. Emphasis will be given on the free radical character of lignin. Learnings from the structural characterization will be tested and validated using catalytic flash pyrolysis. We seek funding for two PhD students located at ETHZ and PSI complementing each other. The results of this project will be of great value to all more applied projects aiming at depolymerizing the lignin with specific processes, e.g. selective oxidation or hydrogenation.
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