Enhancing Aromatics Production in Zeolite-Catalyzed Lignin Pyrolysis by Establishing Structure-Acidity-Performance Relationships
- 1Institute of Sustainable and Circular Chemistry, Department of Chemistry, Faculty of Science, Utrecht University, Universiteitsweg 99, Utrecht, Netherlands, 3584 CG
- 2BASF Corporation, 100 Park Ave, Florham Park, NJ, United States of America, 07932
- 3BASF SE, Carl-Bosch-Strasse 38, Ludwigshafen am Rhein, Germany, 67056
Abstract
Selective pyrolysis of lignin into aromatics remains a major challenge due to its high oxygen content and structural complexity. Solid acid catalysts, like zeolites, are well known as effective catalysts for pyrolysis processes. However, the role of acid site density and strength in controlling aromatic yields in lignin pyrolysis remains insufficiently understood. Here, three zeolite framework topologies, namely FAU, MFI, and BEA, with distinct acidity profiles were systematically evaluated for lignin pyrolysis to disentangle zeolite framework topology and acidity effects. Significant variations in bio-oil and non-oxygenated aromatics (benzene, toluene, xylene (BTXs), and napthalenes) yields demonstrated that framework topology-dependent acid site strength plays a more dominant role than acid site density (bulk/external) in enhancing aromatics yield. Thermogravimetric analysis revealed that primary lignin depolymerization is not responsible for the product distribution variations observed. Instead, secondary reactions of oxygenated lignin fragments with acid sites dictate the overall deoxygenation performance. H-ZSM-5 exhibited the highest aromatics yields (100–132 mg g-1lignin), followed by H-Beta (35–52 mg g-1 lignin) and H-Y (8–22 mg g-1 lignin) zeolites. These values correspond to 4 to 16 % of theoretical maximum BTXs ring utilization efficiency (RUE), a benchmark that we propose to evaluate catalyst efficiency in lignin pyrolysis, defined as the ratio of experimentally obtained BTXs to the theoretical maximum based on phenylpropanoid units (C9) in lignin. Regeneration studies revealed gradual catalyst deactivation due to the conversion of strong acid sites (SAS) to intermediate acid sites (IAS) resulting in lower BTXs RUE per cycle. Overall, this work highlights the role of zeolite framework topology-driven confinement effects in controlling the acid site strength and thereby, governing lignin pyrolysis performance.
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BibTeX
@misc{sajwan2026enhancing,
title = {{Enhancing Aromatics Production in Zeolite-Catalyzed Lignin Pyrolysis by Establishing Structure-Acidity-Performance Relationships}},
author = {Devanshu Sajwan and Lucas Dorazio and Nils Bottke and Andrei N. Parvulescu and Matteo Monai and Bert M. Weckhuysen},
howpublished = {ChemRxiv},
year = {2026},
month = sep,
doi = {10.26434/chemrxiv.15009058/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009058/v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Enhancing Aromatics Production in Zeolite-Catalyzed Lignin Pyrolysis by Establishing Structure-Acidity-Performance Relationships
AU - Devanshu Sajwan
AU - Lucas Dorazio
AU - Nils Bottke
AU - Andrei N. Parvulescu
AU - Matteo Monai
AU - Bert M. Weckhuysen
PY - 2026
DA - 2026/09/18
PB - ChemRxiv
DO - 10.26434/chemrxiv.15009058/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009058/v1
AB - Selective pyrolysis of lignin into aromatics remains a major challenge due to its high oxygen content and structural complexity. Solid acid catalysts, like zeolites, are well known as effective catalysts for pyrolysis processes. However, the role of acid site density and strength in controlling aromatic yields in lignin pyrolysis remains insufficiently understood. Here, three zeolite framework topologies, namely FAU, MFI, and BEA, with distinct acidity profiles were systematically evaluated for lignin pyrolysis to disentangle zeolite framework topology and acidity effects. Significant variations in bio-oil and non-oxygenated aromatics (benzene, toluene, xylene (BTXs), and napthalenes) yields demonstrated that framework topology-dependent acid site strength plays a more dominant role than acid site density (bulk/external) in enhancing aromatics yield. Thermogravimetric analysis revealed that primary lignin depolymerization is not responsible for the product distribution variations observed. Instead, secondary reactions of oxygenated lignin fragments with acid sites dictate the overall deoxygenation performance. H-ZSM-5 exhibited the highest aromatics yields (100–132 mg g-1lignin), followed by H-Beta (35–52 mg g-1 lignin) and H-Y (8–22 mg g-1 lignin) zeolites. These values correspond to 4 to 16 % of theoretical maximum BTXs ring utilization efficiency (RUE), a benchmark that we propose to evaluate catalyst efficiency in lignin pyrolysis, defined as the ratio of experimentally obtained BTXs to the theoretical maximum based on phenylpropanoid units (C9) in lignin. Regeneration studies revealed gradual catalyst deactivation due to the conversion of strong acid sites (SAS) to intermediate acid sites (IAS) resulting in lower BTXs RUE per cycle. Overall, this work highlights the role of zeolite framework topology-driven confinement effects in controlling the acid site strength and thereby, governing lignin pyrolysis performance.
ER -