Center for Molecular Modeling - B. F. Sels

Confined hot-pressurized water in Brønsted-acidic beta zeolite speeds up the O-demethylation of guaiacol

massimo — Thu, 24 Nov 2022 13:15:33 +0000

M. Bocus, E. Van den Broeck, X. Wu, M. Bal, J. Bomon, L. Vanduyfhuys, B. F. Sels, B. U. W. Maes, V. Van Speybroeck

Nature Catalysis

8, 33-45

2025

Abstract

Biorefinery technologies that convert lignin into platform chemicals are essential to reduce our future dependence on fossil resources. In these technologies, a key process is the acid-catalysed O-demethylation of guaiacol derivatives in hot-pressurized water using Brønsted mineral acids or microporous zeolites. The fundamental understanding of how hydronium ions behave in a confined environment versus bulk is still limited. Here we investigate the O-demethylation of guaiacol in hot-pressurized water with HCl or H-BEA zeolite catalysts to elucidate the impact of zeolite microporosity on reaction mechanisms and rates. Operando molecular simulations combined with experimental kinetic studies reveal that, regardless of the catalyst type, O-demethylation follows a concerted O-activated S_N2 mechanism. The reaction rate is higher in the zeolite due to more active, under-coordinated hydronium ions. Additionally, the molecular organization of solvent and reactants around the confined active site plays a crucial role in modulating the association of the reacting species and the reaction kinetics.

DOI

https://doi.org/10.1038/s41929-024-01282-6

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Bocus_et_al-2025-Nature_Catalysis.pdf

Coordination and activation of nitrous oxide by iron zeolites

cnudde — Sat, 24 Apr 2021 15:43:49 +0000

M.L. Bols, B.E.R. Snyder, H.M. Rhoda, P. Cnudde, G. Fayad, R.A. Schoonheydt, V. Van Speybroeck, E.I. Solomon, B. F. Sels

Nature Catalysis

4, 332-340

2021

Abstract

Iron-containing zeolites are heterogeneous catalysts that exhibit remarkable activity in the selective oxidation of inert hydrocarbons and catalytic decomposition of nitrous oxide (N2O). The reduction of N2O is critical to both these functions, but experimental data tracking the iron active sites during N2O binding and activation are limited. Here, the N2O-ligated Fe(ii) active site in iron-exchanged zeolite beta is isolated and characterized by variable-temperature Mössbauer, diffuse reflectance UV-vis-NIR and Fourier transform infrared spectroscopy. N2O binds through the terminal nitrogen atom with substantial backbonding from the Fe(ii) centre at low temperature. At higher temperatures, the Fe–N2O interaction is weakened, facilitating isomerization to the O-bound form, which is competent in O-atom transfer. Density functional theory calculations show the geometric and electronic structure requirements for N2O binding and activation. A geometric distortion imposed by the zeolite lattice plays an important role in activating N2O. This highlights a mechanism for structural control over function in Fe-zeolite catalysts.

DOI

http://dx.doi.org/10.1038/s41929-021-00602-4

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Manuscript_final.pdf

Brønsted Acid Catalyzed Tandem Defunctionalization of Biorenewable Ferulic acid and Derivates into Bio-catechol

samuel — Fri, 10 Jan 2020 13:57:03 +0000

J. Bomon, E. Van den Broeck, M. Bal, Y. H. Liao, S. Sergeyev, V. Van Speybroeck, B. F. Sels, B. U. W. Maes

Angewandte Chemie int. Ed.

59 (8), 3063-3068

2020

Abstract

An efficient conversion of biorenewable ferulic acid into bio‐catechol has been developed. The transformation comprises two consecutive defunctionalizations of the substrate, that is, C−O (demethylation) and C−C (de‐2‐carboxyvinylation) bond cleavage, occurring in one step. The process only requires heating of ferulic acid with HCl (or H2SO4) as catalyst in pressurized hot water (250 °C, 50 bar N2). The versatility is shown on a variety of other (biorenewable) substrates yielding up to 84 % di‐ (catechol, resorcinol, hydroquinone) and trihydroxybenzenes (pyrogallol, hydroxyquinol), in most cases just requiring simple extraction as work‐up.

DOI

https://doi.org/10.1002/anie.201913023

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Bomon_et_al-2019-Angewandte_Chemie.pdf

Towards a realistic modeling of complex zeolite-catalyzed reactions: the case of guaiacol demethylation

massimo — Thu, 30 Jun 2022 07:53:39 +0000

M. Bocus, E. Van den Broeck, M. Bal, X. Wu, J. Bomon, L. Vanduyfhuys, B. U. W. Maes, B. F. Sels, V. Van Speybroeck

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Talk

Conference / event / venue

ICTAC 2022

Lyon, France

Monday, 13 June, 2022 to Friday, 17 June, 2022

Abstract (private)

BOCUS_Massimo_ictac2022.pdf

Mechanistic Insights on the Water-Zeolite Synergy in the Conversion of Biomass-Derived Guaiacol

massimo — Tue, 21 Sep 2021 11:43:37 +0000

M. Bocus, E. Van den Broeck, M. Bal, X. Wu, L. Vanduyfhuys, B. U. W. Maes, B. F. Sels, V. Van Speybroeck

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Poster

Conference / event / venue

Water in Zeolites Workshop

Liblice Castle, Czech Republic

Sunday, 19 September, 2021 to Wednesday, 22 September, 2021

Theoretical insights into mechanism and reactivity of zeolite-catalyzed alkylphenols dealkylation

massimo — Wed, 04 Mar 2020 09:22:46 +0000

M. Bocus, Y. Liao, B. F. Sels, V. Van Speybroeck

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NCCC XXI

Noordwijkerhout,The Netherlands

Monday, 2 March, 2020 to Wednesday, 4 March, 2020

Abstract (private)

n3c_abstract.pdf

Ab initio modeling of the zeolite-catalyzed conversion of alkylphenols into phenol and olefins

massimo — Mon, 20 Jan 2020 15:30:51 +0000

M. Bocus, J. Hajek, Y. Liao, B. F. Sels, V. Van Speybroeck

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Poster

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MolSim 2020

Amsterdam, The Nederlands

Monday, 6 January, 2020 to Friday, 17 January, 2020

Ab initio modeling of the zeolite-catalyzed conversion of alkylphenols into phenol and olefins

massimo — Mon, 20 Jan 2020 15:28:48 +0000

M. Bocus, J. Hajek, Y. Liao, B. F. Sels, V. Van Speybroeck

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Poster

Conference / event / venue

EuropaCat 2019

Aachen, Germany

Sunday, 18 August, 2019 to Friday, 23 August, 2019

First-principles mechanistic study of alkylphenols dealkylation catalyzed by acidic zeolites

massimo — Mon, 20 Jan 2020 15:23:46 +0000

M. Bocus, J. Hajek, Y. Liao, B. F. Sels, V. Van Speybroeck

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Poster

Conference / event / venue

NCCC XX

Noordwijkerhout,The Netherlands

Monday, 4 March, 2019 to Wednesday, 6 March, 2019

Transformation of aromatic biorefinery products into building blocks for fine chemicals

samuel — Fri, 10 Jan 2020 15:35:16 +0000

J. Bomon, E. Blondiaux, E. Van den Broeck, P. Mampuys, V. Van Speybroeck, B. F. Sels, B. U. W. Maes

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Talk

Conference / event / venue

23rd Merck Organic Chemistry Symposium

Belgium (Blankenberge)

Thursday, 5 December, 2019 to Friday, 6 December, 2019

Abstract (private)

MOCS_2019_Jeroen Bomon.pdf