279 results on '"Bruijnincx, Pieter C. A."'
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2. Author Correction: Origin of active sites on silica–magnesia catalysts and control of reactive environment in the one-step ethanol-to-butadiene process
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Chung, Sang-Ho, Li, Teng, Shoinkhorova, Tuiana, Komaty, Sarah, Ramirez, Adrian, Mukhambetov, Ildar, Abou-Hamad, Edy, Shterk, Genrikh, Telalovic, Selvedin, Dikhtiarenko, Alla, Sirks, Bart, Lavrik, Polina, Tang, Xinqi, Weckhuysen, Bert M., Bruijnincx, Pieter C. A., Gascon, Jorge, and Ruiz-Martínez, Javier
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- 2023
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3. Molecular structure and composition elucidation of an industrial humin and its fractions.
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Constant, Sandra, Lancefield, Christopher S., Vogelzang, Willem, Pazhavelikkakath Purushothaman, Rajeesh Kumar, Frissen, Augustinus E., Houben, Klaartje, de Peinder, Peter, Baldus, Marc, Weckhuysen, Bert M., van Es, Daan S., and Bruijnincx, Pieter C. A.
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MOLECULAR structure ,GEL permeation chromatography ,CARBOXYLIC acids ,ELEMENTAL analysis ,ALIPHATIC alcohols ,NUCLEAR magnetic resonance spectroscopy ,MOLECULAR weights - Abstract
Humins, (side-)products of the acid-catalysed dehydration of carbohydrates, will be produced in substantial quantities with the development of industrial biorefining processes. Most structural knowledge about such humins is based on synthetic model humins prepared at lab-scale from typical carbohydrate(-derived) compounds. Here, we report the first extensive characterisation study of an industrial humin. The soluble humin was generated from pilot plant-scale methanolic cyclodehydration of D-fructose to 5-methoxymethyl-2-furfural (MMF), as part of the Avantium YXY® process to produce FDCA. Purification of the industrial humin followed by fractionation allowed isolation of a water-insoluble, high molecular weight fraction (WIPIH) and a water-soluble, low-to-middle molecular weight soluble fraction (WES). Characterisation by elemental analysis, thermogravimetry, IR and NMR spectroscopy and size exclusion chromatography provided a detailed picture of the humin structure in both fractions. Aided by a comprehensive NMR spectral library of furanic model compounds, we identified the main furanic building blocks and inter-unit linkages and propose a structure for this industrial humin sample. The WIPIH and WES fractions were found to be composed of furanic rings interconnected by short aliphatic chains containing a wide range of functionalities including alcohols, ethers, carboxylic acids, esters, aldehydes and ketones. The low level of crosslinking and high functional group content of the industrial humin differ from the more extensively studied, (highly over-)condensed synthetic model humins, towards which they can be considered intermediates. The structural and compositional insights into the nature of an actual industrial humin open up a broad spectrum of valorisation opportunities. [ABSTRACT FROM AUTHOR]
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- 2024
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4. Vanillic acid and methoxyhydroquinone production from guaiacyl units and related aromatic compounds using Aspergillus niger cell factories
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Lubbers, Ronnie J. M., Dilokpimol, Adiphol, Nousiainen, Paula A., Cioc, Răzvan C., Visser, Jaap, Bruijnincx, Pieter C. A., and de Vries, Ronald P.
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- 2021
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5. Predicting Molecular Weight Characteristics of Reductively Depolymerized Lignins by ATR-FTIR and Chemometrics.
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Riddell, Luke A., de Peinder, Peter, Polizzi, Viviana, Vanbroekhoven, Karolien, Meirer, Florian, and Bruijnincx, Pieter C. A.
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- 2024
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6. Rapid Lignin Thermal Property Prediction through Attenuated Total Reflectance‐Infrared Spectroscopy and Chemometrics.
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Riddell, Luke A., Lindner, Jean‐Pierre B., de Peinder, Peter, Meirer, Florian, and Bruijnincx, Pieter C. A.
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LIGNIN structure ,LIGNANS ,GLASS transition temperature ,LIGNINS ,STANDARD deviations ,THERMAL properties ,CHEMOMETRICS - Abstract
To expedite the valorisation of lignin as a sustainable component in materials applications, rapid and generally available analytical methods are essential to overcome the bottleneck of lignin characterisation. Where features of a lignin's chemical structure have previously been found to be predicted by Partial Least Squares (PLS) regression models built on Infrared (IR) data, we now show for the first time that this approach can be extended to prediction of the glass transition temperature (Tg), a key physicochemical property. This methodology is shown to be convenient and more robust for prediction of Tg than prediction through empirically derived relationships (e. g., Flory‐Fox). The chemometric analysis provided root mean squared errors of prediction (RMSEP) as low as 10.0 °C for a botanically, and a process‐diverse set of lignins, and 6.2 °C for kraft‐only samples. The PLS models could separately predict both the Tg as well as the degree of allylation (%allyl) for allylated lignin fractions, which were all derived from a single lignin source. The models performed exceptionally well, delivering RMSEP of 6.1 °C, and 5.4 %, respectively, despite the conflicting influences of increasing molecular weight and %allyl on Tg. Finally, the method provided accurate determinations of %allyl with RMSEP of 5.2 %. [ABSTRACT FROM AUTHOR]
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- 2024
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7. Semicontinuous Aqueous Acetone Organosolv Fractionation of Lignocellulosic Biomass: Improved Biorefinery Processing and Output.
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Smit, Arjan T., Hoek, Michiel, Bonouvrie, Petra A., van Zomeren, André, Riddell, Luke A., and Bruijnincx, Pieter C. A.
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- 2024
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8. Efficient synthesis of fully renewable, furfural-derived building blocks via formal Diels–Alder cycloaddition of atypical addends.
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Cioc, Răzvan C., Harsevoort, Eva, Lutz, Martin, and Bruijnincx, Pieter C. A.
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FURFURAL ,RING formation (Chemistry) ,ALLYL alcohol ,FURANS ,ACETAL resins ,STEREOSELECTIVE reactions - Abstract
Diels–Alder (DA) cycloaddition of furanics is emerging as a key transformation in circular chemistry, providing access to highly versatile, biobased platform molecules. Further development of this technology into viable industrial applications faces major challenges, a notorious one being the lack of reactivity of the most readily available furans, i.e. the furfural derivatives. Herein we describe the remarkably-facile intramolecular DA reaction of allyl acetals of different furfurals to efficiently afford formal DA adducts with the atypical, unreactive dienophile allyl alcohol. Our methodology gives access to unprecedented oxanorbornene derivatives in high chemo-, regio- and stereoselectivity, which can be readily diversified into valuable products. This offers the potential of scalable production of renewable chemical building blocks from cheap, bioderived platform molecules. [ABSTRACT FROM AUTHOR]
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- 2023
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9. Operando Spectroscopy of the Gas-Phase Aldol Condensation of Propanal over Solid Base Catalysts
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Hernández-Giménez, Ana M., Ruiz-Martínez, Javier, Puértolas, Begoña, Pérez-Ramírez, Javier, Bruijnincx, Pieter C. A., and Weckhuysen, Bert M.
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- 2017
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10. Expanding lignin thermal property space by fractionation and covalent modification.
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Riddell, Luke A., Enthoven, Floris J. P. A., Lindner, Jean-Pierre B., Meirer, Florian, and Bruijnincx, Pieter C. A.
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LIGNINS ,LIGNIN structure ,THERMAL properties ,GLASS transition temperature - Abstract
To fully exploit kraft lignin's potential in material applications, we need to achieve tight control over those key physicochemical lignin parameters that ultimately determine, and serve as proxy for, the properties of lignin-derived materials. Here, we show that fractionation combined with systematic (incremental) modification provides a powerful strategy to expand and controllably tailor lignin property space. In particular, the glass transition temperature (T
g ) of a typical kraft lignin could be tuned over a remarkable and unprecedented 213 °C. Remarkably, for all fractions the Tg proved to be highly linearly correlated with the degree of derivatisation by allylation, offering such tight control over the Tg of the lignin and ultimately the ability to 'dial-in' this key property. Importantly, such control over this proxy parameter indeed translated well to lignin-based thiol–ene thermosetting films, whose Tg s thus covered a range from 2–124 °C. This proof of concept suggests this approach to be a powerful and generalisable one, allowing a biorefinery or downstream operation to consciously and reliably tailor lignins to predictable specifications which fit their desired application. [ABSTRACT FROM AUTHOR]- Published
- 2023
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11. Reductive Partial Depolymerization of Acetone Organosolv Lignin to Tailor Lignin Molar Mass, Dispersity, and Reactivity for Polymer Applications.
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Smit, Arjan T., Dezaire, Thomas, Riddell, Luke A., and Bruijnincx, Pieter C. A.
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- 2023
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12. Targeting Valuable Chemical Commodities: Hydrazine‐mediated Diels‐Alder Aromatization of Biobased Furfurals.
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Cioc, Răzvan C., Crockatt, Marc, van der Waal, Jan C., and Bruijnincx, Pieter C. A.
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AROMATIZATION ,ACRYLIC acid ,FURFURAL ,HYDRAZONES ,RING formation (Chemistry) ,FURANS ,DIOLEFINS - Abstract
A hydrazine‐mediated approach towards renewable aromatics production via Diels‐Alder aromatization of readily available, biobased furfurals was explored as alterative to the more classical approaches that rely on reactive but uneconomical reduced dienes (e. g., 2,5‐dimethylfuran). To enable cycloaddition chemistry with these otherwise unreactive formyl furans, substrate activation by N,N‐dimethyl hydrazone formation was investigated. The choice of the reaction partner was key to the success of the transformation, and in this respect acrylic acid showed the most promising results in the synthesis of aromatics. This strategy allowed for selectivities up to 60 % for a complex transformation consisting of Diels‐Alder cycloaddition, oxabridge opening, decarboxylation, and dehydration. Exploration of the furfural scope yielded generic structure‐reactivity‐stability relationships. The proposed methodology enabled the redox‐efficient, operationally simple, and mild synthesis of renewable (p‐disubstituted) aromatics of commercial importance under remarkably mild conditions. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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13. Zinc complexes of the biomimetic N,N,O ligand family of substituted 3,3-bis(1-alkylimidazol-2-yl)propionates: the formation of oxalate from pyruvate
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Bruijnincx, Pieter C. A., Lutz, Martin, den Breejen, Johan P., Spek, Anthony L., van Koten, Gerard, and Klein Gebbink, Robertus J. M.
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- 2007
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14. The Seventeenth International Symposium on Relations Between Homogeneous and Heterogeneous Catalysis Utrecht July 12–15 2015
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Weckhuysen, Bert M., Bruijnincx, Pieter C. A., Lamers, Monique F. A., and Klein Gebbink, Robertus J. M.
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- 2016
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15. Biomass Pre-Extraction as a Versatile Strategy to Improve Biorefinery Feedstock Flexibility, Sugar Yields, and Lignin Purity.
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Smit, Arjan T., van Zomeren, André, Dussan, Karla, Riddell, Luke A., Huijgen, Wouter J. J., Dijkstra, Jan Wilco, and Bruijnincx, Pieter C. A.
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- 2022
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16. The Interplay between Kinetics and Thermodynamics in Furan Diels–Alder Chemistry for Sustainable Chemicals Production.
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Cioc, Răzvan C., Crockatt, Marc, van der Waal, Jan C., and Bruijnincx, Pieter C. A.
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DIELS-Alder reaction ,SUSTAINABLE chemistry ,THERMODYNAMICS ,RENEWABLE natural resources ,SUSTAINABILITY ,OPEN-ended questions - Abstract
Biomass‐derived furanic platform molecules have emerged as promising building blocks for renewable chemicals and functional materials. To this aim, the Diels–Alder (DA) cycloaddition stands out as a versatile strategy to convert these renewable resources in highly atom‐efficient ways. Despite nearly a century worth of examples of furan DA chemistry, clear structure–reactivity–stability relationships are still to be established. Detailed understanding of the intricate interplay between kinetics and thermodynamics in these very particular [4+2] cycloadditions is essential to push further development and truly expand the scope beyond the ubiquitous addend combinations of electron‐rich furans and electron‐deficient olefins. Herein, we provide pertinent examples of DA chemistry, taken from various fields, to highlight trends, establish correlations and answer open questions in the field with the aim to support future efforts in the sustainable chemicals and materials production. [ABSTRACT FROM AUTHOR]
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- 2022
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17. Monitoring Molecular Weight Changes during Technical Lignin Depolymerization by Operando Attenuated Total Reflectance Infrared Spectroscopy and Chemometrics.
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Khalili, Khaled N. M., de Peinder, Peter, Donkers, Jacqueline, Gosselink, Richard J. A., Bruijnincx, Pieter C. A., and Weckhuysen, Bert M.
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LIGNINS ,REFLECTANCE spectroscopy ,ATTENUATED total reflectance ,LIGNIN structure ,MOLECULAR weights ,DEPOLYMERIZATION ,GEL permeation chromatography ,CHEMOMETRICS - Abstract
Technical lignins are increasingly available at industrial scale, offering opportunities for valorization, such as by (partial) depolymerization. Any downstream lignin application requires careful tailoring of structural properties, such as molecular weight or functional group density, properties that are difficult to control or predict given the structure variability and recalcitrance of technical lignins. Online insight into changes in molecular weight (Mw), to gauge the extent of lignin depolymerization and repolymerization, would be highly desired to improve such control, but cannot be readily provided by the standard ex‐situ techniques, such as size exclusion chromatography (SEC). Herein, operando attenuated total reflectance infrared (ATR‐IR) spectroscopy combined with chemometrics provided temporal changes in Mw during lignin depolymerization with high resolution. More specifically, ex‐situ SEC‐derived Mw and polydispersity data of kraft lignin subjected to aqueous phase reforming conditions could be well correlated with ATR‐IR spectra of the reaction mixture as a function of time. The developed method showed excellent regression results and relative error, comparable to the standard SEC method. The method developed has the potential to be translated to other lignin depolymerization processes. [ABSTRACT FROM AUTHOR]
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- 2021
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18. Bifunctional Janus Silica Spheres for Pickering Interfacial Tandem Catalysis.
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Chang, Fuqiang, Vis, Carolien M., Bergmeijer, Menno, Howes, Stuart C., and Bruijnincx, Pieter C. A.
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CATALYSIS ,JANUS particles ,BASE catalysts ,PARAFFIN wax ,SPHERES ,FUSED salts - Abstract
Nature provides much inspiration for the design of multistep conversion processes, with numerous reactions running simultaneously and without interference in cells, for example. A key challenge in mimicking nature's strategies is to compartmentalize incompatible reagents and catalysts, for example, for tandem catalysis. Here, we present a new strategy for antagonistic catalyst compartmentalization. The synthesis of bifunctional Janus catalyst particles carrying acid and base groups on the particle's opposite patches is reported as is their application as acid‐base catalysts in oil/water emulsions. The synthesis strategy involved the use of monodisperse, hydrophobic and amine‐functionalized silica particles (SiO2−NH2−OSi(CH3)3) to prepare an oil‐in‐water Pickering emulsion (PE) with molten paraffin wax. After solidification, the exposed patch of the silica particles was selectively etched and refunctionalized with acid groups to yield acid‐base Janus particles (Janus A–B). These materials were successfully applied in biphasic Pickering interfacial catalysis for the tandem dehydration‐Knoevenagel condensation of fructose to 5‐(hydroxymethyl)furfural‐2‐diethylmalonate (5‐HMF‐DEM) in a water/4‐propylguaiacol PE. The results demonstrate the advantage of rapid extraction of 5‐hydroxymethylfurfural (5‐HMF), a prominent platform molecule prone to side product formation in acidic media. A simple strategy to tune the acid/base balance using PE with both Janus A–B and monofunctional SiO2−NH2−OSi(CH3)3 base catalysts proved effective for antagonistic tandem catalysis. [ABSTRACT FROM AUTHOR]
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- 2021
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19. Monitoring Aqueous Phase Reactions by Operando ATR‐IR Spectroscopy at High Temperature and Pressure: A Biomass Conversion Showcase.
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Khalili, Khaled N. M., de Peinder, Peter, Bruijnincx, Pieter C. A., and Weckhuysen, Bert M.
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SPECTROMETRY ,SPECTROSCOPIC imaging ,LIGNOCELLULOSE ,CATALYTIC activity ,BIOMASS conversion - Abstract
Spectroscopic insight into aqueous phase catalytic reactions under realistic conditions aids detailed understanding and fosters further improvements. However, this is also very challenging, particularly in the liquid phase, given the typically elevated temperatures and pressures employed. Here, we report an operando Attenuated Total Reflectance‐Infrared (ATR‐IR) spectroscopic method to monitor the Aqueous Phase Reforming (APR) of Kraft lignin at 225 °C and 30 bar over a Pt/Al2O3 catalyst. This is a showcase reaction, while the presented method developed is more generic. In addition to the high temperature and pressures conditions, spectral interference from bulk water is a major challenge. Other challenges include self‐absorption of IR light, molecular interactions, high substrate loadings and the noise resulting from water vapor and CO2. We present a protocol utilizing the temperature‐dependent single‐beam method to obtain high‐quality ATR‐IR spectra virtually free from temperature, background and matrix effects. The protocol allowed for effective correction for the aqueous solvent as a function of reaction temperature. A comparison with conventional spectral acquisition and correction shows the advantages of this approach. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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20. Furoic acid and derivatives as atypical dienes in Diels–Alder reactions.
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Cioc, Răzvan C., Smak, Tom J., Crockatt, Marc, van der Waal, Jan C., and Bruijnincx, Pieter C. A.
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DIELS-Alder reaction ,ACID derivatives ,DIOLEFINS ,RING formation (Chemistry) ,CHEMICAL synthesis ,DIENOPHILES ,FURFURAL - Abstract
The furan Diels–Alder (DA) cycloaddition reaction has become an important tool in green chemistry, being central to the sustainable synthesis of many chemical building blocks. The restriction to electron-rich furans is a significant limitation of the scope of suitable dienes, in particular hampering the use of the furans most readily obtained from biomass, furfurals and their oxidized variants, furoic acids. Herein, it is shown that despite their electron-withdrawing substituents, 2-furoic acids and derivatives (esters, amides) are in fact reactive dienes in Diels–Alder couplings with maleimide dienophiles. The reactions benefit from a substantial rate-enhancement when water is used as solvent, and from activation of the 2-furoic acids by conversion to the corresponding carboxylate salts. This approach enables Diels–Alder reactions to be performed under very mild conditions, even with highly unreactive dienes such as 2,5-furandicarboxylic acid. The obtained DA adducts of furoic acids are shown to be versatile synthons in the conversion to various saturated and aromatic carbocyclic products. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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21. Crystal Phase Effects on the Gas‐Phase Ketonization of Small Carboxylic Acids over TiO2 Catalysts.
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Fufachev, Egor V., Weckhuysen, Bert M., and Bruijnincx, Pieter C. A.
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PROPIONIC acid ,COUPLING reactions (Chemistry) ,CARBOXYLIC acids ,CARBOXYLATES ,MASS spectrometry ,FATTY acids ,CARBOXYLIC acid derivatives ,ACETIC acid - Abstract
The choice of TiO2 crystal phase (i. e., anatase, rutile, or brookite) greatly influences catalyst performance in the gas‐phase ketonization of small volatile fatty acids, such as acetic acid and propionic acid. Rutile TiO2 was found to perform best, combining superior activity, as exemplified by an exceptional reaction rate of 141.8 mmol h−1 gcat−1 (at 425 °C and 24 h−1) with excellent ketone selectivity when propionic acid was used. Brookite, to the best of our knowledge never reported before as a viable ketonization catalyst, was found to outperform the well‐studied anatase phase, but not rutile. Operando Fourier‐transform IR spectroscopy measurements combined with on‐line mass spectrometry showed that bidentate carboxylates were the most abundant surface species on the rutile and brookite surfaces, while on anatase both monodentate and bidentate carboxylates co‐existed. The bidendate carboxylates were thought to be precursors to the active ketonization species, likely monodentate intermediates more prone to C−C coupling. Ketonization activity did not directly correlate with acidity; the observed, strong crystal phase effect did suggest that ketonization activity is influenced strongly by geometrical factors that determine the ease of formation of the relevant surface intermediates. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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22. Structured hydroxyapatite composites as efficient solid base catalysts for condensation reactions.
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Jose, Tharun, Ftouni, Jamal, and Bruijnincx, Pieter C. A.
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- 2021
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23. Upscaling Effects on Alkali Metal‐Grafted Ultrastable Y Zeolite Extrudates for Modeled Catalytic Deoxygenation of Bio‐oils.
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Hernández‐Giménez, Ana M., Kort, Laura M., Whiting, Gareth T., Hernando, Héctor, Puértolas, Begoña, Pérez‐Ramírez, Javier, Serrano, David P., Bruijnincx, Pieter C. A., and Weckhuysen, Bert M.
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ZEOLITE Y ,ALDOL condensation ,DEOXYGENATION ,CONDENSATION reactions ,LEWIS acidity ,ALKALI metals ,ALKALI metal ions ,POTASSIUM ions - Abstract
Developing efficient solid catalysts is necessary when for example moving from batch chemistry to continuous flow systems. In this work, scale‐up effects of zeolite‐based catalyst materials have been tested in aldol condensation as a model reaction for bio‐oil upgrading via deoxygenation. For this purpose, shaped catalyst bodies were obtained via extrusion of ultrastable Y zeolite (USY) using either attapulgite (Att.) or bentonite (Bent.) as clay binder, followed by post‐alkali metal ion grafting of K+ after (rather than before) extrusion. This approach proved essential to preserve the catalysts' crystallinity. The Att.‐bound catalyst body was more active than its Bent.‐counterpart, correlating well with the observed changes in physicochemical properties. The K‐(USY/Att.) catalyst showed new basic oxygen and strong Lewis acidic sites resulting from clay incorporation, in addition to the Lewis acid (K+) and basic sites (K−OH) created upon grafting. For K‐(USY/Bent.), the grafting proved less efficient, likely due to pore blockage caused by the binder. Bent. addition resulted in acid sites of moderate Brønsted and strong Lewis acidity, but hardly any of the basicity desired for the aldol condensation reaction. The poor potassium grafting yet led to some cation exchange with the binder (likely with the Na+ naturally present in the Bent. material). The results obtained demonstrate the critical importance of the choice of the binder material and the synthesis protocol adopted for upscaling solid base materials in the form of catalyst bodies. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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24. Recent developments in catalysis with Pickering Emulsions.
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Chang, Fuqiang, Vis, Carolien M., Ciptonugroho, Wirawan, and Bruijnincx, Pieter C. A.
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CATALYSIS ,CHEMICAL systems ,EMULSIONS ,CHEMICAL amplification ,PHARMACEUTICAL industry ,ENCAPSULATION (Catalysis) - Abstract
Pickering emulsions (PEs), emulsions stabilized by solid emulsifiers, are already of great importance for the food, pharmaceutical and biomedical industry. More recently, PEs are also being increasingly used as advanced catalytic systems for green chemical transformations. These efforts aim to combine the green credentials of biphasic catalysis with the intrinsic advantages offered by PEs, which include increased stability and interfacial area. Here, we provide a review of the recent advances in the field of PE catalysis, emphasizing the developments in the design of (functional) solid stabilizing particles, the range of accessible catalytic reactions and reaction conditions, as well as advances in reactor engineering, such as the application of PE catalysis in continuous flow systems. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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25. Effect of Mesoporosity, Acidity and Crystal Size of Zeolite ZSM‐5 on Catalytic Performance during the Ex‐situ Catalytic Fast Pyrolysis of Biomass.
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Hernández‐Giménez, Ana M., Heracleous, Eleni, Pachatouridou, Eleni, Horvat, Andrej, Hernando, Héctor, Serrano, David P., Lappas, Angelos A., Bruijnincx, Pieter C. A., and Weckhuysen, Bert M.
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NANOCRYSTALS ,ZEOLITES ,BIOMASS ,ACIDITY ,CRYSTALS ,MESOPOROUS materials ,CATALYST poisoning - Abstract
The catalytic performance of a set of technical, zeolite ZSM‐5 extruded materials have been studied in a bench scale unit for the ex‐situ Catalytic Fast Pyrolysis (CFP) of lignocellulosic biomass. The set of catalysts include micro‐ and mesoporous materials, with and without ZrO2‐promotion, with different Si/Al ratios and with micro‐ and nanosized zeolite crystals. Mesoporosity, acidity and crystal size play a key role on the overall catalytic performances in terms of activity and selectivity (i. e., in their ability to obtain the highest bio‐oil fraction with the lowest oxygen content), and also importantly, stability. Detailed post‐mortem bulk and micro‐spectroscopic studies of the solid catalysts complement the catalytic testing. The obtained results point towards coke deposits as the main cause for catalyst deactivation. Details of the nature, formation and evolution of these coke deposits revealed essential insights, which serve to evaluate the design of catalysts for the ex‐situ CFP of biomass. In particular the mesoporous catalysts are overall better preserved with increasing time‐on‐stream and deactivate later than their microporous counterparts, which suffer from pore blockage. Likewise, it was seen that ZrO2‐promotion contributed positively in the prevention against deactivation by hard coke spreading, thanks to its enhanced Lewis acidity. The zeolite's crystal size is another important characteristic to combine the different components within catalyst bodies, ensuring the proper interaction between zeolite, promoter and binder. This is illustrated by the nanocrystalline ZrO2/n‐ZSM‐5‐ATP material, which shows the best catalytic performance. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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26. Catalytic Fast Pyrolysis of Biomass: Catalyst Characterization Reveals the Feed-Dependent Deactivation of a Technical ZSM-5-Based Catalyst.
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Luna-Murillo, Beatriz, Pala, Mehmet, Paioni, Alessandra Lucini, Baldus, Marc, Ronsse, Frederik, Prins, Wolter, Bruijnincx, Pieter C. A., and Weckhuysen, Bert M.
- Published
- 2021
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27. Direct Diels–Alder reactions of furfural derivatives with maleimides.
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Cioc, Răzvan C., Lutz, Martin, Pidko, Evgeny A., Crockatt, Marc, van der Waal, Jan C., and Bruijnincx, Pieter C. A.
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MALEIMIDES ,FURFURAL ,ORGANIC synthesis ,SUSTAINABLE buildings ,FURANS ,SUSTAINABLE chemistry ,DIELS-Alder reaction - Abstract
The Diels–Alder (DA) reaction of furans is a versatile tool in synthetic organic chemistry and in the production of sustainable building blocks and smart materials. Numerous experimental and theoretical investigations suggest that the diene scope is effectively limited to electron-rich furans, which excludes the most abundant and readily accessible renewable derivatives: furfural and its 5-hydroxymethyl homologue. Herein we show for the first time that electron-poor 2-formylfurans can also directly engage in Diels–Alder couplings. The key to success is the use of aqueous medium, which supplies an additional thermodynamic driving force by coupling the unfavorable DA equilibrium to the exergonic hydration of the carbonyl functionality in the adducts to form geminal diols. This finding enables the direct access to various novel DA adducts derived from renewable furfurals and maleimides, via a mild, simple and environmentally-friendly synthetic protocol. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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28. Dynamic Trapping as a Selective Route to Renewable Phthalide from Biomass‐Derived Furfuryl Alcohol.
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Lancefield, Christopher S., Fölker, Bart, Cioc, Razvan C., Stanciakova, Katarina, Bulo, Rosa E., Lutz, Martin, Crockatt, Marc, and Bruijnincx, Pieter C. A.
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FURFURYL alcohol ,TRAPPING ,SUSTAINABLE chemistry ,ACRYLATES ,ESTERS ,DIELS-Alder reaction - Abstract
A novel route for the production of the versatile chemical building block phthalide from biorenewable furfuryl alcohol and acrylate esters is presented. Two challenges that limit sustainable aromatics production via Diels–Alder (DA) aromatisation—an unfavourable equilibrium position and undesired regioselectivity when using asymmetric addends—were addressed using a dynamic kinetic trapping strategy. Activated acrylates were used to speed up the forward and reverse DA reactions, allowing for one of the four DA adducts to undergo a selective intramolecular lactonisation reaction in the presence of a weak base. The adduct is removed from the equilibrium pool, pulling the system completely to the product with a fixed, desired regiochemistry. A single 1,2‐regioisomeric lactone product was formed in up to 86 % yield and the acrylate activating agent liberated for reuse. The lactone was aromatised to give phthalide in almost quantitative yield in the presence of Ac2O and a catalytic amount of strong acid, or in 79 % using only catalytic acid. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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29. Continuous Flow Pickering Emulsion Catalysis in Droplet Microfluidics Studied with In Situ Raman Microscopy.
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Vis, Carolien M., Nieuwelink, Anne‐Eva, Weckhuysen, Bert M., and Bruijnincx, Pieter C. A.
- Subjects
CATALYSIS ,MICROFLUIDICS ,EMULSIONS ,RAMAN spectroscopy - Abstract
Pickering emulsions (PEs), emulsions stabilized by solid particles, have shown to be a versatile tool for biphasic catalysis. Here, we report a droplet microfluidic approach for flow PE (FPE) catalysis, further expanding the possibilities for PE catalysis beyond standard batch PE reactions. This microreactor allowed for the inline analysis of the catalytic process with in situ Raman spectroscopy, as demonstrated for the acid‐catalyzed deacetalization of benzaldehyde dimethyl acetal to form benzaldehyde. Furthermore, the use of the FPE system showed a nine fold improvement in yield compared to the simple biphasic flow system (FBS), highlighting the advantage of emulsification. Finally, FPE allowed an antagonistic set of reactions, the deacetalization–Knoevenagel condensation, which proved less efficient in FBS due to rapid acid‐base quenching. The droplet microfluidic system thus offers a versatile new extension of PE catalysis. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
30. Tandem catalytic aromatization of volatile fatty acids.
- Author
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Fufachev, Egor V., Weckhuysen, Bert M., and Bruijnincx, Pieter C. A.
- Subjects
NUCLEAR magnetic resonance spectroscopy ,COKE (Coal product) ,FATTY acids ,AROMATIZATION ,TOLUENE ,CATALYST structure ,INTERMEDIATE goods ,BRONSTED acids - Abstract
The transition towards a circular economy requires closing the carbon loop, e.g. by the development of new synthesis routes to valuable intermediates and products from organic-rich waste streams. Volatile fatty acids (VFA) can be fermentatively produced from wastewater and serve as circular platform chemicals. We show that these VFA can be catalytically upgraded to light aromatics (i.e., benzene, toluene, ethylbenzene and xylenes, BTEX) via a tandem catalytic reaction involving TiO
2 -catalyzed ketonization and zeolite ZSM-5 catalyzed aromatization. Including this intermediate ketonization step is demonstrated to be much more efficient than direct VFA aromatization, as direct acid conversion mainly gave rise to short-chain olefins by decarboxylation and low BTEX yields of 1%. A one-reactor, tandem catalytic conversion instead significantly improved the yield to 45% when zeolite Ga/ZSM-5 was used. Furthermore, the effect of VFA-derived ketone composition, a process parameter set by the fermentation process, on aromatics production efficiency and product distribution was found to be very pronounced for zeolite Ga/ZSM-5, but not for non-promoted zeolite HZSM-5. This suggests a different reaction mechanism to dominate on zeolite Ga/ZSM-5, involving dehydration on the Brønsted acid sites and cyclization/aromatization on the Ga sites. Finally, water, expected to be present in the feed during VFA upgrading, caused the activity of zeolite Ga/ZSM-5 to drop reversibly, but also led to lower coke buildup. Analysis of the spent catalyst with solid-state27 Al nuclear magnetic resonance spectroscopy and temperature-programmed reduction with H2 showed that the catalyst structure remained intact, also with water present in the feed. Together, the results demonstrate that catalytic ketonization/aromatization is an attractive circular approach for converting waste-derived carboxylic acids into renewable aromatics. [ABSTRACT FROM AUTHOR]- Published
- 2020
- Full Text
- View/download PDF
31. Influence of oxygenation on the reactivity of ruthenium-thiolato bonds in arene anticancer complexes: insights from XAS and DFT
- Author
-
Sriskandakumar, Thamayanthy, Petzold, Holm, Bruijnincx, Pieter C., Habtemariam, Abraha, Sadler, Peter J., and Kennepohl, Pierre
- Subjects
Density functionals -- Usage ,Organometallic compounds -- Structure ,Organometallic compounds -- Chemical properties ,Organometallic compounds -- Electric properties ,Ruthenium -- Chemical properties ,Ruthenium -- Atomic properties ,Thiols -- Chemical properties ,X-ray spectroscopy -- Usage ,Chemistry - Abstract
The nature of the Ru-S bond in the parent thiolato complexes and mono- (sulfenato) and bis- (sulfinato) oxygenated species including the affect of substituents on the sulfur and arene are compared. Sulfur K-edge XAS results have shown that [S.sub.3p] donation into the [Ru.sub.4d] manifold has depended on the oxidation state of the sulfur atom, whereas Ru K-edge data has shown little change at the metal center, and the DFT results have allowed a more detailed analysis of the electronic contributions to the Ru-S bond.
- Published
- 2009
32. High‐Yield 5‐Hydroxymethylfurfural Synthesis from Crude Sugar Beet Juice in a Biphasic Microreactor.
- Author
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Abdilla‐Santes, Ria M., Guo, Wenze, Bruijnincx, Pieter C. A., Yue, Jun, Deuss, Peter J., and Heeres, Hero J.
- Subjects
SUGAR beets ,SOLVENT extraction ,SUGAR manufacturing & refining ,MARKET prices ,RENEWABLE natural resources ,SUCROSE - Abstract
5‐Hydroxymethylfurfural (HMF) is an important biobased platform chemical obtainable in high selectivity by the hydrolysis of fructose (FRC). However, FRC is expensive, making the production of HMF at a competitive market price highly challenging. Here, it is shown that sugar beet thick juice, a crude, sucrose‐rich intermediate in sugar refining, is an excellent feedstock for HMF synthesis. Unprecedented high selectivities and yields of >90 % for HMF were achieved in a biphasic reactor setup at 150 °C using salted diluted thick juice with H2SO4 as catalyst and 2‐methyltetrahydrofuran as a bioderived extraction solvent. The conversion of glucose, obtained by sucrose inversion, could be limited to <10 mol %, allowing its recovery for further use. Interestingly, purified sucrose led to significantly lower HMF selectivity and yields, showing advantages from both an economic and chemical selectivity perspective. This opens new avenues for more cost‐effective HMF production. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
33. Zeolite-supported metal catalysts for selective hydrodeoxygenation of biomass-derived platform molecules.
- Author
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Luo, Wenhao, Cao, Wenxiu, Bruijnincx, Pieter C. A., Lin, Lu, Wang, Aiqin, and Zhang, Tao
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METAL catalysts ,ZEOLITE catalysts ,BIOMASS chemicals ,BRONSTED acids ,MOLECULAR models ,ZEOLITES - Abstract
Increasing demand for renewable chemicals and fuels has stimulated the search for alternative feedstocks and is driving the ongoing transition to a more renewables-based society. Considerable academic efforts have been directed at the valorisation of biomass sources and derived intermediates, so called platform molecules, to produce value-added chemicals and fuels. In this contribution, opportunities are discussed for the application of zeolite-supported bifunctional catalysts in the conversion of biomass sources into chemicals and fuels via hydrodeoxygenation (HDO). Such metal/zeolite catalyst systems play a prominent role in many of these biomass HDO routes. Emphasis is put on the current progress in metal/zeolite-catalysed HDO of three selected, promising routes involving biomass-derived platform molecules and the model compounds that mimic more complex feeds. Four key concepts of metal/zeolite catalysts, such as combining metal and Brønsted acid sites, site-ratio balancing, proximity between metal and acid functions and shape selectivity are discussed in order to provide a comprehensive overview. In addition, two challenges related to the accessibility of the active sites and catalyst stability in the liquid phase, typically a hot, highly polar, and protic reaction medium, are discussed. Finally, the open challenges and perspectives regarding the development of metal/zeolite catalysts for biomass HDO reactions are examined. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
34. Scaling‐Up of Bio‐Oil Upgrading during Biomass Pyrolysis over ZrO2/ZSM‐5‐Attapulgite.
- Author
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Hernando, Héctor, Hernández‐Giménez, Ana M., Gutiérrez‐Rubio, Santiago, Fakin, Tomaz, Horvat, Andrej, Danisi, Rosa M., Pizarro, Patricia, Fermoso, Javier, Heracleous, Eleni, Bruijnincx, Pieter C. A., Lappas, Angelos A., Weckhuysen, Bert M., and Serrano, David P.
- Subjects
LIGNOCELLULOSE ,ZEOLITE catalysts ,BIOMASS ,NUCLEAR magnetic resonance spectroscopy ,FLUORESCENCE microscopy ,PYROLYSIS - Abstract
Ex situ catalytic biomass pyrolysis was investigated at both laboratory and bench scale by using a zeolite ZSM‐5‐based catalyst for selectively upgrading the bio‐oil vapors. The catalyst consisted of nanocrystalline ZSM‐5, modified by incorporation of ZrO2 and agglomerated with attapulgite (ZrO2/n‐ZSM‐5‐ATP). Characterization of this material by means of different techniques, including CO2 and NH3 temperature‐programmed desorption (TPD), NMR spectroscopy, UV/Vis microspectroscopy, and fluorescence microscopy, showed that it possessed the right combination of accessibility and acid–base properties for promoting the conversion of the bulky molecules formed by lignocellulose pyrolysis and their subsequent deoxygenation to upgraded liquid organic fractions (bio‐oil). The results obtained at the laboratory scale by varying the catalyst‐to‐biomass ratio (C/B) indicated that the ZrO2/n‐ZSM‐5‐ATP catalyst was more efficient for bio‐oil deoxygenation than the parent zeolite n‐ZSM‐5, producing upgraded bio‐oils with better combinations of mass and energy yields with respect to the oxygen content. The excellent performance of the ZrO2/n‐ZSM‐5‐ATP system was confirmed by working with a continuous bench‐scale plant. The scale‐up of the process, even with different raw biomasses as the feedstock, reaction conditions, and operation modes, was in line with the laboratory‐scale results, leading to deoxygenation degrees of approximately 60 % with energy yields of approximately 70 % with respect to those of the thermal bio‐oil. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
35. Tandem Catalysis with Antagonistic Catalysts Compartmentalized in the Dispersed and Continuous Phases of a Pickering Emulsion.
- Author
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Vis, Carolien M., Smulders, Luc C. J., and Bruijnincx, Pieter C. A.
- Subjects
CATALYSIS ,BASE catalysts ,ACID catalysts ,CATALYSTS ,EMULSIONS ,BIFUNCTIONAL catalysis - Abstract
Tandem catalysis combines multiple conversion steps, catalysts, and reagents in one reaction medium, offering the potential to reduce waste and time. In this study, Pickering emulsions—emulsions stabilized by solid particles—are used as easy‐to‐prepare and bioinspired, compartmentalized reaction media for tandem catalysis. Making use of simple and inexpensive acid and base catalysts, the strategy of compartmentalization of two noncompatible catalysts in both phases of the emulsion is demonstrated by using the deacetalization–Knoevenagel condensation reaction of benzaldehyde dimethyl acetal as a probe reaction. In contrast to simple biphasic systems, which do not allow for tandem catalysis and show instantaneous quenching of the acid and base catalysts, the Pickering emulsions show efficient antagonistic tandem catalysis and give the desired product in high yield, as a result of an increased interfacial area and suppressed mutual destruction of the acid and base catalysts. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
36. Recovery and conversion of acetic acid from a phosphonium phosphinate ionic liquid to enable valorization of fermented wastewater.
- Author
-
Reyhanitash, Ehsan, Fufachev, Egor, van Munster, Kaspar D., van Beek, Michael B. M., Sprakel, Lisette M. J., Edelijn, Carmen N., Weckhuysen, Bert M., Kersten, Sascha R. A., Bruijnincx, Pieter C. A., and Schuur, Boelo
- Subjects
ACETIC acid ,IONIC liquids ,ISOTHERMAL titration calorimetry ,HYDROGEN bonding interactions ,CARBOXYLIC acids ,CYCLOTRIPHOSPHAZENES - Abstract
Production of volatile fatty acids (VFAs) by fermentation is a potential sustainable alternative for conventional petrochemical routes to VFAs. Due to the low VFA content of fermentation broths, robust and economical separation technology has to be devised to recover the VFA. Liquid–liquid extraction of VFAs with the phosphonium phosphinate ionic liquid (IL) [P
666,14 ][Phos] allows good VFA extractability. For an extraction process using [P666,14 ][Phos] to be green, it is essential to efficiently regenerate the solvent and recover the VFA. To obtain insight into the (strong) intermolecular interactions between [P666,14 ][Phos] and acetic acid, selected as a model VFA,1 H NMR,31 P NMR, FT-IR and isothermal titration calorimetry (ITC) were applied. The observations were used to interpret operations to recover acetic acid from the IL, which included evaporation at elevated temperature under vacuum, possibly assisted by nitrogen stripping, in situ esterification and back-extraction with volatile bases. Through evaporative regeneration with nitrogen stripping, HAc could be removed, but only down to an HAc/IL molar ratio of 1. The remaining molar equivalent of HAc–IL interacts tightly with the IL by partial proton transfer and strong hydrogen bonding interactions with the phosphinate anion. Back-extraction of HAc with trimethylamine (TMA) and subsequent decomposition of the HAc–TMA complexes allowed for successful IL regeneration. This process uses ten times less amine (TMA) than conventional amine-based extraction processes (e.g. tri-n-octyl amine), and provides a sustainable process route to obtain pure carboxylic acids from highly diluted aqueous solutions without generating large streams of byproducts. Further valorization via in-line vaporization/catalytic ketonization or via in-line thermal decomposition and ketonization of the TMA–HAc salt was also demonstrated, showing the potential of the VFAs as a green platform for bio-based chemicals. [ABSTRACT FROM AUTHOR]- Published
- 2019
- Full Text
- View/download PDF
37. Phase‐Dependent Stability and Substrate‐Induced Deactivation by Strong Metal‐Support Interaction of Ru/TiO2 Catalysts for the Hydrogenation of Levulinic Acid.
- Author
-
Liu, Fang, Ftouni, Jamal, Bruijnincx, Pieter C. A., and Weckhuysen, Bert M.
- Subjects
CATALYST poisoning ,RUTHENIUM catalysts ,TITANIUM dioxide ,HYDROGENATION ,KETONIC acids - Abstract
The choice of support type has a profound influence on catalyst performance in liquid phase hydrogenation reactions, including the catalytic hydrogenation of biomass‐derived levulinic acid (LA) to γ‐valerolactone (GVL). Catalytic performance, including stability, of three Ru/TiO2 catalysts, having a similar mean Ru metal nanoparticle size but supported on three types of TiO2, namely P25, rutile and anatase, is evaluated by multiple reuse under batch reactor conditions. T3he catalysts' physicochemical properties before and after recycling are characterized by XRD, STEM, TGA and FT‐IR after CO stepwise adsorption. The results show that the deactivation seen for (mixed) anatase‐supported catalysts in dioxane can be attributed to strong metal‐support interaction (SMSI) rather than coke formation or metal sintering, with the rutile‐based catalyst being more resistant against such support reduction. Notably, SMSI formation under the applied, relatively mild conditions only occurs in the presence of organic acids, such as LA or valeric acid. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
38. Linkage Abundance and Molecular Weight Characteristics of Technical Lignins by Attenuated Total Reflection‐FTIR Spectroscopy Combined with Multivariate Analysis.
- Author
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Lancefield, Christopher S., Constant, Sandra, de Peinder, Peter, and Bruijnincx, Pieter C. A.
- Subjects
LIGNINS ,NUCLEAR magnetic resonance spectroscopy ,MOLECULAR weights ,PARTIAL least squares regression ,ATTENUATED total reflectance ,MULTIVARIATE analysis ,GEL permeation chromatography - Abstract
Lignin is an attractive material for the production of renewable chemicals, materials and energy. However, utilization is hampered by its highly complex and variable chemical structure, which requires an extensive suite of analytical instruments to characterize. Here, we demonstrate that straightforward attenuated total reflection (ATR)‐FTIR analysis combined with principle component analysis (PCA) and partial least squares (PLS) modelling can provide remarkable insight into the structure of technical lignins, giving quantitative results that are comparable to standard gel‐permeation chromatography (GPC) and 2D heteronuclear single quantum coherence (HSQC) NMR methods. First, a calibration set of 54 different technical (fractionated) lignin samples, covering kraft, soda and organosolv processes, were prepared and analyzed using traditional GPC and NMR methods, as well as by readily accessible ATR‐FTIR spectroscopy. PLS models correlating the ATR‐FTIR spectra of the broad set of lignins with GPC and NMR measurements were found to have excellent coefficients of determination (R2 Cal.>0.85) for molecular weight (Mn, Mw) and inter‐unit abundances (β‐O‐4, β‐5 and β‐β), with low relative errors (6.2–14 %) as estimated from cross‐validation results. PLS analysis of a second set of 28 samples containing exclusively (fractionated) kraft lignins showed further improved prediction ability, with relative errors of 3.8–13 %, and the resulting model could predict the structural characteristics of an independent validation set of lignins with good accuracy. The results highlight the potential utility of this methodology for streamlining and expediting the often complex and time consuming technical lignin characterization process. One stop shop: The structural characterization of technical lignins is typically challenging, requiring extensive, high‐end instrumentation such as high‐field NMR spectrometers and gel permeation chromatography equipment. For routine analyses we show that attenuated total reflectance‐FTIR spectroscopy combined with chemometric approaches, especially partial least squares regression, can provide equivalent information on molecular weight and interunit abundances in a fraction of the time. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
39. Dichomitus squalens partially tailors its molecular responses to the composition of solid wood.
- Author
-
Daly, Paul, López, Sara Casado, Peng, Mao, Lancefield, Christopher S., Purvine, Samuel O., Kim, Young‐Mo, Zink, Erika M., Dohnalkova, Alice, Singan, Vasanth R., Lipzen, Anna, Dilworth, David, Wang, Mei, Ng, Vivian, Robinson, Errol, Orr, Galya, Baker, Scott E., Bruijnincx, Pieter C. A., Hildén, Kristiina S., Grigoriev, Igor V., and Mäkelä, Miia R.
- Subjects
POLYPORACEAE ,WOOD chemistry ,BIODEGRADATION ,SOFTWOOD ,NUCLEAR magnetic resonance spectroscopy - Abstract
Summary: White‐rot fungi, such as Dichomitus squalens, degrade all wood components and inhabit mixed‐wood forests containing both soft‐ and hardwood species. In this study, we evaluated how D. squalens responded to the compositional differences in softwood [guaiacyl (G) lignin and higher mannan content] and hardwood [syringyl/guaiacyl (S/G) lignin and higher xylan content] using semi‐natural solid cultures. Spruce (softwood) and birch (hardwood) sticks were degraded by D. squalens as measured by oxidation of the lignins using 2D‐NMR. The fungal response as measured by transcriptomics, proteomics and enzyme activities showed a partial tailoring to wood composition. Mannanolytic transcripts and proteins were more abundant in spruce cultures, while a proportionally higher xylanolytic activity was detected in birch cultures. Both wood types induced manganese peroxidases to a much higher level than laccases, but higher transcript and protein levels of the manganese peroxidases were observed on the G‐lignin rich spruce. Overall, the molecular responses demonstrated a stronger adaptation to the spruce rather than birch composition, possibly because D. squalens is mainly found degrading softwoods in nature, which supports the ability of the solid wood cultures to reflect the natural environment. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
40. Uniformly Oriented Zeolite ZSM‐5 Membranes with Tunable Wettability on a Porous Ceramic.
- Author
-
Fu, Donglong, Schmidt, Joel E., Pletcher, Paul, Karakiliç, Pelin, Ye, Xinwei, Vis, Carolien M., Bruijnincx, Pieter C. A., Filez, Matthias, Mandemaker, Laurens D. B., Winnubst, Louis, and Weckhuysen, Bert M.
- Subjects
SUBSTRATES (Materials science) ,SILICALITE ,CERAMICS ,WETTING ,PERMEATION tubes - Abstract
Abstract: Facile fabrication of well‐intergrown, oriented zeolite membranes with tunable chemical properties on commercially proven substrates is crucial to broadening their applications for separation and catalysis. Rationally determined electrostatic adsorption can enable the direct attachment of a b‐oriented silicalite‐1 monolayer on a commercial porous ceramic substrate. Homoepitaxially oriented, well‐intergrown zeolite ZSM‐5 membranes with a tunable composition of Si/Al=25–∞ were obtained by secondary growth of the monolayer. Intercrystallite defects can be eliminated by using Na
+ as the mineralizer to promote lateral crystal growth and suppress surface nucleation in the direction of the straight channels, as evidenced by atomic force microscopy measurements. Water permeation testing shows tunable wettability from hydrophobic to highly hydrophilic, giving the potential for a wide range of applications. [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
- View/download PDF
41. Identification of a diagnostic structural motif reveals a new reaction intermediate and condensation pathway in kraft lignin formation.
- Author
-
Lancefield, Christopher S., Wienk, Hans L. J., Boelens, Rolf, Weckhuysen, Bert M., and Bruijnincx, Pieter C. A.
- Published
- 2018
- Full Text
- View/download PDF
42. Engineering the acidity and accessibility of the zeolite ZSM-5 for efficient bio-oil upgrading in catalytic pyrolysis of lignocellulose.
- Author
-
Hernando, Héctor, Hernández-Giménez, Ana M., Ochoa-Hernández, Cristina, Bruijnincx, Pieter C. A., Houben, Klaartje, Baldus, Marc, Pizarro, Patricia, Coronado, Juan M., Fermoso, Javier, Čejka, Jiří, Weckhuysen, Bert M., and Serrano, David P.
- Subjects
ACIDITY ,ZEOLITES ,LIGNOCELLULOSE - Abstract
The properties of the zeolite ZSM-5 have been optimised for the production and deoxygenation of the bio-oil* (bio-oil on water-free basis) fraction by lignocellulose catalytic pyrolysis. Two ZSM-5 supports possessing high mesopore/external surface area, and therefore enhanced accessibility, have been employed to promote the conversion of the bulky compounds formed in the primary cracking of lignocellulose. These supports are a nanocrystalline material (n-ZSM-5) and a hierarchical sample (h-ZSM-5) of different Si/Al ratios and acid site concentrations. Acidic features of both zeolites have been modified and adjusted by incorporation of ZrO
2 , which has a significant effect on the concentration and distribution of both Brønsted and Lewis acid sites. These materials have been tested in the catalytic pyrolysis of acid-washed wheat straw (WS-ac) using a two-step (thermal/catalytic) reaction system at different catalyst/biomass ratios. The results obtained have been assessed in terms of oxygen content, energy yield and composition of the produced bio-oil*, taking also into account the selectivity towards the different deoxygenation pathways. The ZrO2 /n-ZSM-5 sample showed remarkable performance in the biomass catalytic pyrolysis, as a result of the appropriate combination of accessibility and acidic properties. In particular, modification of the zeolitic support acidity by incorporation of highly dispersed ZrO2 effectively decreased the extent of secondary reactions, such as severe cracking and coke formation, as well as promoted the conversion of the oligomers formed initially by lignocellulose pyrolysis, thus sharply decreasing the proportion of the components not detected by GC-MS in the upgraded bio-oil*. [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
- View/download PDF
43. Iridium-catalysed primary alcohol oxidation and hydrogen shuttling for the depolymerisation of lignin.
- Author
-
Lancefield, Christopher S., Teunissen, Lucas W., Weckhuysen, Bert M., and Bruijnincx, Pieter C. A.
- Subjects
ALCOHOL oxidation ,HYDROGEN ,LIGNINS - Abstract
Lignin is a potentially abundant renewable resource for the production of aromatic chemicals, however its selective depolymerisation is challenging. Here, we report a new catalytic system for the depolymerisation of lignin to novel, non-phenolic monoaromatic products based on the selective β-O-4 primary alcohol dehydrogenation with a Cp*Ir-bipyridonate catalyst complex under basic conditions. We show that this system is capable of promoting the depolymerisation of model compounds and isolated lignins via a sequence of selective primary alcohol dehydrogenation, retro-aldol (C
α –Cβ ) bond cleavage and in situ stabilisation of the aldehyde products by transfer (de)hydrogenation to alcohols and carboxylic acids. This method was found to give good to excellent yields of cleavage products with both etherified and free-phenolic lignin model compounds and could be applied to real lignin to generate a range of novel non-phenolic monomers including diols and di-acids. We additionally show, by using the same catalyst in a convergent, one-pot procedure, that these products can be selectively channelled towards a single di-acid product, giving much simpler product mixtures as a result. [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
- View/download PDF
44. Influence of Levulinic Acid Hydrogenation on Aluminum Coordination in Zeolite‐Supported Ruthenium Catalysts: A 27Al 3QMAS Nuclear Magnetic Resonance Study.
- Author
-
Luo, Wenhao, van Eck, Ernst R. H., Bruijnincx, Pieter C. A., and Weckhuysen, Bert M.
- Published
- 2018
- Full Text
- View/download PDF
45. Integrated Transmission Electron and Single-Molecule Fluorescence Microscopy Correlates Reactivity with Ultrastructure in a Single Catalyst Particle.
- Author
-
Hendriks, Frank C., Mohammadian, Sajjad, Ristanović, Zoran, Kalirai, Sam, Meirer, Florian, Vogt, Eelco T. C., Bruijnincx, Pieter C. A., Gerritsen, Hans C., and Weckhuysen, Bert M.
- Subjects
SINGLE molecules ,OLIGOMERIZATION ,REACTIVITY (Chemistry) ,STRUCTURE-activity relationships ,TRANSMISSION electron microscopy ,FLUORESCENCE microscopy - Abstract
Establishing structure-activity relationships in complex, hierarchically structured nanomaterials, such as fluid catalytic cracking (FCC) catalysts, requires characterization with complementary, correlated analysis techniques. An integrated setup has been developed to perform transmission electron microscopy (TEM) and single-molecule fluorescence (SMF) microscopy on such nanostructured samples. Correlated structure-reactivity information was obtained for 100 nm thin, microtomed sections of a single FCC catalyst particle using this novel SMF-TEM high-resolution combination. High reactivity in a thiophene oligomerization probe reaction correlated well with TEM-derived zeolite locations, while matrix components, such as clay and amorphous binder material, were found not to display activity. Differences in fluorescence intensity were also observed within and between distinct zeolite aggregate domains, indicating that not all zeolite domains are equally active. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
46. Single-Molecule Fluorescence Microscopy Reveals Local Diffusion Coefficients in the Pore Network of an Individual Catalyst Particle.
- Author
-
Hendriks, Frank C., Meirer, Florian, Kubarev, Alexey V., Ristanović, Zoran, Roeffaers, Maarten B. J., Vogt, Eelco T. C., Bruijnincx, Pieter C. A., and Weckhuysen, Bert M.
- Published
- 2017
- Full Text
- View/download PDF
47. Influence of Sulfuric Acid on the Performance of Ruthenium-based Catalysts in the Liquid-Phase Hydrogenation of Levulinic Acid to γ-Valerolactone.
- Author
-
Ftouni, Jamal, Genuino, Homer C., Muñoz‐Murillo, Ara, Bruijnincx, Pieter C. A., and Weckhuysen, Bert M.
- Subjects
RUTHENIUM catalysts ,SULFURIC acid ,LIQUID phase epitaxy ,HYDROGENATION ,CHEMICAL stability - Abstract
The presence of biogenic or process-derived impurities poses a major problem on the efficient catalytic hydrogenation of biomass-derived levulinic acid to γ-valerolactone; hence, studies on their influence on catalyst stability are now required. Herein, the influence of sulfuric acid as feed impurity on the performance of Ru-based heterogeneous catalysts, including Ru/ZrO
2 and mono- and bimetallic Ru-on-carbon catalysts in dioxane as solvent, was investigated. The carbon-supported Ru catalysts proved to be very sensitive to minor amounts of sulfuric acid. In stark contrast, Ru/ZrO2 showed a remarkable stability in the presence of the same impurity, which is attributed to the sulfate-ion adsorption capacity of the support. Preferential sulfate adsorption onto the surface of ZrO2 effectively protects the Ru active phase from deactivation by sulfur poisoning. A simple catalyst regeneration strategy was effective in removing adsorbed impurities, allowing efficient catalyst recycling. [ABSTRACT FROM AUTHOR]- Published
- 2017
- Full Text
- View/download PDF
48. Probing Zeolite Crystal Architecture and Structural Imperfections using Differently Sized Fluorescent Organic Probe Molecules.
- Author
-
Hendriks, Frank C., Schmidt, Joel E., Rombouts, Jeroen A., Lammertsma, Koop, Bruijnincx, Pieter C. A., and Weckhuysen, Bert M.
- Subjects
FLUORESCENT probes ,CRYSTAL structure ,CRYSTAL growth ,ZEOLITES ,MOLECULAR size ,POLARIZATION (Electrochemistry) - Abstract
A micro-spectroscopic method has been developed to probe the accessibility of zeolite crystals using a series of fluorescent 4-(4-diethylaminostyryl)-1-methylpyridinium iodide (DAMPI) probes of increasing molecular size. Staining large zeolite crystals with MFI (ZSM-5) topology and subsequent mapping of the resulting fluorescence using confocal fluorescence microscopy reveal differences in structural integrity: the 90° intergrowth sections of MFI crystals are prone to develop structural imperfections, which act as entrance routes for the probes into the zeolite crystal. Polarization-dependent measurements provide evidence for the probe molecule's alignment within the MFI zeolite pore system. The developed method was extended to BEA (Beta) crystals, showing that the previously observed hourglass pattern is a general feature of BEA crystals with this morphology. Furthermore, the probes can accurately identify at which crystal faces of BEA straight or sinusoidal pores open to the surface. The results show this method can spatially resolve the architecture-dependent internal pore structure of microporous materials, which is difficult to assess using other characterization techniques such as X-ray diffraction. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
49. Electronic and bite angle effects in catalytic C–O bond cleavage of a lignin model compound using ruthenium Xantphos complexes.
- Author
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Shaw, Luke, Somisara, D. M. Upulani K., How, Rebecca C., Westwood, Nicholas J., Bruijnincx, Pieter C. A., Weckhuysen, Bert M., and Kamer, Paul C. J.
- Published
- 2017
- Full Text
- View/download PDF
50. Selectivity Control in the Tandem Aromatization of Bio-Based Furanics Catalyzed by Solid Acids and Palladium.
- Author
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Genuino, Homer C., Thiyagarajan, Shanmugam, van der Waal, Jan C., de Jong, Ed, van Haveren, Jacco, van Es, Daan S., Weckhuysen, Bert M., and Bruijnincx, Pieter C. A.
- Subjects
DIELS-Alder reaction ,CHEMICAL reactions ,HYDROGENATION ,AROMATIZATION ,PALLADIUM - Abstract
Bio-based furanics can be aromatized efficiently by sequential Diels-Alder (DA) addition and hydrogenation steps followed by tandem catalytic aromatization. With a combination of zeolite H-Y and Pd/C, the hydrogenated DA adduct of 2-methylfuran and maleic anhydride can thus be aromatized in the liquid phase and, to a certain extent, decarboxylated to give high yields of the aromatic products 3-methylphthalic anhydride and o- and m-toluic acid. Here, it is shown that a variation in the acidity and textural properties of the solid acid as well as bifunctionality offers a handle on selectivity toward aromatic products. The zeolite component was found to dominate selectivity. Indeed, a linear correlation is found between 3-methylphthalic anhydride yield and the product of (strong acid/total acidity) and mesopore volume of H-Y, highlighting the need for balanced catalyst acidity and porosity. The efficient coupling of the dehydration and dehydrogenation steps by varying the zeolite-to-Pd/C ratio allowed the competitive decarboxylation reaction to be effectively suppressed, which led to an improved 3-methylphthalic anhydride/total aromatics selectivity ratio of 80 % (89 % total aromatics yield). The incorporation of Pd nanoparticles in close proximity to the acid sites in bifunctional Pd/H-Y catalysts also afforded a flexible means to control aromatic products selectivity, as further demonstrated in the aromatization of hydrogenated DA adducts from other diene/dienophile combinations. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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