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Laporte AAH, Masson TM, Zondag SDA, Noël T. Multiphasic Continuous-Flow Reactors for Handling Gaseous Reagents in Organic Synthesis: Enhancing Efficiency and Safety in Chemical Processes. Angew Chem Int Ed Engl 2024; 63:e202316108. [PMID: 38095968 DOI: 10.1002/anie.202316108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Indexed: 12/29/2023]
Abstract
The use of reactive gaseous reagents for the production of active pharmaceutical ingredients (APIs) remains a scientific challenge due to safety and efficiency limitations. The implementation of continuous-flow reactors has resulted in rapid development of gas-handling technology because of several advantages such as increased interfacial area, improved mass- and heat transfer, and seamless scale-up. This technology enables shorter and more atom-economic synthesis routes for the production of pharmaceutical compounds. Herein, we provide an overview of literature from 2016 onwards in the development of gas-handling continuous-flow technology as well as the use of gases in functionalization of APIs.
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Affiliation(s)
- Annechien A H Laporte
- Flow Chemistry Group, van't Hoff Institute for Molecular Sciences (HIMS), Universiteit van Amsterdam (UvA), Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Tom M Masson
- Flow Chemistry Group, van't Hoff Institute for Molecular Sciences (HIMS), Universiteit van Amsterdam (UvA), Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Stefan D A Zondag
- Flow Chemistry Group, van't Hoff Institute for Molecular Sciences (HIMS), Universiteit van Amsterdam (UvA), Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Timothy Noël
- Flow Chemistry Group, van't Hoff Institute for Molecular Sciences (HIMS), Universiteit van Amsterdam (UvA), Science Park 904, 1098 XH, Amsterdam, The Netherlands
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2
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Brewer A, Reicher C, Manatschal O, Bai H, Nakanishi K, Kleitz F. Powdered Hierarchically Porous Silica Monoliths for the Selective Extraction of Scandium. ACS SUSTAINABLE CHEMISTRY & ENGINEERING 2023; 11:15432-15439. [PMID: 37886037 PMCID: PMC10598872 DOI: 10.1021/acssuschemeng.3c04672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 09/19/2023] [Indexed: 10/28/2023]
Abstract
Scandium (Sc) is a high value Critical Material that is most commonly used in advanced alloys. Due to current and potential supply limitations, there has been an international effort to find new and improved ways to extract Sc from existing and novel resources. Solid-phase extraction (SPE) is one promising approach for Sc recovery, particularly for use with low-grade feedstocks. Here, unfunctionalized, powdered hierarchically porous silica monoliths from DPS Inc. (DPS) are used for Sc extraction in batch and semicontinuous flow systems at model conditions. The sorbent exhibits excellent mass transfer properties, much like the whole monoliths, which should permit Sc to be rapidly recovered from large volumes of feedstock. The Sc adsorption capacity of the material is ∼142.7 mg/g at pH 6, dropping to ∼12.0 mg/g at pH 3, and adsorption is furthermore highly selective for Sc compared with the other rare earth elements (REEs). Under semicontinuous flow conditions, recovery efficiency is limited by a kinetic process. The primary mechanism responsible for the system's slow approach to equilibrium is the Sc adsorption reaction kinetics rather than inter- or intraparticle diffusion. Overall, this unmodified hierarchically porous silica powder from DPS shows great promise for the selective extraction of Sc from various feedstocks.
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Affiliation(s)
- Aaron Brewer
- Department
of Functional Materials and Catalysis, Faculty of Chemistry, University of Vienna, 1090 Vienna, Austria
| | - Chloé Reicher
- Department
of Functional Materials and Catalysis, Faculty of Chemistry, University of Vienna, 1090 Vienna, Austria
| | - Olivia Manatschal
- Department
of Functional Materials and Catalysis, Faculty of Chemistry, University of Vienna, 1090 Vienna, Austria
| | | | - Kazuki Nakanishi
- Institute
of Materials and Systems for Sustainability, Nagoya University, 464-8601 Nagoya, Japan
- Institute
for Integrated Cell-Material Sciences, Kyoto
University, 606-8501 Kyoto, Japan
| | - Freddy Kleitz
- Department
of Functional Materials and Catalysis, Faculty of Chemistry, University of Vienna, 1090 Vienna, Austria
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3
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Owusu Prempeh C, Hartmann I, Formann S, Eiden M, Neubauer K, Atia H, Wotzka A, Wohlrab S, Nelles M. Comparative Study of Commercial Silica and Sol-Gel-Derived Porous Silica from Cornhusk for Low-Temperature Catalytic Methane Combustion. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:nano13091450. [PMID: 37176995 PMCID: PMC10180291 DOI: 10.3390/nano13091450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 04/17/2023] [Accepted: 04/21/2023] [Indexed: 05/15/2023]
Abstract
The synthesis and characterization of sol-gel-derived cornhusk support for low-temperature catalytic methane combustion (LTCMC) were investigated in this study. The prepared cornhusk support was impregnated with palladium and cerium oxide (Pd/CeO2) via the classical incipient wetness method. The resulting catalyst was characterized using various techniques, including X-ray diffraction (XRD), N2 physisorption (BET), transmission electron microscopy (TEM), and hydrogen temperature-programmed reduction (H2-TPR). The catalytic performance of the Pd/CeO2/CHSiO2 catalyst was evaluated for methane combustion in the temperature range of 150-600 °C using a temperature-controlled catalytic flow reactor, and its performance was compared with a commercial catalyst. The results showed that the Pd/CeO2 dispersed on SiO2 from the cornhusk ash support (Pd/CeO2/CHSiO2) catalyst exhibited excellent catalytic activity for methane combustion, with a conversion of 50% at 394 °C compared with 593 °C for the commercial silica catalyst (Pd/CeO2/commercial). Moreover, the Pd/CeO2/CHSiO2 catalyst displayed better catalytic stability after 10 h on stream, with a 7% marginal loss in catalytic activity compared with 11% recorded for the Pd/CeO2/commercial catalyst. The N2 physisorption and H2-TPR results indicated that the cornhusk SiO2 support possessed a higher surface area and strong reducibility than the synthesized commercial catalyst, contributing to the enhanced catalytic activity of the Pd/CeO2/SiO2 catalyst. Overall, the SiO2 generated from cornhusk ash exhibited promising potential as a low-cost and environmentally friendly support for LTCMC catalysts.
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Affiliation(s)
- Clement Owusu Prempeh
- Department of Thermochemical Conversion, DBFZ-Deutsches Biomasseforschungszentrum Gemeinnützige GmbH, Torgauer Straße 116, 04347 Leipzig, Germany
- Department of Agriculture and Environmental Science, University of Rostock, Justus-von-Liebig-Weg 6, 18059 Rostock, Germany
| | - Ingo Hartmann
- Department of Thermochemical Conversion, DBFZ-Deutsches Biomasseforschungszentrum Gemeinnützige GmbH, Torgauer Straße 116, 04347 Leipzig, Germany
| | - Steffi Formann
- Department of Thermochemical Conversion, DBFZ-Deutsches Biomasseforschungszentrum Gemeinnützige GmbH, Torgauer Straße 116, 04347 Leipzig, Germany
| | - Manfred Eiden
- Department of Thermochemical Conversion, DBFZ-Deutsches Biomasseforschungszentrum Gemeinnützige GmbH, Torgauer Straße 116, 04347 Leipzig, Germany
| | - Katja Neubauer
- Leibniz-Institute for Catalysis e.V. (LIKAT), Albert-Einstein-Str. 29a, 18059 Rostock, Germany
| | - Hanan Atia
- Leibniz-Institute for Catalysis e.V. (LIKAT), Albert-Einstein-Str. 29a, 18059 Rostock, Germany
| | - Alexander Wotzka
- Leibniz-Institute for Catalysis e.V. (LIKAT), Albert-Einstein-Str. 29a, 18059 Rostock, Germany
| | - Sebastian Wohlrab
- Leibniz-Institute for Catalysis e.V. (LIKAT), Albert-Einstein-Str. 29a, 18059 Rostock, Germany
| | - Michael Nelles
- Department of Thermochemical Conversion, DBFZ-Deutsches Biomasseforschungszentrum Gemeinnützige GmbH, Torgauer Straße 116, 04347 Leipzig, Germany
- Department of Agriculture and Environmental Science, University of Rostock, Justus-von-Liebig-Weg 6, 18059 Rostock, Germany
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Drying of Hierarchically Organized Porous Silica Monoliths-Comparison of Evaporative and Supercritical Drying. Gels 2023; 9:gels9010071. [PMID: 36661837 PMCID: PMC9858606 DOI: 10.3390/gels9010071] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 01/10/2023] [Accepted: 01/11/2023] [Indexed: 01/18/2023] Open
Abstract
In this study, we present a detailed comparison between a conventional supercritical drying process and an evaporative drying technique for hierarchically organized porous silica gel monoliths. These gels are based on a model system synthesized by the aqueous sol-gel processing of an ethylene-glycol-modified silane, resulting in a cellular, macroporous, strut-based network comprising anisotropic, periodically arranged mesopores formed by microporous amorphous silica. The effect of the two drying procedures on the pore properties (specific surface area, pore volume, and pore widths) and on the shrinkage of the monolith is evaluated through a comprehensive characterization by using nitrogen physisorption, electron microscopy, and small-angle X-ray scattering. It can clearly be demonstrated that for the hierarchically organized porous solids, the evaporative drying procedure can compete without the need for surface modification with the commonly applied supercritical drying in terms of the material and textural properties, such as specific surface area and pore volume. The thus obtained materials deliver a high specific surface area and exhibit overall comparable or even improved pore characteristics to monoliths prepared by supercritical drying. Additionally, the pore properties can be tailored to some extent by adjusting the drying conditions, such as temperature.
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Milborne B, Murrell L, Cardillo-Zallo I, Titman J, Briggs L, Scotchford C, Thompson A, Layfield R, Ahmed I. Developing Porous Ortho- and Pyrophosphate-Containing Glass Microspheres; Structural and Cytocompatibility Characterisation. Bioengineering (Basel) 2022; 9:611. [PMID: 36354522 PMCID: PMC9687370 DOI: 10.3390/bioengineering9110611] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 10/11/2022] [Accepted: 10/17/2022] [Indexed: 04/04/2024] Open
Abstract
Phosphate-based glasses (PBGs) are promising materials for bone repair and regeneration as they can be formulated to be compositionally similar to the inorganic components of bone. Alterations to the PBG formulation can be used to tailor their degradation rates and subsequent release of biotherapeutic ions to induce cellular responses, such as osteogenesis. In this work, novel invert-PBGs in the series xP2O5·(56 - x)CaO·24MgO·20Na2O (mol%), where x is 40, 35, 32.5 and 30 were formulated to contain pyro (Q1) and orthophosphate (Q0) species. These PBGs were processed into highly porous microspheres (PMS) via flame spheroidisation, with ~68% to 75% porosity levels. Compositional and structural analysis using EDX and 31P-MAS NMR revealed that significant depolymerisation occurred with reducing phosphate content which increased further when PBGs were processed into PMS. A decrease from 50% to 0% in Q2 species and an increase from 6% to 35% in Q0 species was observed for the PMS when the phosphate content decreased from 40 to 30 mol%. Ion release studies also revealed up to a four-fold decrease in cations and an eight-fold decrease in phosphate anions released with decreasing phosphate content. In vitro bioactivity studies revealed that the orthophosphate-rich PMS had favourable bioactivity responses after 28 days of immersion in simulated body fluid (SBF). Indirect and direct cell culture studies confirmed that the PMS were cytocompatible and supported cell growth and proliferation over 7 days of culture. The P30 PMS with ~65% pyro and ~35% ortho phosphate content revealed the most favourable properties and is suggested to be highly suitable for bone repair and regeneration, especially for orthobiologic applications owing to their highly porous morphology.
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Affiliation(s)
- Ben Milborne
- Advanced Materials Research Group, Faculty of Engineering, University of Nottingham, Nottingham NG7 2RD, UK
| | - Lauren Murrell
- Advanced Materials Research Group, Faculty of Engineering, University of Nottingham, Nottingham NG7 2RD, UK
| | | | - Jeremy Titman
- School of Chemistry, University of Nottingham, Nottingham NG7 2RD, UK
| | - Louise Briggs
- Advanced Materials Research Group, Faculty of Engineering, University of Nottingham, Nottingham NG7 2RD, UK
| | - Colin Scotchford
- Advanced Materials Research Group, Faculty of Engineering, University of Nottingham, Nottingham NG7 2RD, UK
| | - Alexander Thompson
- Biodiscovery Institute, Division of Cancer and Stem Cells, University of Nottingham, Nottingham NG7 2RD, UK
| | - Robert Layfield
- School of Life Sciences, Faculty of Medicine and Health Sciences, University of Nottingham, Nottingham NG7 2UH, UK
| | - Ifty Ahmed
- Advanced Materials Research Group, Faculty of Engineering, University of Nottingham, Nottingham NG7 2RD, UK
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Schneider D, Hwang S, Haase J, Miersemann E, Kärger J. Quantitating Diffusion Enhancement in Pore Hierarchies. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:11565-11572. [PMID: 36107750 DOI: 10.1021/acs.langmuir.2c01157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
A microporous continuum traversed by a set of mutually perpendicular channels is considered to be a model for a hierarchically porous system of the mesoporous zeolite type. Transient profiles of molecular uptake as determined by kinetic Monte Carlo (kMC) simulation are found to be in excellent agreement with the result attained by the application of the two-region model (the Kärger model) of molecular diffusion. In particular, it is found that, in the two limiting cases referred to as fast exchange and slow exchange, there exist two simple analytical expressions for the rate of molecular uptake and hence for the quantification of transport enhancement in comparison with the purely microporous adsorbent. In the general case, transport enhancement is simply recognized by the reciprocal addition of the expressions in the two limiting cases.
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Affiliation(s)
- D Schneider
- Innovation Center Computer Assisted Surgery (ICCAS), Institute at the Medical Faculty, Leipzig University, Semmelweisstraße 14, 04103 Leipzig, Germany
| | - S Hwang
- Faculty of Physics and Earth Sciences, Leipzig University, Linnéstrasse 5, 04103 Leipzig, Germany
| | - J Haase
- Faculty of Physics and Earth Sciences, Leipzig University, Linnéstrasse 5, 04103 Leipzig, Germany
- Saxon Academy of Sciences and Humanities in Leipzig, Structural Commission "Propagation in Nature, Technology and Society" 04107 Leipzig, Karl-Tauchnitz-Straße 1, Germany
| | - E Miersemann
- Saxon Academy of Sciences and Humanities in Leipzig, Structural Commission "Propagation in Nature, Technology and Society" 04107 Leipzig, Karl-Tauchnitz-Straße 1, Germany
- Faculty of Mathematics and Informatics, Leipzig University, Augustusplatz 10, 04109 Leipzig, Germany
| | - J Kärger
- Faculty of Physics and Earth Sciences, Leipzig University, Linnéstrasse 5, 04103 Leipzig, Germany
- Saxon Academy of Sciences and Humanities in Leipzig, Structural Commission "Propagation in Nature, Technology and Society" 04107 Leipzig, Karl-Tauchnitz-Straße 1, Germany
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7
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Jatoi HUK, Goepel M, Poppitz D, Kohns R, Enke D, Hartmann M, Gläser R. Mass Transfer in Hierarchical Silica Monoliths Loaded With Pt in the Continuous-Flow Liquid-Phase Hydrogenation of p-Nitrophenol. FRONTIERS IN CHEMICAL ENGINEERING 2021. [DOI: 10.3389/fceng.2021.789416] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Sol-gel-based silica monoliths with hierarchical mesopores/macropores are promising catalyst support and flow reactors. Here, we report the successful preparation of cylindrically shaped Pt-loaded silica monoliths (length: 2 cm, diameter: 0.5 cm) with a variable mean macropore width of 1, 6, 10, or 27 μm at a fixed mean mesopore width of 17 nm. The Pt-loaded monolithic catalysts were housed in a robust cladding made of borosilicate glass for use as a flow reactor. The monolithic reactors exhibit a permeability as high as 2 μm2 with a pressure drop below 9 bars over a flow rate range of 2–20 cm3 min−1 (solvent: water). The aqueous-phase hydrogenation of p-nitrophenol to p-aminophenol with NaBH4 as a reducing agent was used as a test reaction to study the influence of mass transfer on catalytic activity in continuous flow. No influence of flow rate on conversion at a fixed contact time of 2.6 s was observed for monolithic catalysts with mean macropore widths of 1, 10, or 27 µm. As opposed to earlier studies conducted at much lower flow velocities, this strongly indicates the absence of external mass-transfer limitations or stagnant layer formation in the macropores of the monolithic catalysts.
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8
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Medinger J, Nedyalkova M, Furlan M, Lüthi T, Hofmann J, Neels A, Lattuada M. Preparation and Machine-Learning Methods of Nacre-like Composites from the Self-Assembly of Magnetic Colloids Exposed to Rotating Magnetic Fields. ACS APPLIED MATERIALS & INTERFACES 2021; 13:48040-48052. [PMID: 34597504 DOI: 10.1021/acsami.1c13324] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Composite materials designed by nature, such as nacre, can display unique mechanical properties and have therefore been often mimicked by scientists. In this work, we prepared composite materials mimicking the nacre structure in two steps. First, we synthesized a silica gel skeleton with a layered structure using a bottom-up approach by modifying a sol-gel synthesis. Magnetic colloids were added to the sol solution, and a rotating magnetic field was applied during the sol-gel transition. When exposed to a rotating magnetic field, magnetic colloids organize in layers parallel to the plane of rotation of the field and template the growing silica phase, resulting in a layered anisotropic silica network mimicking the nacre's inorganic phase. Heat treatment has been applied to further harden the silica monoliths. The final nacre-inspired composite is created by filling the porous structure with a monomer, leading to a soft elastomer upon polymerization. Compression tests of the platelet-structured composite show that the mechanical properties of the nacre-like composite material far exceed those of nonstructured composite materials with an identical chemical composition. Increased toughness and a nearly 10-fold increase in Young's modulus were achieved. The natural brittleness and low elastic deformation of silica monoliths could be overcome by mimicking the natural architecture of nacre. Pattern recognition obtained with a classification of machine learning algorithms was applied to achieve a better understanding of the physical and chemical parameters that have the highest impact on the mechanical properties of the monoliths. Multivariate statistical analysis was performed to show that the structural control and the heat treatment have a very strong influence on the mechanical properties of the monoliths.
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Affiliation(s)
- Joelle Medinger
- Department of Chemistry, University of Fribourg, Chemin du Musée 9, CH-1700 Fribourg, Switzerland
| | - Miroslava Nedyalkova
- Department of Chemistry, University of Fribourg, Chemin du Musée 9, CH-1700 Fribourg, Switzerland
| | - Marco Furlan
- Department of Chemistry, University of Fribourg, Chemin du Musée 9, CH-1700 Fribourg, Switzerland
- eCO2 SA, Via Brüsighell 6, 6807 Taverne, Switzerland
| | - Thomas Lüthi
- Center for X-ray Analytics, Empa, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland
| | - Jürgen Hofmann
- Center for X-ray Analytics, Empa, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland
| | - Antonia Neels
- Department of Chemistry, University of Fribourg, Chemin du Musée 9, CH-1700 Fribourg, Switzerland
- Center for X-ray Analytics, Empa, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland
| | - Marco Lattuada
- Department of Chemistry, University of Fribourg, Chemin du Musée 9, CH-1700 Fribourg, Switzerland
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Turke K, Meinusch R, Cop P, Prates da Costa E, Brand RD, Henss A, Schreiner PR, Smarsly BM. Amine-Functionalized Nanoporous Silica Monoliths for Heterogeneous Catalysis of the Knoevenagel Condensation in Flow. ACS OMEGA 2021; 6:425-437. [PMID: 33458494 PMCID: PMC7807742 DOI: 10.1021/acsomega.0c04857] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 12/07/2020] [Indexed: 06/12/2023]
Abstract
Porous carrier materials functionalized with organocatalysts offer substantial advantages compared to homogeneous catalysts, e.g., easy separation of the catalyst, scalability, and an improved implementation in continuous operations. Here, we report the immobilization of (3-aminopropyl)trimethoxysilane (APTMS) onto self-prepared silica monoliths and its application as a heterogeneous catalyst in the Knoevenagel condensation between cyano ethylacetate and various aromatic aldehydes under continuous-flow conditions. The meso-macroporous silica monoliths (6-7 cm in length) were optimized to be used in flow taking advantage of their hierarchical meso- and macroporosity. The monoliths were cladded with a poly(ether ether ketone) (PEEK) tube by a refined procedure to guarantee tight connection between the carrier material and PEEK. Functionalization of the bare silica monoliths consisting of APTMS can be efficiently performed in flow in ethanol and toluene. While a large grafting gradient is obtained for toluene, the grafting in ethanol proceeds homogenously throughout the monolith, as evidenced by elemental analysis and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The silica monoliths exhibit high conversion up to 95% with concurrent low back pressures, which is of importance in flow catalysis. By connecting two monoliths, high conversions can be maintained for several flow rates. Two types of monoliths were synthesized, possessing different mesopore sizes. The monolith bearing the larger mesopore size showed an enhanced turnover frequency (TOF), while the monolith with the smaller mesopores allowed for larger quantities of the product to be synthesized, due to the higher surface area. A long-term stability test showed that the functionalized monoliths were still active after 66 h of continuous usage, while the overall yield decreased over time.
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Affiliation(s)
- Kevin Turke
- Institute
of Physical Chemistry, Justus Liebig University
Giessen, Heinrich-Buff-Ring 17, D-35392 Giessen, Germany
- Center
for Materials Research, Heinrich-Buff-Ring 16, D-35392 Giessen, Germany
| | - Rafael Meinusch
- Institute
of Physical Chemistry, Justus Liebig University
Giessen, Heinrich-Buff-Ring 17, D-35392 Giessen, Germany
- Center
for Materials Research, Heinrich-Buff-Ring 16, D-35392 Giessen, Germany
| | - Pascal Cop
- Institute
of Physical Chemistry, Justus Liebig University
Giessen, Heinrich-Buff-Ring 17, D-35392 Giessen, Germany
- Center
for Materials Research, Heinrich-Buff-Ring 16, D-35392 Giessen, Germany
| | - Eric Prates da Costa
- Institute
of Physical Chemistry, Justus Liebig University
Giessen, Heinrich-Buff-Ring 17, D-35392 Giessen, Germany
- Center
for Materials Research, Heinrich-Buff-Ring 16, D-35392 Giessen, Germany
| | - Raoul D. Brand
- Institute
of Physical Chemistry, Justus Liebig University
Giessen, Heinrich-Buff-Ring 17, D-35392 Giessen, Germany
- Center
for Materials Research, Heinrich-Buff-Ring 16, D-35392 Giessen, Germany
| | - Anja Henss
- Institute
of Physical Chemistry, Justus Liebig University
Giessen, Heinrich-Buff-Ring 17, D-35392 Giessen, Germany
- Center
for Materials Research, Heinrich-Buff-Ring 16, D-35392 Giessen, Germany
| | - Peter R. Schreiner
- Institute
of Organic Chemistry, Justus Liebig University
Giessen, Heinrich-Buff-Ring 17, D-35392 Giessen, Germany
- Center
for Materials Research, Heinrich-Buff-Ring 16, D-35392 Giessen, Germany
| | - Bernd M. Smarsly
- Institute
of Physical Chemistry, Justus Liebig University
Giessen, Heinrich-Buff-Ring 17, D-35392 Giessen, Germany
- Center
for Materials Research, Heinrich-Buff-Ring 16, D-35392 Giessen, Germany
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Abstract
AbstractLabeling in diffusion measurements by pulsed field gradient (PFG) NMR is based on the observation of the phase of nuclear spins acquired in a constant magnetic field with purposefully superimposed field gradients. This labeling does in no way affect microdynamics and provides information about the probability distribution of molecular displacements as a function of time. An introduction of the measuring principle is followed by a detailed description of the ranges of measurements and their limitation. Particular emphasis is given to an explanation of possible pitfalls in the measurements and the ways to circumvent them. Showcases presented for illustrating the wealth of information provided by PFG NMR include a survey on the various patterns of concentration dependence of intra-particle diffusion and examples of transport inhibition by additional transport resistances within the nanoporous particles and on their external surface. The latter information is attained by combination with the outcome of tracer exchange experiments, which are shown to become possible via a special formalism of PFG NMR data analysis. Further evidence provided by PFG NMR concerns diffusion enhancement in pore hierarchies, diffusion anisotropy and the impact of diffusion on chemical conversion in porous catalysts. A compilation of the specifics of PFG NMR and of the parallels with other measurement techniques concludes the paper.
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12
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Chmelik C, Gläser R, Haase J, Hwang S, Kärger J. Application of microimaging to diffusion studies in nanoporous materials. ADSORPTION 2020. [DOI: 10.1007/s10450-020-00279-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
AbstractMicroimaging on the basis of, respectively, interference microscopy and IR microscopy permit the observation of the distribution of guest molecules in nanoporous solids and their variation with time. Thus attainable knowledge of both concentration gradients and diffusion fluxes provides direct access to the underlying diffusion phenomena. This includes, in particular, the measurement of transport diffusion under transient, i. e. under non-equilibrium conditions, and of self- or tracer diffusion on considering the rate of tracer exchange. Correlating the difference in guest concentration close to the external surface to its equilibrium value with the influx into the nanoporous solid, microimaging does as well allow the direct determination of surface resistances. Examples illustrating the variety of information thus attainable include the comparison of mass transfer under equilibrium and non-equilibrium conditions, single- and multicomponent diffusion and chemical reactions. They, finally, introduce into the potentials of microimaging for an in-depth study of mass transfer in mixed-matrix membranes. This tutorial review may serve as first introduction into the topic. Further references are linked for the interested reader.
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13
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Bilo M, Münzner M, Küster C, Enke D, Lee YJ, Fröba M. Structural Changes of Hierarchically Nanoporous Organosilica/Silica Hybrid Materials by Pseudomorphic Transformation. Chemistry 2020; 26:11220-11230. [PMID: 32196769 PMCID: PMC7497150 DOI: 10.1002/chem.202000512] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Indexed: 11/11/2022]
Abstract
Herein, it is reported how pseudomorphic transformation of divinylbenzene (DVB)-bridged organosilica@controlled pore glasses (CPG) offers the possibility to generate hierarchically porous organosilica/silica hybrid materials. CPG is utilized to provide granular shape/size and macroporosity and the macropores of the CPG is impregnated with organosilica phase, forming hybrid system. By subsequent pseudomorphic transformation, an ordered mesopore phase is generated while maintaining the granular shape and macroporosity of the CPG. Surface areas and mesopore sizes in the hierarchical structure are tunable by the choice of the surfactant and transformation time. Two-dimensional magic angle spinning (MAS) NMR spectroscopy demonstrated that micellar-templating affects both organosilica and silica phases and pseudomorphic transformation induces phase transition. A double-layer structure of separate organosilica and silica layers is established for the impregnated material, while a single monophase consisting of randomly distributed T and Q silicon species at the molecular level is identified for the pseudomorphic transformed materials.
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Affiliation(s)
- Malina Bilo
- Institute of Inorganic and Applied Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146, Hamburg, Germany
| | - Maximilian Münzner
- Institute of Chemical Technology, University of Leipzig, Linnéstraße 3, 04103, Leipzig, Germany
| | - Christian Küster
- Institute of Chemical Technology, University of Leipzig, Linnéstraße 3, 04103, Leipzig, Germany
| | - Dirk Enke
- Institute of Chemical Technology, University of Leipzig, Linnéstraße 3, 04103, Leipzig, Germany
| | - Young Joo Lee
- Institute of Inorganic and Applied Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146, Hamburg, Germany
| | - Michael Fröba
- Institute of Inorganic and Applied Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146, Hamburg, Germany
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14
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Cabaud C, Barré Y, De Windt L, Grandjean A. Linking the multiscale porous structure of hexacyanoferrate-loaded silica monoliths to their hydrodynamic and cesium sorption properties. Sep Purif Technol 2019. [DOI: 10.1016/j.seppur.2019.115796] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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15
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Haas CP, Tallarek U. Kinetics Studies on a Multicomponent Knoevenagel-Michael Domino Reaction by an Automated Flow Reactor. ChemistryOpen 2019; 8:606-614. [PMID: 31110932 PMCID: PMC6511915 DOI: 10.1002/open.201900124] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Indexed: 12/13/2022] Open
Abstract
The optimization of complex chemical reaction systems is often a troublesome and time‐consuming process. The application of modern technologies, including automated reactors and analytics, opens the avenue for generating large data sets on chemical reaction processes in a short period of time. In this work, an automated flow reactor is used to present detailed kinetics and mechanistic studies about an amine‐catalyzed Knoevenagel−Michael domino reaction to yield tetrahydrochromene derivatives. High‐performance monoliths as catalyst supports and online coupled HPLC analysis allow for time‐efficient data generation. We show that the two‐step multicomponent domino reaction does not follow the kinetics of consecutive reaction steps proceeding independently from each other. Instead, the starting materials of both individual reactions compete for the active sites on the heterogeneous catalyst, which lowers the rate constants of both steps. This knowledge was used to implement a more efficient experimental setup which increased the turnover numbers of the catalyst, without adjusting common reaction parameters like temperature, reaction time, and concentrations.
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Affiliation(s)
- Christian P Haas
- Department of Chemistry Philipps-Universität Marburg Hans-Meerwein-Strasse 4 D-35032 Marburg Germany
| | - Ulrich Tallarek
- Department of Chemistry Philipps-Universität Marburg Hans-Meerwein-Strasse 4 D-35032 Marburg Germany
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16
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Cabaud C, Barré Y, De Windt L, Gill S, Dooryhée E, Moloney MP, Massoni N, Grandjean A. Removing Cs within a continuous flow set-up by an ionic exchanger material transformable into a final waste form. ADSORPTION 2019. [DOI: 10.1007/s10450-019-00040-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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17
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Abstract
The high performance of chemically-modified silica gel packing materials is based on the utilization of pure silica gels. Earlier silica gels used to be made from inorganic silica; however, nowadays, silica gels are made from organic silanes. The surface smoothness and lack of trace metals of new silica gels permits easy surface modifications (chemical reactions) and improves the reproducibility and stability. Sharpening peak symmetry is based on developing better surface modification methods (silylation). Typical examples can be found in the chromatography of amitriptyline for silanol testing and that of quinizarin for trace metal testing. These test compounds were selected and demonstrated sensitive results in the measurement of trace amounts of either silanol or trace metals. Here, we demonstrate the three-dimensional model chemical structures of bonded-phase silica gels with surface electron density for easy understanding of the molecular interaction sites with analytes. Furthermore, a quantitative explanation of hydrophilic and hydrophobic liquid chromatographies was provided. The synthesis methods of superficially porous silica gels and their modified products were introduced.
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18
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Hossain KMZ, Patel U, Kennedy AR, Macri-Pellizzeri L, Sottile V, Grant DM, Scammell BE, Ahmed I. Porous calcium phosphate glass microspheres for orthobiologic applications. Acta Biomater 2018; 72:396-406. [PMID: 29604438 DOI: 10.1016/j.actbio.2018.03.040] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 03/07/2018] [Accepted: 03/22/2018] [Indexed: 01/07/2023]
Abstract
Orthobiologics is a rapidly advancing field utilising cell-based therapies and biomaterials to enable the body to repair and regenerate musculoskeletal tissues. This paper reports on a cost-effective flame spheroidisation process for production of novel porous glass microspheres from calcium phosphate-based glasses to encapsulate and deliver stem cells. Careful selection of the glass and pore-forming agent, along with a manufacturing method with the required processing window enabled the production of porous glass microspheres via a single-stage manufacturing process. The morphological and physical characterisation revealed porous microspheres with tailored surface and interconnected porosity (up to 76 ± 5%) with average pore size of 55 ± 8 µm and surface areas ranging from 0.34 to 0.9 m2 g-1. Furthermore, simple alteration of the processing parameters produced microspheres with alternate unique morphologies, such as with solid cores and surface porosity only. The tuneable porosity enabled control over their surface area, degradation profiles and hence ion release rates. Furthermore, cytocompatibility of the microspheres was assessed using human mesenchymal stem cells via direct cell culture experiments and analysis confirmed that they had migrated to within the centre of the microspheres. The novel microspheres developed have huge potential for tissue engineering and regenerative medicine applications. STATEMENT OF SIGNIFICANCE This manuscript highlights a simple cost-effective one-step process for manufacturing porous calcium phosphate-based glass microspheres with varying control over surface pores and fully interconnected porosity via a flame spheroidisation process. Moreover, a simple alteration of the processing parameters can produce microspheres which have a solid core with surface pores only. The tuneable porosity enabled control over their surface area, degradation profiles and hence ion release rates. The paper also shows that stem cells not only attach and proliferate but more importantly migrate to within the core of the porous microspheres, highlighting applications for bone tissue engineering and regenerative medicine.
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19
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Miura H, Bon V, Senkovska I, Ehrling S, Watanabe S, Ohba M, Kaskel S. Tuning the gate-opening pressure and particle size distribution of the switchable metal-organic framework DUT-8(Ni) by controlled nucleation in a micromixer. Dalton Trans 2018; 46:14002-14011. [PMID: 28976513 DOI: 10.1039/c7dt02809a] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Controlled nucleation in a micromixer and further crystal growth were used to synthesize Ni2(2,6-ndc)2dabco (2,6-ndc - 2,6-naphthalenedicarboxylate, dabco - 1,4-diazabicyclo[2.2.2]octane), also termed DUT-8(Ni) (DUT = Dresden University of Technology), with narrow particle size distribution in a range of a few nm to several μm. The crystal size was found to significantly affect the switching characteristics, in particular the gate opening pressure in nitrogen adsorption isotherms at 77 K for this highly porous and flexible network. Below a critical size of about 500 nm, a type Ia isotherm typical of rigid MOFs is observed, while above approximately 1000 nm a pronounced gating behaviour is detected, starting at p/p0 = 0.2. With increasing crystal size this transition gate becomes steeper indicating a more uniform distribution of activation energies within the crystal ensemble. At an intermediate size (500-1000 nm), the DUT-8(Ni) crystals close during activation but cannot be reopened by nitrogen at 77 K possibly indicating monodomain switching.
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Affiliation(s)
- Hiroki Miura
- Department of Inorganic Chemistry, Technische Universität Dresden, Bergstrasse 66, D-01062 Dresden, Germany.
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20
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Reich SJ, Svidrytski A, Hlushkou D, Stoeckel D, Kübel C, Höltzel A, Tallarek U. Hindrance Factor Expression for Diffusion in Random Mesoporous Adsorbents Obtained from Pore-Scale Simulations in Physical Reconstructions. Ind Eng Chem Res 2018. [DOI: 10.1021/acs.iecr.7b04840] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Stefan-Johannes Reich
- Department
of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Strasse 4, 35032 Marburg, Germany
| | - Artur Svidrytski
- Department
of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Strasse 4, 35032 Marburg, Germany
| | - Dzmitry Hlushkou
- Department
of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Strasse 4, 35032 Marburg, Germany
| | - Daniela Stoeckel
- Department
of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Strasse 4, 35032 Marburg, Germany
- Institute of Physical Chemistry, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 58, 35392 Gießen, Germany
| | - Christian Kübel
- Institute
of Nanotechnology and Karlsruhe Nano Micro Facility, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Alexandra Höltzel
- Department
of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Strasse 4, 35032 Marburg, Germany
| | - Ulrich Tallarek
- Department
of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Strasse 4, 35032 Marburg, Germany
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21
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Sun XJ, Zhang X, Dong H, Yang DD, Tang HL, Zhai YC, Wei JZ, Zhang FM. Porous metal–organic gel assisted by l-tartaric acid ligand for efficient and controllable drug delivery. NEW J CHEM 2018. [DOI: 10.1039/c8nj02007h] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The synthetic route for drug carriers based on porous Al-MOG.
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Affiliation(s)
- Xiao-Jun Sun
- Key Laboratory of Green Chemical Engineering and Technology of College of Heilongjiang Province
- College of Chemical and Environmental Engineering
- Harbin University of Science and Technology
- Harbin 150040
- P. R. China
| | - Xin Zhang
- Key Laboratory of Green Chemical Engineering and Technology of College of Heilongjiang Province
- College of Chemical and Environmental Engineering
- Harbin University of Science and Technology
- Harbin 150040
- P. R. China
| | - Hong Dong
- Key Laboratory of Green Chemical Engineering and Technology of College of Heilongjiang Province
- College of Chemical and Environmental Engineering
- Harbin University of Science and Technology
- Harbin 150040
- P. R. China
| | - Dou-Dou Yang
- Key Laboratory of Green Chemical Engineering and Technology of College of Heilongjiang Province
- College of Chemical and Environmental Engineering
- Harbin University of Science and Technology
- Harbin 150040
- P. R. China
| | - Hong-Liang Tang
- Key Laboratory of Green Chemical Engineering and Technology of College of Heilongjiang Province
- College of Chemical and Environmental Engineering
- Harbin University of Science and Technology
- Harbin 150040
- P. R. China
| | - Ya-Chao Zhai
- Key Laboratory of Green Chemical Engineering and Technology of College of Heilongjiang Province
- College of Chemical and Environmental Engineering
- Harbin University of Science and Technology
- Harbin 150040
- P. R. China
| | - Jin-Zhi Wei
- Key Laboratory of Green Chemical Engineering and Technology of College of Heilongjiang Province
- College of Chemical and Environmental Engineering
- Harbin University of Science and Technology
- Harbin 150040
- P. R. China
| | - Feng-Ming Zhang
- Key Laboratory of Green Chemical Engineering and Technology of College of Heilongjiang Province
- College of Chemical and Environmental Engineering
- Harbin University of Science and Technology
- Harbin 150040
- P. R. China
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22
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Chatterjee S, Potdar A, Kuhn S, Kumaraswamy G. Preparation of macroporous scaffolds with holes in pore walls and pressure driven flows through them. RSC Adv 2018; 8:24731-24739. [PMID: 35542148 PMCID: PMC9082364 DOI: 10.1039/c8ra03867h] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2018] [Accepted: 07/02/2018] [Indexed: 11/21/2022] Open
Abstract
Controlling the pore architecture in macroporous scaffolds has important implications for their use as reactor packings and as catalyst supports.
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Affiliation(s)
- Soumyajyoti Chatterjee
- J-101
- Polymers and Advanced Materials Laboratory
- Complex Fluids and Polymer Engineering
- Polymer Science and Engineering Division
- CSIR-National Chemical Laboratory
| | - Aditi Potdar
- KU Leuven
- Department of Chemical Engineering
- Leuven 3001
- Belgium
| | - Simon Kuhn
- KU Leuven
- Department of Chemical Engineering
- Leuven 3001
- Belgium
| | - Guruswamy Kumaraswamy
- J-101
- Polymers and Advanced Materials Laboratory
- Complex Fluids and Polymer Engineering
- Polymer Science and Engineering Division
- CSIR-National Chemical Laboratory
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23
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Kohns R, Haas CP, Höltzel A, Splith C, Enke D, Tallarek U. Hierarchical silica monoliths with submicron macropores as continuous-flow microreactors for reaction kinetic and mechanistic studies in heterogeneous catalysis. REACT CHEM ENG 2018. [DOI: 10.1039/c8re00037a] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The proposed scheme enables academic laboratories to prepare hierarchical silica monoliths as continuous-flow microreactors for kinetic studies in heterogeneous catalysis.
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Affiliation(s)
- Richard Kohns
- Department of Chemistry
- Philipps-Universität Marburg
- 35032 Marburg
- Germany
- Institute of Chemical Technology
| | - Christian P. Haas
- Department of Chemistry
- Philipps-Universität Marburg
- 35032 Marburg
- Germany
| | - Alexandra Höltzel
- Department of Chemistry
- Philipps-Universität Marburg
- 35032 Marburg
- Germany
| | - Christian Splith
- Institute of Chemical Technology
- Universität Leipzig
- 04103 Leipzig
- Germany
| | - Dirk Enke
- Institute of Chemical Technology
- Universität Leipzig
- 04103 Leipzig
- Germany
| | - Ulrich Tallarek
- Department of Chemistry
- Philipps-Universität Marburg
- 35032 Marburg
- Germany
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24
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Matsuyama K, Tanaka S, Kato T, Okuyama T, Muto H, Miyamoto R, Bai HZ. Supercritical fluid-assisted immobilization of Pd nanoparticles in the mesopores of hierarchical porous SiO2 for catalytic applications. J Supercrit Fluids 2017. [DOI: 10.1016/j.supflu.2017.07.032] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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25
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Reising AE, Schlabach S, Baranau V, Stoeckel D, Tallarek U. Analysis of packing microstructure and wall effects in a narrow-bore ultrahigh pressure liquid chromatography column using focused ion-beam scanning electron microscopy. J Chromatogr A 2017; 1513:172-182. [DOI: 10.1016/j.chroma.2017.07.049] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Revised: 07/03/2017] [Accepted: 07/13/2017] [Indexed: 10/19/2022]
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26
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Uhlig H, Hollenbach J, Rogaczewski M, Matysik J, Brieler FJ, Fröba M, Enke D. Pseudomorphic Transformation of Porous Glasses into Micelle-Templated Silica. CHEM-ING-TECH 2017. [DOI: 10.1002/cite.201600189] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Hans Uhlig
- University of Leipzig; Institut für Nichtklassische Chemie e.V.; Permoserstraße 15 04318 Leipzig Germany
| | - Julia Hollenbach
- University of Leipzig; Institute of Analytical Chemistry; Linnéstraße 3 04103 Leipzig Germany
| | - Matthias Rogaczewski
- University of Hamburg; Institute of Inorganic and Applied Chemistry; Martin-Luther-King-Platz 6 20146 Hamburg Germany
| | - Jörg Matysik
- University of Leipzig; Institute of Analytical Chemistry; Linnéstraße 3 04103 Leipzig Germany
| | - Felix J. Brieler
- University of Hamburg; Institute of Inorganic and Applied Chemistry; Martin-Luther-King-Platz 6 20146 Hamburg Germany
| | - Michael Fröba
- University of Hamburg; Institute of Inorganic and Applied Chemistry; Martin-Luther-King-Platz 6 20146 Hamburg Germany
| | - Dirk Enke
- University of Leipzig; Institute of Chemical Technology; Linnéstraße 3 04103 Leipzig Germany
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27
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Müllner T, Zankel A, Höltzel A, Svec F, Tallarek U. Morphological Properties of Methacrylate-Based Polymer Monoliths: From Gel Porosity to Macroscopic Inhomogeneities. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:2205-2214. [PMID: 28186759 DOI: 10.1021/acs.langmuir.7b00337] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Shaping chemical interfaces of hard and soft matter materials into physical morphologies that guarantee excellent transport properties is of central importance for technologies relying on adsorption, separation, and reaction at the interface. Polymer monoliths with a hierarchically structured pore space, for example, are widely used in flow-driven processes, whose efficiency depends on the morphology of the support material over several length scales. Compared with alternative support structures, particularly silica monoliths, polymer monoliths yield lower efficiency, which suggests a suboptimal morphology. Based on physical reconstruction by serial block-face scanning electron microscopy we evaluate the structural features of a methacrylate-based polymer monolith from the pore scale to the column scale. The morphological data reveal a homogeneous polymer skeleton with a solute-impenetrable core-porous shell architecture and a heterogeneous macropore space that suffers from inhomogeneities at the short-range and the transcolumn scale. Although the morphology of the polymer phase is favorable to efficient mass transport, the performance of the polymer monolith is limited by severe transcolumn gradients in macroporosity and macropore size. We propose to overcome these morphological limitations by pursuing a preparation strategy that involves active rather than passive shaping of the macropore space, for example, by using silica monoliths as templating structures for polymer monolith preparation.
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Affiliation(s)
- Tibor Müllner
- Department of Chemistry, Philipps-Universität Marburg , Hans-Meerwein-Strasse 4, 35032 Marburg, Germany
| | - Armin Zankel
- Institute of Electron Microscopy and Nanoanalysis, Graz University of Technology, and Graz Centre for Electron Microscopy, Steyrergasse 17, 8010 Graz, Austria
| | - Alexandra Höltzel
- Department of Chemistry, Philipps-Universität Marburg , Hans-Meerwein-Strasse 4, 35032 Marburg, Germany
| | - Frantisek Svec
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology , 100029 Beijing, China
| | - Ulrich Tallarek
- Department of Chemistry, Philipps-Universität Marburg , Hans-Meerwein-Strasse 4, 35032 Marburg, Germany
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28
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Meinusch R, Ellinghaus R, Hormann K, Tallarek U, Smarsly BM. On the underestimated impact of the gelation temperature on macro- and mesoporosity in monolithic silica. Phys Chem Chem Phys 2017; 19:14821-14834. [DOI: 10.1039/c7cp01846k] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Elucidating pore formation in monolithic SiO2: small variations in gelation temperature have a surprisingly strong impact on the meso- and macroporosity.
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Affiliation(s)
- Rafael Meinusch
- Institute of Physical Chemistry
- Justus-Liebig-Universität Giessen
- 35392 Giessen
- Germany
- Center for Materials Research (LaMa)
| | - Rüdiger Ellinghaus
- Institute of Physical Chemistry
- Justus-Liebig-Universität Giessen
- 35392 Giessen
- Germany
- Center for Materials Research (LaMa)
| | - Kristof Hormann
- Department of Chemistry
- Philipps-Universität Marburg
- 35032 Marburg
- Germany
- Thermo Fisher Scientific
| | - Ulrich Tallarek
- Department of Chemistry
- Philipps-Universität Marburg
- 35032 Marburg
- Germany
| | - Bernd M. Smarsly
- Institute of Physical Chemistry
- Justus-Liebig-Universität Giessen
- 35392 Giessen
- Germany
- Center for Materials Research (LaMa)
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29
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Haas CP, Müllner T, Kohns R, Enke D, Tallarek U. High-performance monoliths in heterogeneous catalysis with single-phase liquid flow. REACT CHEM ENG 2017. [DOI: 10.1039/c7re00042a] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
On-line control and monitoring in heterogeneous catalysis utilizing high-performance supports allows rapid screening of intrinsic reaction parameters in continuous-flow mode.
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Affiliation(s)
- Christian P. Haas
- Department of Chemistry
- Philipps-Universität Marburg
- 35032 Marburg
- Germany
| | - Tibor Müllner
- Department of Chemistry
- Philipps-Universität Marburg
- 35032 Marburg
- Germany
| | - Richard Kohns
- Department of Chemistry
- Philipps-Universität Marburg
- 35032 Marburg
- Germany
- Institute of Chemical Technology
| | - Dirk Enke
- Institute of Chemical Technology
- Universität Leipzig
- 04103 Leipzig
- Germany
| | - Ulrich Tallarek
- Department of Chemistry
- Philipps-Universität Marburg
- 35032 Marburg
- Germany
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