Tohoku University · Engineering
Professor Mizuho Yabushita's research lab specializes in the design and application of advanced porous materials—particularly metal-organic frameworks (MOFs) and functionalized carbons—for sustainable catalysis and molecular separation. The lab focuses on tailoring surface acidity and molecular recognition sites to enable selective transformations of biomass-derived molecules, such as glucose and sorbitol, into high-value chemicals like 5-hydroxymethylfurfural and 1,4-sorbitan. A key research direction involves understanding and controlling reaction mechanisms through precise site engineering and in-situ characterization techniques. The lab also explores selective adsorption phenomena based on weak interactions like CH-π and hydrogen bonding, enabling efficient separation of structurally similar sugars and furanic compounds.
Figures are computed from collected data and may differ slightly.
This manuscript demonstrates the synthesis of selective Lewis-acid sites in a metal–organic framework (MOF) for glucose transformation to 5-hydroxymethylfurfural (HMF). These sites are synthesized via partial phosphate modification of zirconia-cluster nodes in MOF NU-1000, which titrates strong Lewis-acid sites that would lead to undesired side reactions. Our mechanistic study using isotope tracer analysis and kinetic isotope effect measurements reveals that an isomerization–dehydration mechanis
Metal-organic framework (MOF) material NU-1000 adsorbs dimers cellobiose and lactose from aqueous solution, in amounts exceeding 1250 mg gNU-1000(-1) while completely excluding the adsorption of the monomer glucose, even in a competitive mode with cellobiose. The MOF also discriminates between dimers consisting of α and β linkages, showing no adsorption of maltose. Electronic structure calculations demonstrate that key to this selective molecular recognition is the number of favorable CH-π inter
Metal-organic framework NU-1000 selectively adsorbs furanics, while completely excluding the adsorption of monomeric sugars from the same aqueous mixture. The highly refined degree of molecular recognition exhibited by NU-1000 is exemplified with it selectively adsorbing 5-hydroxymethylfurfural, even in the presence of up to a 300-fold excess of glucose in solution.
Abstract 1,4-Sorbitan is a precursor to environmentally benign surfactants, which can be produced from biomass via sorbitol. Currently, sulfuric acid-catalyzed dehydration of sorbitol is the most widely used route for industrial synthesis of 1,4-sorbitan. In this work, we have studied the mechanism of the sorbitol dehydration by sulfuric acid. Our results show that both thermodynamic and kinetic parameters play significant roles to determine the yield of 1,4-sorbitan. Sorbitol preferentially for
This manuscript quantitatively investigates the effect of weak acid site surface density on adsorption and catalytic hydrolysis of long-chain β-glucans, with post-synthetically modified zeolite-templated carbon (ZTC) catalysts. Our approach requires ZTC-surface modification and overcomes previous limitations of pore collapse in accomplishing this, which has previously necessitated electrochemical methods. We demonstrate that mild ZTC treatment in hydrogen peroxide preserves the 1.1 nm micropores
The co-incorporation of Al and Fe at various relative ratios into the MFI-type zeolite framework enabled linear control of the density and strength of acid sites, and such well-tuned acidity led to a better catalyst lifetime.
Zeolites with an MFI-type framework topology containing both Al and Fe ([Al, Fe]-MFI) atoms were prepared via a two-step mechanochemically assisted method. In the first step, reactions between SiO2 and either α-Fe2O3 or γ-AlO(OH), induced by mechanical force during planetary ball-milling, produced one of the two types of amorphous composites. A second hydrothermal treatment of a mixture of these composites yielded the [Al, Fe]-MFI zeolites. The thus-prepared [Al, Fe]-MFI zeolites exhibited a lon
Abstract Carbon dioxide (CO 2 ) utilization as a carbonyl source is an attractive and promising approach to yielding value‐added organic urea derivatives, which are currently produced with toxic reagents such as phosgene and carbon monoxide, along with the contribution to mitigating global warming. However, the direct intermolecular reaction between CO 2 and amines into organic urea derivatives has thermodynamic limitations, and such obstacles need to be considered well in order to establish eff
Mordenite (MOR)-type zeolites with a Si/Al molar ratio of up to 13 with crystallite sizes of ca. 60 nm were successfully synthesized from Al-rich aluminosilicates with a Si/Al ratio of 2 and additional SiO<sub>2</sub> under seed-assisted hydrothermal conditions for 6 h or longer without any organic structure-directing agents (OSDAs). In stark contrast, under the same hydrothermal conditions for 6 h, control experiments using starting reagent(s), such as Al-poor aluminosilicate, pure SiO<sub>2</s
The paired Al species pre-formed in Al-rich amorphous aluminosilicates were transcribed into high-silica CHA-type zeolite frameworks under hydrothermal conditions, which offers a new approach to creating paired Al sites in zeolite frameworks. This Al-pair-rich CHA exhibited a higher Sr<sup>2+</sup> uptake than the control CHA zeolite synthesized by the conventional procedure.
The molecular origins of adsorption of lignin-derived phenolics to metal-organic framework NU-1000 are investigated from aqueous solution as well as in competitive mode with glucose present in the same aqueous mixture. A comparison of adsorption equilibrium constants (K<sub>ads</sub>) for phenolics functionalized with either carboxylic acid or aldehyde substituents demonstrated only a slight increase (less than a factor of 6) for the former according to both experiments and calculations. This sm
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