Using High-Power UV-LED to Accelerate a Decatungstate-Anion-Catalyzed Reaction: A Model Study for the Quick Oxidation of Benzyl Alcohol to Benzoic Acid Using Molecular Oxygen

Hyodo, Mamoru; Iwano, Hitomi; Kasakado, Takayoshi; Fukuyama, Takahide; Ryu, Ilhyong

doi:10.3390/mi12111307

Cited by 12 publications

(13 citation statements)

References 38 publications

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“…Finally, to accelerate the photocatalytic oxidative cleavage reaction, we examined a flow oxidation reaction using a photo flow reactor and a high-power UV LED (365 nm, 240 W), because we learned in our recent work that the oxidation of benzyl alcohol to benzoic acid could be effectively accelerated under flow conditions. , As illustrated in Scheme , an aqueous acetonitrile solution containing 1a (50 mM) and the decatungstate catalyst (2 mol %) was mixed with molecular oxygen using a T-shaped mixer and the gas/liquid mixture was then introduced into a PFA tubing reactor. We found that a high-speed oxidation occurred with acetophenone ( 2a ) being produced in 89% GC yield in a much shorter reaction (residence) time of 6 min compared with the batch protocol.…”

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confidence: 99%

Photocatalytic Oxidative Cleavage of Alkenes by Molecular Oxygen: Reaction Scope, Mechanistic Insights, and Flow Application

Shih

Hyodo

et al. 2022

J. Org. Chem.

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The oxidative cleavage of C�C bonds with molecular oxygen was promoted effectively by a catalytic amount of a decatungstate photocatalyst using black light irradiation (365 nm). Not only aromatic ketones but also aliphatic ketones were obtained by the photocatalytic protocol. The continuous flow reaction of α-methylstyrene using a highpower ultraviolet light-emitting diode (365 nm) dramatically decreased the reaction time.

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confidence: 99%

Photocatalytic Oxidative Cleavage of Alkenes by Molecular Oxygen: Reaction Scope, Mechanistic Insights, and Flow Application

Shih

Hyodo

et al. 2022

J. Org. Chem.

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“…Yields were determined by using the percentage peak area method with compensation for the relative sensitivities of each component. Product 2 and byproduct 2' were confirmed by 1 H and 13 C NMR analysis (see Supporting Information File 1).…”

Section: Methodsmentioning

confidence: 89%

“…We thought that if rationally designed scalable photoflow setups were available, flow C-H chlorination reactions using chlorine gas would be able to focus on production. In this study, we tested a novel photoflow setup consisting of quartz-made straight-line reactors, which are provided from MiChS (LX-1, Figure 1a) and a high-power LED (MiChS LED-s, 365 ± 5 nm, Figure 1b) [13]. Each channel track has a 2 mm depth and 557 mm length, while the width varies from 6 or 13 mm depending on the number of channels 7 or 5, respectively.…”

Section: Introductionmentioning

confidence: 99%

High-speed C–H chlorination of ethylene carbonate using a new photoflow setup

Kasakado¹,

Fukuyama²,

Nakagawa³

et al. 2022

Beilstein J. Org. Chem.

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We report the high-speed C–H chlorination of ethylene carbonate, which gives chloroethylene carbonate, a precursor to vinylene carbonate. A novel photoflow setup designed for a gas–liquid biphasic reaction turned out to be useful for the direct use of chlorine gas. The setup employed sloped channels so as to make the liquid phase thinner, ensuring a high surface-to-volume ratio. When ethylene carbonate was introduced to the reactor, the residence time was measured to be 15 or 30 s, depending on the slope of the reactor set at 15 or 5°, respectively. Such short time of exposition sufficed the photo C–H chlorination. The partial irradiation of the flow channels also sufficed for the C–H chlorination, which is consistent with the requirement of photoirradiation for the purpose of radical initiation. Near-complete selectivity for single chlorination required the low conversion of ethylene carbonate such as 9%, which was controlled by limited introduction of chlorine gas. At a higher conversion of ethylene carbonate such as 61%, the selectivity for monochlorinated ethylene carbonate over dichlorinated ethylene carbonate was 86%. We found that the substrate contamination with water negatively influenced the performance of the C–H chlorination.

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“…Photocatalytic aerobic oxidation of benzyl alcohol has emerged as a green methodology for the synthesis of useful industrial chemical intermediates (e.g., benzaldehyde, benzoic acid). , To evaluate the photocatalytic activities of compounds 1 – 3 , the photocatalytic aerobic oxidation of benzyl alcohol was selected as a model reaction, which was carried out at room temperature under 10 W 365 nm light irradiation. Before the reaction, the influencing factors such as the solvent and the amount of catalyst were screened using compound 1 as a heterogeneous photocatalyst (Table ).…”

Section: Results and Discussionmentioning

confidence: 99%

Three-Dimensional Silver-Containing Polyoxotungstate Frameworks for Photocatalytic Aerobic Oxidation of Benzyl Alcohol

Zhang

Wang

et al. 2022

Inorg. Chem.

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Photocatalytic organic transformation derived by functionalized polyoxometalate (POM)-based metal−organic frameworks provides a feasible route for fine chemical synthesis. Herein, three kinds of photoactive threedimensional silver-containing polyoxotungstate frameworks are synthesized with the formulasIn compounds 1−3, the cationic Ag−triazole clusters with diverse nuclei serve as nodes to assemble with rigid bridging ligands (L) and polyoxoanions to extend into stable three-dimensional frameworks, in which Keggin-type anions act as guests or pendants. When using them as heterogeneous photocatalysts, compounds 1−3 show high catalytic activity and selectivity for the photocatalytic aerobic oxidation of benzyl alcohol to benzoic acid under 10 W 365 nm light irradiation. Among them, compound 1 exhibits the highest performance with ca. 99% benzyl alcohol conversion and 99% selectivity of benzoic acid in 9 h. Compounds 2 and 3 show ca. 79 and 88% conversions of benzyl alcohol, respectively, which are higher than those of the individual Keggin-type precursors. Moreover, mechanism investigation suggests that the synergistic cooperation occurring between cationic Ag−triazole clusters and Keggin-type polyoxoanions modulates the energy band structures of compounds 1−3, resulting in the efficient separation of photogenerated carriers and accelerating the aerobic oxidation of benzyl alcohol. This work provides some important guidance for the design and development of efficient POM-based photocatalysts for practical organic transformation.

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Using High-Power UV-LED to Accelerate a Decatungstate-Anion-Catalyzed Reaction: A Model Study for the Quick Oxidation of Benzyl Alcohol to Benzoic Acid Using Molecular Oxygen

Cited by 12 publications

References 38 publications

Photocatalytic Oxidative Cleavage of Alkenes by Molecular Oxygen: Reaction Scope, Mechanistic Insights, and Flow Application

Photocatalytic Oxidative Cleavage of Alkenes by Molecular Oxygen: Reaction Scope, Mechanistic Insights, and Flow Application

High-speed C–H chlorination of ethylene carbonate using a new photoflow setup

Three-Dimensional Silver-Containing Polyoxotungstate Frameworks for Photocatalytic Aerobic Oxidation of Benzyl Alcohol

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