A novel and active catalyst Ag/ZnO for oxidant-free dehydrogenation of alcohols

Hosseini‐Sarvari, Mona; Ataee-Kachouei, Tahereh; Moeini, Fatemeh

doi:10.1016/j.materresbull.2015.07.019

Cited by 31 publications

(18 citation statements)

References 63 publications

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“…The second category covers those cases where large catalytic particles ( R ≫r AD ) are supported on catalytic surfaces. Hosseini‐Sarvari and co‐workers prepared Ag/ZnO catalysts for the oxidant‐free dehydrogenation of alcohols (Figure ) . While this material catalyses the same reaction reported by Shimizu et al., the particles here are much larger (40–50 nm).…”

Section: Case Studiesmentioning

confidence: 51%

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Cooperative Surface‐Particle Catalysis: The Role of the “Active Doughnut” in Catalytic Oxidation

2018

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We consider the factors that govern the activity of bifunctional catalysts comprised of active particles supported on active surfaces. Such catalysts are interesting because the adsorption and diffusion steps, which are often discounted in “conventional” catalytic scenarios, play a key role here. We present an intuitive model, the so‐called “active doughnut” concept, defining an active catalytic region around the supported particles. This simple model explains the role of adsorption and diffusion steps in cascade catalytic cycles for active particles supported on active surfaces. The concept has two important practical implications. First, the reaction rate is no longer proportional to the number of active sites, but rather to the number of “communicative” active sites—those available to the reaction intermediates during their respective lifetimes. Second, it generates an important testable prediction concerning the dependence of the total reaction rate on the particle size. With these tools at hand, we examine six experimental examples of catalytic oxidation from the literature, and show that the active doughnut concept gives valuable insight even when detailed mechanistic information is hard to come by.

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Section: Case Studiesmentioning

confidence: 51%

“… a) Oxidation of benzyl alcohol, catalysed in Hosseini‐Sarvari's study by Ag/ZnO. Reaction conditions: 1 mmol benzyl alcohol, 2 mL toluene, 1 mmol KOH, 5 mg catalyst, 100 °C, 8 h. b) TEM image of Ag/ZnO . c) The “active doughnut step”: recombination of particle‐bound hydride with a proton diffusing from the surface.…”

Section: Case Studiesmentioning

confidence: 99%

Cooperative Surface‐Particle Catalysis: The Role of the “Active Doughnut” in Catalytic Oxidation

2018

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“…For instance, Golafzani et al [98] reported liquid phase selective oxidation of benzyl alcohol using TCPP/Zn-Fe 2 O 4 @ZnO catalyst via aqueous hydrogen peroxide as a green oxidant in CH 3 CN as solvent with benzyl alcohol conversion of 96%, excellent selectivity about 100%, and the specific activity of this conversion was about 32 mmol·g −1 ·h −1 within 1.5 h under reflux conditions. Another example, Sarvari et al [99] have prepared Nano Ag/ZnO catalyst and used for oxidant-free oxidation of benzyl alcohol to benzaldehyde. The nano Ag/ZnO catalyst exhibited 98% benzyl alcohol conversion and more than 99% benzaldehyde selectivity along with 24.5 mmol·g −1 ·h −1 specific activity after long reaction time 8 h at 100 • C. On the basis of these findings, it can be said that ZnO x (1%)-MnCO 3 /(1%)HRG nanocomposite has found to be the best choice for the alcohol oxidation.…”

Section: Influence Of Catalyst Amountmentioning

confidence: 99%

Mixed Zinc/Manganese on Highly Reduced Graphene Oxide: A Highly Active Nanocomposite Catalyst for Aerial Oxidation of Benzylic Alcohols

et al. 2017

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Nanocomposites of highly reduced graphene oxide (HRG) and ZnO x nanoparticles doped manganese carbonate containing different percentages of HRG were prepared via a facile co-precipitation method.The prepared sample calcined at 300 • C yielded i.e., ZnO x (1%)-MnCO 3 /(X%)HRG (where X = 0-7), calcination at 400 • C and 500 • C, yielded different manganese oxides i.e., ZnO x (1%)-MnO 2 /(X%)HRG and ZnO x (1%)-Mn 2 O 3 /(X%)HRG respectively. The prepared catalyst were subjected to catalytic evaluation and a comparative catalytic study between carbonates and oxides for the liquid-phase aerobic oxidation of benzylic alcohols to corresponding aldehydes using molecular oxygen as an eco-friendly oxidant without adding additives or bases. The influence of various parameters such as percentage of HRG, reaction time, catalyst amount, calcination and reaction temperature was systematically examined to optimize reaction conditions using oxidation of benzyl alcohol as a substrate model. It was found that the catalytic performance is remarkably enhanced after using HRG as catalyst co-dopant for the aerobic oxidation of alcohols, possibly owing to the presence of carbon defects and oxygenated functional groups on HRG surface. The as-synthesized catalysts were characterized by SEM, EDX, XRD, Raman, TGA, BET, and FT-IR. Under optimal conditions, the catalyst with composition ZnO x (1%)-MnCO 3 /(1%)HRG calcined at 300 • C exhibited remarkable specific activity (57.1 mmol·g −1 ·h −1 ) with 100% conversion of benzyl alcohol and more than 99% product selectivity within extremely short time (7 min). The as-prepared catalyst was re-used up to five consecutive times without significant decrease in its activity and selectivity. To the best of our knowledge, the achieved specific activity is the highest so far compared to the earlier reported catalysts used for the benzyl alcohol oxidation. A wide range of substituted benzylic and aliphatic alcohols were selectively oxidized into their corresponding aldehydes with complete convertibility and selectivity in short reaction times without over-oxidation to the acids. Due to their significant low cost, superior reproducibility, excellent catalytic efficiency, the ZnO x (1%)-MnCO 3 /(X%)HRG nanocomposites possess several application prospect in other organic chemistry reactions.

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“…In contrast, all listed catalysts take a very long reaction time to completely oxidize 1-phenylethanol and require higher reaction temperature. For instance, Hosseini-Sarvari et al [76] have prepared Ag nanoparticles doped ZnO support (Ag/ZnO) and used it as a catalyst for selective oxidation of alcohols to their corresponding carbonyls. The nano Ag/ZnO catalyst provided 90% conversion of 1-phenylethanol and more than 99% selectivity of acetophenone along with 30 mmol⋅g −1 ⋅h −1 specific activity after long reaction time of 6 h at 100 ∘ C. In another example, Nepak and Darbha [70] reported liquid-phase selective alcohol oxidation over Au-Pd NPs doped in sodium titanate nanotubes (NaTNTs) as a catalyst.…”

Section: Influence Of Catalystmentioning

confidence: 99%

Synthesis, Characterization, and Relative Study on the Catalytic Activity of Zinc Oxide Nanoparticles Doped MnCO₃, –MnO₂, and –Mn₂O₃ Nanocomposites for Aerial Oxidation of Alcohols

Assal

Kuniyil

Shaik

et al. 2017

Journal of Chemistry

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Zinc oxide nanoparticles doped manganese carbonate catalysts [ % ZnO x -MnCO 3 ] (where = 0-7) were prepared via a facile and straightforward coprecipitation procedure, which upon different calcination treatments yields different manganese oxides, that is, [ % ZnO x -MnO 2 ] and [ % ZnO x -Mn 2 O 3 ]. A comparative catalytic study was conducted to evaluate the catalytic efficiency between carbonates and oxides for the selective oxidation of secondary alcohols to corresponding ketones using molecular oxygen as a green oxidizing agent without using any additives or bases. The prepared catalysts were characterized by different techniques such as SEM, EDX, XRD, TEM, TGA, BET, and FTIR spectroscopy. The 1% ZnO x -MnCO 3 calcined at 300 ∘ C exhibited the best catalytic performance and possessed highest surface area, suggesting that the calcination temperature and surface area play a significant role in the alcohol oxidation. The 1% ZnO x -MnCO 3 catalyst exhibited superior catalytic performance and selectivity in the aerial oxidation of 1-phenylethanol, where 100% alcohol conversion and more than 99% product selectivity were obtained in only 5 min with superior specific activity (48 mmol⋅g −1 ⋅h −1 ) and 390.6 turnover frequency (TOF). The specific activity obtained is the highest so far (to the best of our knowledge) compared to the catalysts already reported in the literatures used for the oxidation of 1-phenylethanol. It was found that ZnO x nanoparticles play an essential role in enhancing the catalytic efficiency for the selective oxidation of alcohols. The scope of the oxidation process is extended to different types of alcohols. A variety of primary, benzylic, aliphatic, allylic, and heteroaromatic alcohols were selectively oxidized into their corresponding carbonyls with 100% convertibility without overoxidation to the carboxylic acids under base-free conditions.

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A novel and active catalyst Ag/ZnO for oxidant-free dehydrogenation of alcohols

Cited by 31 publications

References 63 publications

Cooperative Surface‐Particle Catalysis: The Role of the “Active Doughnut” in Catalytic Oxidation

Cooperative Surface‐Particle Catalysis: The Role of the “Active Doughnut” in Catalytic Oxidation

Mixed Zinc/Manganese on Highly Reduced Graphene Oxide: A Highly Active Nanocomposite Catalyst for Aerial Oxidation of Benzylic Alcohols

Synthesis, Characterization, and Relative Study on the Catalytic Activity of Zinc Oxide Nanoparticles Doped MnCO₃, –MnO₂, and –Mn₂O₃ Nanocomposites for Aerial Oxidation of Alcohols

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A novel and active catalyst Ag/ZnO for oxidant-free dehydrogenation of alcohols

Cited by 31 publications

References 63 publications

Cooperative Surface‐Particle Catalysis: The Role of the “Active Doughnut” in Catalytic Oxidation

Cooperative Surface‐Particle Catalysis: The Role of the “Active Doughnut” in Catalytic Oxidation

Mixed Zinc/Manganese on Highly Reduced Graphene Oxide: A Highly Active Nanocomposite Catalyst for Aerial Oxidation of Benzylic Alcohols

Synthesis, Characterization, and Relative Study on the Catalytic Activity of Zinc Oxide Nanoparticles Doped MnCO3, –MnO2, and –Mn2O3 Nanocomposites for Aerial Oxidation of Alcohols

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Synthesis, Characterization, and Relative Study on the Catalytic Activity of Zinc Oxide Nanoparticles Doped MnCO₃, –MnO₂, and –Mn₂O₃ Nanocomposites for Aerial Oxidation of Alcohols