Selective hydrogenation of phenol and related derivatives

Zhong, Jiawei; Chen, Jinzhu; Chen, Limin

doi:10.1039/c4cy00583j

Cited by 117 publications

(76 citation statements)

References 136 publications

(230 reference statements)

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“…In agreement with ap reviousr eport, [9] the planar adsorption of phenol on the Ni surface favorsh ydrogenation. Therefore, this surfaces pecies (Figure 2a)u ndergoes hydrogenationt o yield 4 as the product.…”

supporting

confidence: 66%

“…From the current experimental evidence, one population of the adsorbed molecules appears to interact with the surface through the phenolic group and the aromatic ring (Figure a). In agreement with a previous report, the planar adsorption of phenol on the Ni surface favors hydrogenation. Therefore, this surface species (Figure a) undergoes hydrogenation to yield 4 as the product.…”

Section: Figurementioning

confidence: 98%

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On the Reactivity of Dihydro‐p‐coumaryl Alcohol towards Reductive Processes Catalyzed by Raney Nickel

et al. 2017

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There are severalestablished approaches for the reductive fractionation of lignocellulose (e.g.," catalytic upstream biorefining" and "lignin-first"approaches) that lead to alignin oil product that is composed primarily of dihydro-p-monolignols [e.g., 4-(3-hydroxypropyl)-2-methoxyphenol and 4-(3-hydroxypropyl)-2,6-dimethoxyphenol].A lthough effective catalytic methods have been developed to perform reductive or deoxygenative processeso nt he lignin oil, the influence of the 3-hydroxypropyls ubstituent on catalysta ctivity hasp reviously been overlooked. Herein, to better understand the reactivity of the depolymerized lignin oil obtained from catalytic upstream biorefiningp rocesses, dihydro-p-coumaryl alcohol was selected as am odel compound. Hydrogenation of this speciesi nt he presence of Raney Ni with molecular hydrogen led to ring saturation (100 %s electivity) in the absence of hydrodeoxygenation, whereas under hydrogen-transfer conditions with 2-propanol, hydrogenation occurred ( % 55 %s electivity) simultaneously with hydrodeoxygenation ( % 40 %s electivity). In ab roader context,t his study sheds light not only on the reactivity of dihydro-p-monolignols but also on the intricacies of the catalytic upstream biorefiningr eaction network in which these species are revealed to be key intermediates in the formation of lessfunctionalized p-alkylphenols.Undoubtedly,l ignin constitutest he primary renewable source of bulk and specialty aromatic chemicals.[1] Recently,s everal catalytic routes have been developed to convert lignocellulosic biomass into am ixture of compounds that show potential to replacep etroleum-basedr aw materials.[2] In this context,t he emerging field of "catalytic upstream biorefining" (CUB, sometimes referred to as "reductive fractionation" or the "ligninfirst" approach) has attracted increasinga ttention.[1a, 3] CUB encompasses processes for plant biomass deconstruction through the early-stage catalytic conversion of lignin (ECCL) by the action of ah ydrogenation catalyst.[1a] In our CUB process, on the basis of the ECCL by hydrogen-transfer( H-transfer) reactions catalyzed by Raney Ni, the lignin fractioni si solated as av iscous oil.[4] This lignin stream is rich in monophenolic species (< 65 %). Notably,t he type of functionalg roups on the propyls ide chain of the monophenolic compounds depends on both the selected catalysta nd the hydrogen source employed in the process. [4a, 5] Furthermore, the lignin oil also contains dimers and low-molecular-weight lignin oligomers (M w < 1000 Da) as minor products (> 35 %). Amid the monophenolic products obtained by H-transfer CUB in the presence of Raney Ni, two major products,d ihydro-p-sinapyl alcohol (1, Figure 1) and dihydro-p-coniferyl alcohol (2,F igure 1), are obtained from the biorefining of hardwoods. Understandably,t he CUB of (G-lignin-enriched) softwoods generates 2 as the major product.Products 1 and 2 incorporate three classes of oxygenated functional group, namely,the phenolic OH substituent, the methoxy group(s) ortho to the ph...

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supporting

confidence: 66%

Section: Figurementioning

confidence: 98%

On the Reactivity of Dihydro‐p‐coumaryl Alcohol towards Reductive Processes Catalyzed by Raney Nickel

et al. 2017

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“…These results show that Pd/CeO 2 is competitive with the best-performing catalysts reported for the liquid−solid interfacial hydrogenation of phenol. 4 Catalysts prepared in the same way using other commonly employed supports (e.g., alumina, silica, and carbon) gave significantly lower conversion under the same reaction conditions. This could be due to the weak interactions between the supports and Pd, which lead to low catalyst dispersion (Table S1 in the Supporting Information) or due to the inability to shuttle hydrogen from Pd to nonreducible supports (i.e., spillover), 51 which limits their influence on catalytic turnover.…”

Section: 2mentioning

confidence: 99%

Selective Hydrogenation of Phenol Catalyzed by Palladium on High-Surface-Area Ceria at Room Temperature and Ambient Pressure

et al. 2015

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Palladium supported on high-surface-area ceria effectively catalyzes the hydrogenation of phenol to cyclohexanone at atmospheric pressure and room temperature. Activation of H2 at Pd sites and phenol at surface ceria sites was investigated by probing the redox properties of the catalyst and studying the mechanism of phenol adsorption. Temperature-programmed reduction and pulsed chemisorption were used to examine the effects of prereduction temperature on catalyst dispersion and reducibility. A sharp effect of prereduction temperature on catalytic activity was observed. This dependence is rationalized as a result of interactions between palladium and ceria, which under reducing conditions enhance palladium dispersion and create different types of environments around the Pd active sites and of encapsulation of the catalyst caused by support sintering at high temperatures. Temperature-programmed diffuse reflectance infrared Fourier transform spectroscopy revealed that phenol undergoes dissociative adsorption on ceria to yield ceriumbound phenoxy and water. Reduction of the chemisorbed phenoxy species decreases the number of protonaccepting sites on the surface of ceria and prevents further dissociative adsorption. Subsequent phenol binding proceeds through physisorption, which is a less active binding mode for reduction by hydrogen. High activity can be restored upon regeneration of proton acceptor sites via reoxidation/reduction of the catalyst. ABSTRACT: Palladium supported on high-surface-area ceria effectively catalyzes the hydrogenation of phenol to cyclohexanone at atmospheric pressure and room temperature. Activation of H 2 at Pd sites and phenol at surface ceria sites was investigated by probing the redox properties of the catalyst and studying the mechanism of phenol adsorption. Temperature-programmed reduction and pulsed chemisorption were used to examine the effects of prereduction temperature on catalyst dispersion and reducibility. A sharp effect of prereduction temperature on catalytic activity was observed. This dependence is rationalized as a result of interactions between palladium and ceria, which under reducing conditions enhance palladium dispersion and create different types of environments around the Pd active sites and of encapsulation of the catalyst caused by support sintering at high temperatures. Temperature-programmed diffuse reflectance infrared Fourier transform spectroscopy revealed that phenol undergoes dissociative adsorption on ceria to yield cerium-bound phenoxy and water. Reduction of the chemisorbed phenoxy species decreases the number of proton-accepting sites on the surface of ceria and prevents further dissociative adsorption. Subsequent phenol binding proceeds through physisorption, which is a less active binding mode for reduction by hydrogen. High activity can be restored upon regeneration of proton acceptor sites via reoxidation/reduction of the catalyst.

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“…[44] Beispielsweise wurde die chemoselektive Hydrierung von Phenol (27) [46] und analytische Te chniken (Rh-K-edge-XAFS,S TEM, IR) umfasst, zeigte,d ass Rhodium-Nanopartikel die aktive Spezies sind. Während in der Arenhydrierung Carbonsäurederivate im Allgemeinen toleriert werden, werden Ketone oder Aldehyde normalerweise bevorzugt gegenüber Arenen hydriert.…”

Section: Bevorzugte Hydrierung Von Arenen In Gegenwart Leicht Reduzieunclassified

Die selektive Arenhydrierung bietet einen direkten Zugang zu gesättigten Carbo‐ und Heterocyclen

et al. 2019

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Die Arenhydrierung bietet einen direkten Zugang zu gesättigten Carbo‐ und Heterocyclen und kann daher zur Verkürzung von Synthesewegen genutzt werden. Diese nützliche Transformation wird industriell verwendet und sollte weitere Durchbrüche in den angewandten Wissenschaften ermöglichen. Von zentraler Bedeutung für die Anwendung bei der Herstellung komplexer Moleküle ist die Kontrolle der Diastereo‐, Enantio‐ und Chemoselektivität. Im Allgemeinen ergibt die Hydrierung multisubstituierter Arene überwiegend das cis‐Isomer. Die Enantiokontrolle kann über chirale Auxiliare, Brønsted‐Säuren oder Übergangsmetallkatalysatoren erfolgen. Jüngere Arbeiten zeigen hoch chemoselektive Transformationen. Derartige Verfahren und die zugrunde liegenden Strategien werden hier erläutert, wobei der Schwerpunkt auf präparativ nützlichen Reaktion mit leicht verfügbaren Katalysatoren liegt.

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Selective hydrogenation of phenol and related derivatives

Abstract: The selective hydrogenation of phenol and related derivatives to the corresponding cycloketones requires rationally designed catalysts, which have attracted significant attention.

Cited by 117 publications

References 136 publications

On the Reactivity of Dihydro‐p‐coumaryl Alcohol towards Reductive Processes Catalyzed by Raney Nickel

On the Reactivity of Dihydro‐p‐coumaryl Alcohol towards Reductive Processes Catalyzed by Raney Nickel

Selective Hydrogenation of Phenol Catalyzed by Palladium on High-Surface-Area Ceria at Room Temperature and Ambient Pressure

Die selektive Arenhydrierung bietet einen direkten Zugang zu gesättigten Carbo‐ und Heterocyclen

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