Selective oxidation of allylic alcohols over highly ordered Pd/meso-Al2O3 catalysts

Parlett, Christopher M. A.; Durndell, Lee J.; Wilson, Karen; Bruce, Duncan W.; Hondow, Nicole; Lee, Adam F.

doi:10.1016/j.catcom.2013.07.005

Cited by 32 publications

(21 citation statements)

References 43 publications

(64 reference statements)

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“…The surface PdO content quantified in Table 1 was significantly higher than that observed for comparable metal loadings over mesoporous silica or alumina, consistent with the higher palladium dispersion. We have previously noted that these properties are closely correlated over alumina supports [24], and …”

Section: Materials Characterisationmentioning

confidence: 82%

“…Time-resolved, liquid and vapour phase XAS measurements [16][17][18][19] on carbon and oxide supported nanoparticles respectively, and complementary in-situ XPS measurements over O/Pd(111) single crystals [20,21] have highlighted PdO reduction to metallic palladium as a potential deactivation pathway, and hence the importance of generating highly dispersed nanoparticles which favour an oxide phase [20,[22][23][24].…”

Section: Introductionmentioning

confidence: 99%

“…Ordered mesoporous silicas, prepared via surfactant templating routes [30,31], possess high surface areas and interconnected mesopores that permit the synthesis of highly oxidised 1-2 nm Pd particles [22,23]. We recently discovered that mesoporous alumina is superior to silica for stabilising sub-nanometre palladium clusters and even atomicallydispersed Pd 2+ centres [24,32], presumably reflecting a stronger metal-support interaction (a function of the acid/base character of metal oxides [33][34][35]). Unfortunately, pure alumina supports are plagued by low hydrothermal stability, and typically significantly lower surface areas and mesopore ordering than their silica counterparts.…”

Section: Introductionmentioning

confidence: 99%

“… Operando XAS confirms cinnamyl alcohol selox occurs over a PdO active species, which is prone to on-stream reduction and associated catalyst deactivation under static oxygen. [20,21] have highlighted PdO reduction to metallic palladium as a potential deactivation pathway, and hence the importance of generating highly dispersed nanoparticles which favour an oxide phase [20,[22][23][24]. …”

mentioning

confidence: 99%

“…HAADF-STEM shows uniformly distributed nanoparticles with a narrow size range and mean particle diameter of 1.1 (±0.5) nm, while bright field TEM shows that the ordered mesopore architecture of the Al-SBA-15(4) support is preserved, with elemental analysis (in STEM configuration) confirming the presence of both Pd and Al throughout the pore network. Palladium metal dispersions were used to estimate average particle diameters, assuming a spherical morphology, for comparison against similar Pd loadings on mesoporous alumina and SBA-15 supports [22,24]. Pd/Al-SBA-15(4) was probed by XPS, with both metal and oxide observed ( Figure S3).…”

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confidence: 99%

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Alumina-grafted SBA-15 as a high performance support for Pd-catalysed cinnamyl alcohol selective oxidation

et al. 2014

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eprints@whiterose.ac.uk https://eprints.whiterose.ac.uk/ Reuse Unless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version -refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher's website. TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request. Operando, liquid phase XAS highlights the interplay between dissolved oxygen and the oxidation state of palladium nanoparticles dispersed over Al-SBA-15 towards on-stream reduction: ambient pressures of flowing oxygen are sufficient to hinder palladium oxide reduction to metal, enabling a high selox activity to be maintained, whereas rapid PdO reduction and concomitant catalyst deactivation occurs under static oxygen.Selectivity to the desired cinnamaldehyde product mirrors these trends in activity, with flowing oxygen minimising C-O cleavage of the cinnamyl alcohol reactant to trans--methylstyrene, and of cinnamaldehyde decarbonylation to styrene. Highlights: An ultrathin alumina coating has been grafted onto a SBA-15 mesoporous silica architecture. Pd impregnated Al-SBA-15 materials are superior catalysts for the aerobic selox of allylic alcohols to aldehydes compared to pure silica or alumina supports.  Operando XAS confirms cinnamyl alcohol selox occurs over a PdO active species, which is prone to on-stream reduction and associated catalyst deactivation under static oxygen. [20,21] have highlighted PdO reduction to metallic palladium as a potential deactivation pathway, and hence the importance of generating highly dispersed nanoparticles which favour an oxide phase [20,[22][23][24]. KeywordsTemperature-programmed desorption and XPS of crotyl alcohol (but-2-en-1-ol) and crotonaldehyde (but-2-en-1-al) over Pd(111) and palladium-rich Au/Pd surface alloys suggest deactivation arises from crotonaldehyde decarbonylation and subsequent site-blocking by strongly adsorbed propylidyne and CO [20,21]. Computational modelling predicts Pd(111) can also drive propanoic acid decarbonylation [25]. Vapour phase studies of crotyl alcohol oxidation show that such in-situ palladium reduction is reversible under oxidising environments [17,19], enabling selox to be maintained, however the ability of dissolved oxygen to preserve palladium as PdO during liquid phase selox is unknown. Experimental Catalyst synthesisThe parent SBA-15 silica framework was synthesised following the method of Zhao et al [30]. Pluronic P123 (10 g) was dissolved in water (75.5 ...

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Section: Materials Characterisationmentioning

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Alumina-grafted SBA-15 as a high performance support for Pd-catalysed cinnamyl alcohol selective oxidation

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Review on heterogeneous catalysts for the synthesis of perfumery chemicals via isomerization, acetalization and hydrogenation

Hartati

Firda

Bahruji

et al. 2021

Flavour & Fragrance J

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Synthetic fragrance has dominated the perfumery industry in recent decades due to the ability to produce perfumery ingredients on a large scale at a low cost. Extensive research in the field of synthetic perfumery chemical involved the utilization of catalysts to improve the productivity. This review will discuss recent advances of heterogeneous catalysts for the synthesis of perfumery chemicals as fragrance ingredients. Transition from homogeneous to heterogeneous catalysts will be included in order to provide insight into the benefits of heterogeneous catalysts to overcome the limitation of homogeneous reaction. Isomerization, acetalization and hydrogenation were identified as three main reactions for the synthesis of perfumery chemicals based on the number of reported work since 2000. This review will focus on α‐pinene and α‐pinene oxide as the main molecular substrates, however, different molecules, for example, linalool, citronellal and cinnamaldehyde will also be included. The synthesis, modification and possible mechanisms for the reactions involving zeolite, aluminosilicate, metal oxides, metal organic framework, monometallic and bimetallic nanoparticles as heterogeneous catalysts will be discussed. Discussion on isomerization and acetalization reactions will focus on the acidity and the porosity of the catalysts as the two main factors that determine the conversion and selectivity. For perfumery chemicals produced via hydrogenation reaction, the role of monometallic and bimetallic nanoparticles catalysts will be discussed in the chemoselective reduction of cinnamaldehyde and citronellal.

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Green Catalysts

Lee¹

2016

XAFS Techniques for Catalysts, Nanomaterials, and Surfaces

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Selective oxidation of allylic alcohols over highly ordered Pd/meso-Al2O3 catalysts

Cited by 32 publications

References 43 publications

Alumina-grafted SBA-15 as a high performance support for Pd-catalysed cinnamyl alcohol selective oxidation

Alumina-grafted SBA-15 as a high performance support for Pd-catalysed cinnamyl alcohol selective oxidation

Review on heterogeneous catalysts for the synthesis of perfumery chemicals via isomerization, acetalization and hydrogenation

Green Catalysts

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