Effect of the acid–base properties of the support on the performance of Pt catalysts in the partial hydrogenation of citral

Santiago-Pedro, Smid; Tamayo-Galván, Victoria; Viveros, T.

doi:10.1016/j.cattod.2013.04.032

Cited by 28 publications

(27 citation statements)

References 42 publications

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“…The appearance of the peak centered at 460 • C indicates the formation of acid sites formed, likely at the vicinity of the Pt nanoparticles. The formation of new acidic groups on the Pt/SiO 2 catalysts agrees with the literature data, but strongly depends on the catalyst preparation method [45][46][47]. …”

Section: Catalyst Characterizationsupporting

confidence: 78%

Highly Selective Continuous Flow Hydrogenation of Cinnamaldehyde to Cinnamyl Alcohol in a Pt/SiO2 Coated Tube Reactor

et al. 2018

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A novel continuous flow process for selective hydrogenation of α, β-unsaturated aldehyde (cinnamaldehyde, CAL) to the unsaturated alcohol (cinnamyl alcohol, COL) has been reported in a tube reactor coated with a Pt/SiO 2 catalyst. A 90% selectivity towards the unsaturated alcohol was obtained at the aldehyde conversion of 98.8%. This is a six-fold improvement in the selectivity compared to a batch process where acetals were the main reaction products. The increased selectivity in the tube reactor was caused by the suppression of acid sites responsible for the acetal formation after a short period on stream in the continuous process. In a fixed bed reactor, it had a similar acetal suppression phenomenon but showed lower product selectivity of about 47-72% due to mass transfer limitations. A minor change in selectivity and conversion caused by product inhibition was observed during the 110 h on stream with a turnover number (TON) reaching 3000 and an alcohol production throughput of 0.36 kg g Pt −1 day −1 in the single tube reactor. The catalysts performance after eight reaction cycles was fully restored by calcination in air at 400 • C. The tube reactors provide an opportunity for process intensification by increasing the reaction rates by a factor of 2.5 at the reaction temperature of 150 • C compared to 90 • C with no detrimental effects on catalyst stability or product selectivity.

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Section: Catalyst Characterizationsupporting

confidence: 78%

Highly Selective Continuous Flow Hydrogenation of Cinnamaldehyde to Cinnamyl Alcohol in a Pt/SiO2 Coated Tube Reactor

et al. 2018

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“…Guo et al have shown that confinement of Pt nanoclusters within the cavity of metal-organic frameworks also promotes CinnOH selectivity; steric constraints on the CinnALD geometry is believed to hinder C = C planar adsorption, again promoting C = O activation 29 . Despite this progress, kinetics of the CinnALD hydrogenation reaction network have not yet been mapped in detail over any heterogeneous catalyst, while for platinum there has been no systematic study on the impact of particle size (over a wide range) or H 2 pressure, or of support properties which influence not only CinnALD hydrogenation 30 but also crotonaldehyde 31 and citral hydrogenation 32 33 . Consequently the nature of the active site remains a matter for speculation, and little is known regarding the effect of substituents, or the extent to which mechanistic models can be extended to other conjugated aldehydes.…”

mentioning

confidence: 99%

Selectivity control in Pt-catalyzed cinnamaldehyde hydrogenation

Durndell

Parlett

Hondow

et al. 2015

Sci Rep

116

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Chemoselectivity is a cornerstone of catalysis, permitting the targeted modification of specific functional groups within complex starting materials. Here we elucidate key structural and electronic factors controlling the liquid phase hydrogenation of cinnamaldehyde and related benzylic aldehydes over Pt nanoparticles. Mechanistic insight from kinetic mapping reveals cinnamaldehyde hydrogenation is structure-insensitive over metallic platinum, proceeding with a common Turnover Frequency independent of precursor, particle size or support architecture. In contrast, selectivity to the desired cinnamyl alcohol product is highly structure sensitive, with large nanoparticles and high hydrogen pressures favoring C = O over C = C hydrogenation, attributed to molecular surface crowding and suppression of sterically-demanding adsorption modes. In situ vibrational spectroscopies highlight the role of support polarity in enhancing C = O hydrogenation (through cinnamaldehyde reorientation), a general phenomenon extending to alkyl-substituted benzaldehydes. Tuning nanoparticle size and support polarity affords a flexible means to control the chemoselective hydrogenation of aromatic aldehydes.

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“…This suggestion is also supported by known literature procedures, in which such lactams are prepared in neutral solvents by intramolecular amidation of esters with in-situ formed amino groups [32,33,116]. The significant effect of the support characteristics observed in this reaction may be attributed to the electronic charge transfer that occurred between metal and support, as was suggested to be the reason for the selectivities obtained in the competitive hydrogenation of different functional groups [117].…”

Section: Effect Of the Catalyst Supportsupporting

confidence: 76%

Asymmetric cascade reaction of 2-nitrophenylpyruvates over chirally modified platinum catalyst

Kovács

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Effect of the acid–base properties of the support on the performance of Pt catalysts in the partial hydrogenation of citral

Cited by 28 publications

References 42 publications

Highly Selective Continuous Flow Hydrogenation of Cinnamaldehyde to Cinnamyl Alcohol in a Pt/SiO2 Coated Tube Reactor

Highly Selective Continuous Flow Hydrogenation of Cinnamaldehyde to Cinnamyl Alcohol in a Pt/SiO2 Coated Tube Reactor

Selectivity control in Pt-catalyzed cinnamaldehyde hydrogenation

Asymmetric cascade reaction of 2-nitrophenylpyruvates over chirally modified platinum catalyst

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