Aerobic oxidation of aldehydes under ambient conditions using supported gold nanoparticle catalysts

Marsden, Charlotte C.; Taarning, Esben; Hansen, David; Johansen, Lars; Kegnæs, Søren; Egeblad, Kresten; Christensen, Claus H.

doi:10.1039/b712171g

Cited by 156 publications

(99 citation statements)

References 18 publications

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“…We used a commercially available catalyst that had been pretreated by the manufacturer to ensure that particles were of appropriate size (2-4 nm) to yield active CO oxidation catalysts. This allows us to separate the effects of thermal treatments from those necessary for preparing active particles because the particle size does not change as a function of the pretreatment [65][66][67]. Further, this catalyst has proven to be active and stable in spite of being stored over long periods of time, making it a useful benchmark material for comparing pretreatments and other catalysts.…”

Section: Discussionmentioning

confidence: 99%

CO oxidation over Au/TiO2 catalyst: Pretreatment effects, catalyst deactivation, and carbonates production

Lopez

Powell

Panthi

et al. 2013

Journal of Catalysis

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a b s t r a c tA commercially available Au/TiO 2 catalyst was subjected to a variety of thermal treatments in order to understand how variations in catalyst pretreatment procedures might affect CO oxidation catalysis. Catalytic activity was found to be inversely correlated to the temperature of the pretreatment. Infrared spectroscopy of adsorbed CO experiments, followed by a Temkin analysis of the data, indicated that the thermal treatments caused essentially no changes to the electronics of the Au particles; this, and a series of catalysis control experiments, and previous transmission electron microscopy (TEM) studies ruled out particle growth as a contributing factor to the activity loss. Fourier transform infrared (FTIR) spectroscopy showed that pretreating the catalyst results in water desorption from the surface, but the observable water loss was similar for all the treatments and could not be correlated with catalytic activity. A Michaelis-Menten kinetic treatment indicated that the main reason for deactivation is a loss in the number of active sites with little changes in their intrinsic activity. In situ FTIR experiments during CO oxidation showed extensive buildup of carbonate-like surface species when the pretreated catalysts were contacted with the feed gas. A semi-quantitative infrared spectroscopy method was developed for comparing the amount of carbonates present on each catalyst; results from these experiments showed a strong correlation between the steady-state catalytic activity and amount of surface carbonates generated during the initial moments of catalysis. Further, this experimental protocol was used to show that the carbonates reside on the titania support rather than on the Au, as there was no evidence that they poison Au-CO binding sites. The role of the carbonates in the reaction scheme, their potential role in catalyst deactivation, and the role of surface hydroxyls and water are discussed.

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Section: Discussionmentioning

confidence: 99%

CO oxidation over Au/TiO2 catalyst: Pretreatment effects, catalyst deactivation, and carbonates production

Lopez

Powell

Panthi

et al. 2013

Journal of Catalysis

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“…In particular, as for the oxidative esterification of alcohol to methyl esters, Christensen et al described a practically, and potentially economically, attractive route to furnish esters starting from aldehydes. They for example oxidized acrolein-aldehyde of allyl alcohol, in methanol under oxygen atmosphere using commercial Au/TiO 2 (1%, supplied by Mintek) supported on titanium oxide, producing methyl acrylate with 87% selectivity at 97% conversion in the presence of NaOMe [63]. Unfortunately, no relationship between the extremely high activity and the Au size was found by the authors [27,63].…”

Section: Role Of the Gold Sizementioning

confidence: 99%

“…They for example oxidized acrolein-aldehyde of allyl alcohol, in methanol under oxygen atmosphere using commercial Au/TiO 2 (1%, supplied by Mintek) supported on titanium oxide, producing methyl acrylate with 87% selectivity at 97% conversion in the presence of NaOMe [63]. Unfortunately, no relationship between the extremely high activity and the Au size was found by the authors [27,63]. Corma et al [28] compared several gold catalysts on different supports, but with similar gold particle size in the oxidative esterification of 5-hydroxymethyl-2-furfural into 2,5-dimethylfuroate and found that Au supported on nanoparticulated ceria gave the best performances.…”

Section: Role Of the Gold Sizementioning

confidence: 99%

Biomass Derived Chemicals: Furfural Oxidative Esterification to Methyl-2-furoate over Gold Catalysts

et al. 2016

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Abstract:The use of heterogeneous catalysis to upgrade biomass wastes coming from lignocellulose into higher value-added chemicals is one of the most explored subjects in the prospective vision of bio-refinery. In this frame, a lot of interest has been driven towards biomass-derived building block molecules, such as furfural. Gold supported catalysts have been successfully proven to be highly active and selective in the furfural oxidative esterification to methyl-2-furoate under mild conditions by employing oxygen as benign oxidant. Particular attention has been given to the studies in which the reaction occurs even without base as co-catalyst, which would lead to a more green and economically advantageous process. The Au catalysts are also stable and quite easily recovered and represent a feasible and promising route to efficiently convert furfural to methyl-2-furoate to be scaled up at industrial level.

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“…They further indicate that various combinations of an aldehyde and volatile compounds from other chemical classes hold the potential to yield bioactive blends. Shortchain aldehydes might rapidly oxidize under ambient conditions (Larkin 1990;Marsden et al 2008), suggesting that the addition of antioxidative agents might be required to increase the long-lasting effect of these aldehydes in synthetic blends. Developing different synthetic blends will be advantageous for future monitoring of the oriental fruit moth, as efficacy of synthetic blends can be context-specific, i.e., higher or lower depending on the host plant species in the orchard (Light et al 2001;Light and Knight 2005;Lu et al 2012).…”

Section: Common Volatiles and Attraction Of Oriental Fruit Mothmentioning

confidence: 99%

Season-Long Volatile Emissions from Peach and Pear Trees In Situ, Overlapping Profiles, and Olfactory Attraction of an Oligophagous Fruit Moth in the Laboratory

2013

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Insect herbivores that have more than one generation per year and reproduce on different host plants are confronted with substantial seasonal variation in the volatile blends emitted by their hosts. One way to deal with such variation is to respond to a specific set of compounds common to all host plants. The oriental fruit moth Cydia (=Grapholita) molesta is a highly damaging invasive pest. The stone fruit peach (Prunus persica) is its primary host, whereas pome fruits such as pear (Pyrus communis) are considered secondary hosts. In some parts of their geographic range, moth populations switch from stone to pome fruit orchards during the growing season. Here, we tested whether this temporal switch is facilitated by female responses to plant volatiles. We collected volatiles from peach and pear trees in situ and characterized their seasonal dynamics by gas chromatography-mass spectrometry. We also assessed the effects of the natural volatile blends released by the two plant species on female attraction by using Y-tube olfactometry. Finally, we related variations in volatile emissions to female olfactory responses. Our results indicate that the seasonal host switch from peach to pear is facilitated by the changing olfactory effect of the natural volatile blends being emitted. Peach volatiles were only attractive early and mid season, whereas pear volatiles were attractive from mid to late season. Blends from the various attractive stages shared a common set of five aldehydes, which are suggested to play an essential role in female attraction to host plants. Particular attention should be given to these aldehydes when designing candidate attractants for oriental fruit moth females.

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Aerobic oxidation of aldehydes under ambient conditions using supported gold nanoparticle catalysts

Cited by 156 publications

References 18 publications

CO oxidation over Au/TiO2 catalyst: Pretreatment effects, catalyst deactivation, and carbonates production

CO oxidation over Au/TiO2 catalyst: Pretreatment effects, catalyst deactivation, and carbonates production

Biomass Derived Chemicals: Furfural Oxidative Esterification to Methyl-2-furoate over Gold Catalysts

Season-Long Volatile Emissions from Peach and Pear Trees In Situ, Overlapping Profiles, and Olfactory Attraction of an Oligophagous Fruit Moth in the Laboratory

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