Acetaldehyde adsorption on aluminium oxide

Сокольский, Д. В.; Vozdvizhenskii, V.F.; Kuanyshev, A. Sh.; Кобец, А. В.

doi:10.1007/bf02279785

Cited by 4 publications

(6 citation statements)

References 3 publications

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“…Previous investigations of the adsorption of acetaldehyde on the surfaces of silica, , alumina, , and silica−alumina catalysts 30 have also demonstrated the existence of a strongly bound form of acetaldehyde. This species generally retains vibrational modes similar to that of gas-phase acetaldehyde, though it cannot be removed by prolonged evacuation near room temperature .…”

Section: Discussionmentioning

confidence: 93%

“…Similar conclusions have been reached previously for the adsorption of acetaldehyde on metal oxides. [28][29][30] While the C-H stretches are unaffected, the δ(CH 3 ) mode is perturbed upon adsorption of acetaldehyde, especially at low exposures on rutile TiO 2 (spectrum a, Figure 4). The mode is shifted to lower frequencies and is broadened from its characteristic sharp appearance; 44 it sharpens with increasing exposure as the more weakly bound state is populated.…”

Section: Discussionmentioning

confidence: 99%

“…This species generally retains vibrational modes similar to that of gasphase acetaldehyde, though it cannot be removed by prolonged evacuation near room temperature. 29 On these materials this state has been attributed to a strong hydrogen-bonding interaction between surface hydroxyl groups and the carbonyl oxygen of acetaldehyde. 27,28 Although the materials above are associated with acidcatalyzed reactions, such interactions are possible on all metal oxides containing hydroxyl groups.…”

Section: Discussionmentioning

confidence: 99%

“…With added aluminum, the adsorption of acetaldehyde was accompanied by condensation reactions. Additional studies have been performed on silica, γ-alumina, and silica−alumina and more recently on several other oxide materials. ,, Each study concluded that the initial adsorption of acetaldehyde occurs in one of two modes: a hydrogen-bonded complex between surface OH groups and the carbonyl oxygen or a weak coordination complex between surface cations and the carbonyl compound.…”

Section: Introductionmentioning

confidence: 99%

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Competition between Acetaldehyde and Crotonaldehyde during Adsorption and Reaction on Anatase and Rutile Titanium Dioxide

1999

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The adsorption of acetaldehyde and crotonaldehyde on the anatase and rutile polymorphs of TiO2 has been investigated with Fourier transform infrared spectroscopy (FTIR). Chemisorption of acetaldehyde on TiO2 involves a strong interaction between the surface and the carbonyl oxygen, causing a significant shift in the location of the ν(CO) vibrational mode to lower frequencies; no interaction with surface hydroxyl groups was observed. Capacities for acetaldehyde and crotonaldehyde adsorption under conditions relevant to aldolization reactions were determined in a novel reactor system providing simultaneous mass measurements and mass spectral analysis of gas-phase products. The coverage of acetaldehyde irreversibly adsorbed on TiO2 was similar to values previously reported for the adsorption of alcohols; coverages of crotonaldehyde were approximately 60% of those for acetaldehyde. Both gas-phase and surface analyses indicate that formation of crotonaldehyde by aldol condensation of acetaldehyde occurs on rutile TiO2 at temperatures as low as 313 K. This reaction was not observed on anatase at these conditions; higher temperatures were required. The production of crotonaldehyde on rutile at 313 K diminished with increasing exposure of acetaldehyde. Acetaldehyde and crotonaldehyde adsorbed in a similar fashion on both anatase and rutile, and either aldehyde could displace the other from the surface layer. Accordingly, the surface concentrations of adsorbed acetaldehyde and crotonaldehyde mirror those in the gas phase. Upon heating an adsorbed layer of acetaldehyde, small amounts of ethoxide and acetate species were formed, possibly from a Cannizzaro-type disproportionation reaction. The similarity of these results to those of studies on TiO2 single crystals illustrates the applicability of properly chosen metal oxide single-crystal surfaces as models for polycrystalline powders. Both demonstrate that the chemistry of aldehydes on TiO2 can be successfully explained in terms of the reactions of a few key surface species.

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Section: Discussionmentioning

confidence: 93%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Competition between Acetaldehyde and Crotonaldehyde during Adsorption and Reaction on Anatase and Rutile Titanium Dioxide

1999

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“…The octahedral Lewis acid sites present solely on the a-Al 2 O 3 surface are significantly weaker than the tetrahedral ones which can be found on the surface of g-Al 2 O 3 [15]. This latter kind of alumina is often tested as ketones and aldehydes adsorbent capable to transform these molecules into the corresponding products [16][17][18].…”

Section: Samplementioning

confidence: 99%

Synthesis of carbon/α-Al2O3 composite adsorbents for the elimination of methyl-ethyl ketone vapour

Kuśtrowski¹,

Molenda²,

Janus³

et al. 2010

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a-Al 2 O 3 has been modified by the deposition of different amounts of polyacrylonitrile (PAN) via precipitation radical polymerization in an aqueous suspension. Carbonization of the product performed in an inert atmosphere at 350°C resulted in obtaining of a carbon layer supported on the surface of a-Al 2 O 3. The content of carbon in the composites was determined by temperature-programmed oxidation, whereas textural properties of the synthesized samples were studied by low-temperature sorption of N 2 (BET). The carbon/a-Al 2 O 3 composites appeared to be effective adsorbents of methyl ethyl ketone vapour.

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