Surface reactions of acetone, acetylene and methylbutynol on a yttrium-modified magnesium oxide catalyst

Fouad, Nasr E.; Thomasson, P; Knözinger, Helmut

doi:10.1016/s0926-860x(99)00461-5

Cited by 32 publications

(39 citation statements)

References 12 publications

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“…The bands belonging to M-OH are present near 1100 cm À 1 [28]. The bands related to physisorbed water or H-bonded hydroxyl groups located at 3441 and 1651 cm À 1 [30][31][32] were detected. The band present at 3865 is related to OHstretching of surface hydroxyl groups [33] Fig.…”

Section: Xrd Investigation Of Pure and Doped Solidsmentioning

confidence: 99%

Catalytic conversion of isopropanol over NiO/MgO system doped with Li2O

2004

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Section: Xrd Investigation Of Pure and Doped Solidsmentioning

confidence: 99%

Catalytic conversion of isopropanol over NiO/MgO system doped with Li2O

2004

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“…The band position of the surface OH groups on MgO agrees well with that Fouad et al [88]. The small increase in the surface OH stretch in Figure 4.9b was likely the result of ethanol dissociative chemisorption, but we cannot rule out the potential role of water produced from ethanol dehydration.…”

Section: Co 2 Adsorption Microcalorimetrysupporting

confidence: 90%

“…A prior report has indicated that addition of Y 3+ to MgO increases deactivation since the more Lewis acidic metal ion helps stabilize reaction intermediates that lead to acetone coupling products [88]. In our study with MgO and ZrO 2 mixed oxides, all samples containing MgO deactivated quickly.…”

Section: Acetone Coupling and Condensationmentioning

confidence: 46%

“…Examples of bifunctional solids include Y 3+ added to MgO [88], Mg:Al mixed oxides [39,41,68,89], amorphous aluminophosphate [40], Cs/ZrO 2 [90] and Mg:Zr mixed oxides [91,92]. The promotion of the reaction on bifunctional catalysts is thought in part to be the result of the stabilization of an intermediate through a Lewis acid interaction.…”

Section: Scheme 112mentioning

confidence: 99%

“…The promotion of the reaction on bifunctional catalysts is thought in part to be the result of the stabilization of an intermediate through a Lewis acid interaction. This interaction also allows large networks of aldolization products to form at elevated temperatures, since a strong interaction between the oxygenated intermediates and the Lewis acid sites prevents desorption, especially when multiple functional groups exist in one molecule [88].…”

Section: Scheme 112mentioning

confidence: 99%

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Carbon-Carbon Bond Forming Reactions Over Metal Oxide Catalysts

Kozlowski¹

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Alcohol coupling, also known as the Guerbet reaction, is a potentially important process to increase the value of short chain alcohols. Metal oxides, metal phosphates and supported transition metals like copper are some examples of heterogeneous catalysts for the reaction.However, the wide variety of catalyst compositions, reaction conditions, and reactor configurations used to study the reaction complicates a direct comparison of various catalysts.Herein, rates over different catalysts will be compared. One existing gap in the current literature is a thorough comparison of the surface acid and base properties of catalysts employed in the Guerbet coupling of alcohols. In this work, various bifunctional materials were synthesized, characterized, and used in Guerbet alcohol coupling and other probe reactions of acid and base catalysts.One well-studied reaction catalyzed by acids and bases is transesterification. Two series of Mg:Zr mixed oxides, prepared by either co-precipitation or sol-gel synthesis, were characterized and evaluated in the base-catalyzed transesterification of tributyrin with methanol.A co-precipitated Mg-rich mixed oxide catalyst with Mg:Zr 11:1 was approximately 300% more active than MgO on a surface area basis, whereas pure ZrO 2 was inactive for the reaction. To explore the nature of the activity enhancement, samples were characterized by X-ray diffraction, N 2 adsorption, CO 2 adsorption microcalorimetry and DRIFTS of adsorbed CO 2 and CH 3 OH.Although the sol-gel synthesis method provided better atomic-level mixing of Mg and Zr, the resulting catalysts were not as effective as mixed oxides prepared by co-precipitation. The most active mixed oxide (Mg:Zr 11:1) exhibited a high initial heat of CO 2 adsorption and modified modes of methanol adsorption compared to MgO. However, the CO 2 adsorption capacity did not correlate to catalyst activity.

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Influence of the Precipitation Method on Acid–Base‐Catalyzed Reactions over Mg–Zr Mixed Oxides

et al. 2013

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To examine the promotional effect that zirconia has on magnesia in catalysis, mixed oxides were prepared by coprecipitation under controlled‐pH conditions or rising‐pH conditions. The resulting mixed oxides were characterized by using NH3 and CO2 adsorption microcalorimetry, X‐ray diffraction, and scanning electron microscopy. The samples were also tested as catalysts for transesterification of tributyrin with methanol, coupling of acetone, and conversion of ethanol to ethene, ethanal, and butanol. Zirconia promoted the activity of MgO for both transesterification and acetone coupling reactions, presumably by exposing new acid–base pairs at the surface. During ethanol conversion, however, zirconia promoted the dehydration reactions. Characterization and reactivity results suggest that a Mg‐Zr sample prepared by controlled‐pH precipitation exposes more ZrO2 than a sample prepared by the rising‐pH method.

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Surface reactions of acetone, acetylene and methylbutynol on a yttrium-modified magnesium oxide catalyst

Cited by 32 publications

References 12 publications

Catalytic conversion of isopropanol over NiO/MgO system doped with Li2O

Catalytic conversion of isopropanol over NiO/MgO system doped with Li2O

Carbon-Carbon Bond Forming Reactions Over Metal Oxide Catalysts

Influence of the Precipitation Method on Acid–Base‐Catalyzed Reactions over Mg–Zr Mixed Oxides

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