Cross aldol condensation of acetaldehyde and formaldehyde in the presence of bifunctional systems

Dashko, L. V.; Дмитриев, Д. В.; Pestov, S.; Флид, В. Р.

doi:10.1134/s1070428014120021

Cited by 7 publications

(2 citation statements)

References 1 publication

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“…Variation of the catalyst can also be successful; for example, acids activate hydrogen in the ‐CH 2 ‐ group in butanone whereas bases activate the ‐CH 3 group . Solvents have been reported to significantly affect selectivity in some cases, for example, the enantioselectivity in the Mukayama aldol reaction or the diastereoselectivity in the reaction of tert ‐butyl acetate and 2‐phenyl propanal . While successful, these methods are not necessarily suitable for large scale processing.…”

Section: Introductionmentioning

confidence: 99%

“…[21] Solvents have been reportedt osignificantlya ffect selectivity in some cases,f or example, the enantioselectivity in the Mukayama aldol reaction [22] or the diastereoselectivity in the reactiono ftert-butyl acetate and 2-phenyl propanal. [23][24][25][26][27] While successful, these methods are not necessarily suitable for large scale processing.…”

Section: Introductionmentioning

confidence: 99%

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Intraparticle Diffusional versus Site Effects on Reaction Pathways in Liquid‐Phase Cross Aldol Reactions

et al. 2018

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Chemo- and regioselectivity in a heterogeneously catalyzed cross aldol reaction were directed by tuning the nature of the sites, textural properties, and reaction conditions. Catalysts included sulfonic acid-functionalized resins or SBA-15 with varying particle size or pore diameter, H-BEA zeolites, and Sn-BEA zeotype; conditions were 25 °C to 170 °C in organic media. Benzaldehyde and 2-butanone yielded branched (reaction at -CH - of butanone) and linear (reaction at -CH ) addition and condensation products; and fission of the branched aldol led to β-methyl styrene and acetic acid. Strong acids promoted the dehydration step, and regioselectivity originated from preferred formation of the branched aldol. Both, resins and functionalized SBA-15 materials yielded predominantly the branched condensation product, unless particle morphology or temperature moved the reaction into the diffusion-limited regime, in which case more fission products were formed, corresponding to Wheeler Type II selectivity. For H-form zeolites, fission of the branched aldol competed with dehydration of the linear aldol, possibly because weaker acidity or steric restrictions prevented dehydration of the branched aldol.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Intraparticle Diffusional versus Site Effects on Reaction Pathways in Liquid‐Phase Cross Aldol Reactions

et al. 2018

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Synergistic Catalysis by MgO Induced Acid‐Base Bifunctional Sites for Cross Condensation of HCHO and Acetaldehyde

Wang,

Shi,

et al. 2024

ChemCatChem

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Acid‐base synergistic catalysis greatly enhances the performance of MgO‐based catalysts in the Aldol condensation. Here, the effect of acid‐base strength/concentration/proportion and the synergistic catalysis on the performance of cross condensation between HCHO and acetaldehyde were studied. The NH3/CO2‐TPD results suggested that weak acidic sites combined with medium basic sites were beneficial for the cross condensation. The loading of MgO nanocrystals on SiO2 induced the generation of new acidic sites (Mg‐O‐Si). Combined with the inherent basic sites (Mg‐O‐Mg) and Mg‐O‐Si, the acid‐base bifunctions sites could catalyse the cross condensation of HCHO and acetaldehyde synergistically. The appropriate proportion of acidic/basic sites (10/1) is critical for the cross condensation in the presence of vast water in formalin. The effect of reaction parameters, including the molar ratio of substrates, reaction temperature, liner velocity and weight hourly space velocity, were investigated for the cross condensation. The results showed that 10 wt% MgO/SiO2 catalyst possessed the highest catalytic activity (57.9% conversion of acetaldehyde and 84.3% selectivity of acrolein) under the optimal reaction parameters among the investigated catalysts. The MgO/SiO2 can be reused and recovered its catalytic performance after in‐situ regeneration in air to remove the carbon deposition.

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Coupled process of aldol condensation/hydrogenation of methyl ethyl ketone in the presence of a bifunctional heterogeneous catalyst

et al. 2022

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Cross aldol condensation of acetaldehyde and formaldehyde in the presence of bifunctional systems

Cited by 7 publications

References 1 publication

Intraparticle Diffusional versus Site Effects on Reaction Pathways in Liquid‐Phase Cross Aldol Reactions

Intraparticle Diffusional versus Site Effects on Reaction Pathways in Liquid‐Phase Cross Aldol Reactions

Synergistic Catalysis by MgO Induced Acid‐Base Bifunctional Sites for Cross Condensation of HCHO and Acetaldehyde

Coupled process of aldol condensation/hydrogenation of methyl ethyl ketone in the presence of a bifunctional heterogeneous catalyst

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