Crossing the Borders Between Homogeneous and Heterogeneous Catalysis: Developing Recoverable and Reusable Catalytic Systems

Corma, Avelino; Garcı́a, Hermenegildo

doi:10.1007/s11244-008-9056-5

Cited by 148 publications

(96 citation statements)

References 119 publications

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“…Despite these disadvantages, heterogeneous catalysts are valued because they allow easy separation of products and can be reused for extended periods of time. [6] Given its importance as a C-C bond-forming reaction, the aldol condensation has been a common target for catalyst design. [7][8][9][10][11] This reaction is performed in organisms by aldolases, which activate donor ketones with the amino group of a highly conserved lysine, to give enamines.…”

Section: Introductionmentioning

confidence: 99%

Substrate inhibition in the heterogeneous catalyzed aldol condensation: A mechanistic study of supported organocatalysts

Kandel

Althaus

Peeraphatdit

et al. 2012

Journal of Catalysis

137

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In this study, we demonstrate how materials science can be combined with the established methods of organic chemistry to find mechanistic bottlenecks and redesign heterogeneous catalysts for improved performance. By using solid-state NMR, infrared spectroscopy, surface and kinetic analysis, we prove the existence of a substrate inhibition in the aldol condensation catalyzed by heterogeneous amines. We show that modifying the structure of the supported amines according to the proposed mechanism dramatically enhances the activity of the heterogeneous catalyst. We also provide evidence that the reaction benefits significantly from the surface chemistry of the silica support, which plays the role of a co-catalyst, giving activities up to two orders of magnitude larger than those of homogeneous amines. This study confirms that the optimization of a heterogeneous catalyst depends as much on obtaining organic mechanistic information as it does on controlling the structure of the support. Disciplines Materials Chemistry | Other Chemistry | Physical ChemistryComments NOTICE: this is the author's version of a work that was accepted for publication in Journal of Catalysis. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Catalysis, [291, (2012) AbstractIn this study we demonstrate how materials science can be combined with the established methods of organic chemistry to find mechanistic bottlenecks and redesign heterogeneous catalysts for improved performance. By using solid-state NMR, infrared spectroscopy, surface and kinetic analysis, we prove the existence of a substrate inhibition in the aldol condensation catalyzed by heterogeneous amines. We show that modifying the structure of the supported amines according to the proposed mechanism dramatically enhances the activity of the heterogeneous catalyst. We also provide evidence that the reaction benefits significantly from the surface chemistry of the silica support, which plays the role of a co-catalyst, giving activities up to two orders of magnitude larger than those of homogeneous amines. This study confirms that the optimization of a heterogeneous catalyst depends as much on obtaining organic mechanistic information as it does on controlling the structure of the support.

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Section: Introductionmentioning

confidence: 99%

Substrate inhibition in the heterogeneous catalyzed aldol condensation: A mechanistic study of supported organocatalysts

Kandel

Althaus

Peeraphatdit

et al. 2012

Journal of Catalysis

137

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“…Reactions with Pd(NO3)2-2H2O, Pd(PPh3)4, or Pd(PPh3)2Cl2 provided moderate yields of bisarylacetylene (entries 5, 9, and 10, respectively). Reactions performed with various organic bases in a 3:1 dioxane:H2O mixture were also evaluated (entries [12][13][14]. The reaction with DBU provided an excellent yield of the desired product without any side products.…”

Section: Resultsmentioning

confidence: 99%

“…[7][8][9] Recently, many reports have described nano-sized, semiheterogeneous catalysts, the properties of which border between those of homogeneous and heterogeneous catalysts. [10][11][12] Separation of spent heterogeneous catalyst from a product mixture is easier than in the case of homogeneous systems. Heterogeneous catalysts also help to minimize waste derived from the reaction workup, thereby contributing to the development of green chemical processes.…”

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confidence: 99%

Synthesis of Functionalized Bisarylacetylene Derivatives from Acetylene Gas Over Nano-sized Carbon Ball Supported Palladium Catalyst

Yum

Son²,

Kim³

et al. 2010

Bulletin of the Korean Chemical Society

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“…Metals supported on magnetic nano particles create a new approach to the world of catalysts [4]. By nascent of such catalysts, it became possible to bring the advantages of both kinds of catalysts (homogeneous and heterogeneous) together in a one magnetic nano catalyst [5]. It means one can profit from sustainability with high yields and easy work up [6].…”

Section: Introductionmentioning

confidence: 99%

Nitro compound reduction in the presence of robust palladium immobilized on modified magnetic Fe3O4 nanoparticles as a recoverable catalyst

Dadras

Naimi‐Jamal

Moghaddam

et al. 2017

Proceedings of the 21st International Electronic Conference on Synthetic Organic Chemistry

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We report the synthesis of recoverable magnetic nano catalyst Pd@ Fe 3 O 4 and its utility as a recyclable catalyst for reduction of nitro group. The catalyst is easily removed from the reaction media by an external magnetic field and can be re-used for at least 10 times without any considerable loss in its activity. The catalyst was characterized by scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), inductively coupled plasma spectroscopy (ICP), Fourier transform infrared spectroscopy (FTIR), CHN analysis, and vibrating sample magnetometery (VSM).

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Crossing the Borders Between Homogeneous and Heterogeneous Catalysis: Developing Recoverable and Reusable Catalytic Systems

Abstract: Homogeneous and heterogeneous catalysis have developed independently as two separate disciplines.

Cited by 148 publications

References 119 publications

Substrate inhibition in the heterogeneous catalyzed aldol condensation: A mechanistic study of supported organocatalysts

Substrate inhibition in the heterogeneous catalyzed aldol condensation: A mechanistic study of supported organocatalysts

Synthesis of Functionalized Bisarylacetylene Derivatives from Acetylene Gas Over Nano-sized Carbon Ball Supported Palladium Catalyst

<strong>Nitro compound reduction in the presence of robust palladium immobilized on modified magnetic Fe<sub>3</sub>O<sub>4</sub> nanoparticles as a recoverable catalyst</strong>

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