Recyclable hydrotalcite clay catalysed Baylis–Hillman reaction

Srivastava, Vivek

doi:10.1007/s12039-013-0472-0

Cited by 14 publications

(4 citation statements)

References 14 publications

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“…151,176,177 The nanostructured character of LDHs, their temperature-induced transformations into metastable oxide materials and their ability to reconstruct the LDH state through the action of humidity or water lead to widespread their applications in many technological areas ranging from catalysis to polymer science or drug delivery. [178][179][180][181] They can be represented by the ideal formula…”

Section: Layered Double Hydroxidesmentioning

confidence: 99%

Combined solid-state NMR, FT-IR and computational studies on layered and porous materials

et al. 2018

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Understanding the structure-property relationship of solids is of utmost relevance for efficient chemical processes and technological applications in industries. This contribution reviews the concept of coupling three well-known characterization techniques (solid-state NMR, FT-IR and computational methods) for the study of solid state materials which possess 2D and 3D architectures and discusses the way it will benefit the scientific communities. It highlights the most fundamental and applied aspects of the proactive combined approach strategies to gather information at a molecular level. The integrated approach involving multiple spectroscopic and computational methods allows achieving an in-depth understanding of the surface, interfacial and confined space processes that are beneficial for the establishment of structure-property relationships. The role of ssNMR/FT-IR spectroscopic properties of probe molecules in monitoring the strength and distribution of catalytic active sites and their accessibility at the porous/layered surface is discussed. Both experimental and theoretical aspects will be considered by reporting relevant examples. This review also identifies and discusses the progress, challenges and future prospects in the field of synthesis and applications of layered and porous solids.

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Section: Layered Double Hydroxidesmentioning

confidence: 99%

Combined solid-state NMR, FT-IR and computational studies on layered and porous materials

et al. 2018

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“…Hence, to evaluate heterogeneous catalyst stability in a batch reactor, the spent catalyst should be recycled in a subsequent experiment. Yet, all too often, catalyst stability is concluded from repeated high yields that are either at full reactant conversion or at the thermodynamic equilibrium [8][9][10][11][12][13][14][15][16][17][18][19]. As a result, such experimental information does not provide any indication of the catalyst stability.…”

Section: Introductionmentioning

confidence: 99%

Catalyst Stability Assessment in a Lab-Scale Liquid-Solid (LS)² Plug-Flow Reactor

et al. 2019

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A packed-bed plug-flow reactor, denoted as the lab-scale liquid-solid (LS)² reactor, has been developed for the assessment of heterogeneous catalyst deactivation in liquid-phase reactions. The possibility to measure intrinsic kinetics was first verified with the model transesterification of ethyl acetate with methanol, catalyzed by the stable commercial resin Lewatit K2629, for which a turnover frequency (TOF) of 6.2 ± 0.4 × 10−3 s−1 was obtained. The absence of temperature and concentration gradients was verified with correlations and experimental tests. The potential for assessing the deactivation of a catalyst was demonstrated by a second intrinsic kinetics evaluation where a methylaminopropyl (MAP)-functionalized mesoporous silica catalyst was used for the aldol reaction of acetone with 4-nitrobenzaldehyde in different solvents. The cooperative MAP catalyst deactivated as a function of time on stream when using hexane as solvent. Yet, the monofunctional MAP catalyst exhibited stable activity for at least 4 h on stream, which resulted in a TOF of 1.2 ± 0.1 × 10−3 s−1. It did, however, deactivate with dry acetone or DMSO as solvent due to the formation of site-blocking species. This deactivation was mitigated by co-feeding 2 wt % of water to DMSO, resulting in stable catalyst activity.

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“…The nanostructured character of layered double hydroxides (LDHs), their temperature‐induced transformations into metastable oxide materials and their ability to reconstruct to the LDH state through the action of humidity or water lead to a range of applications within, for example, catalysis,1,2 gas sorption3,4 and drug delivery 5,6. The currently investigated materials belong to the hydrotalcite class of layered compounds, M II 1– x M III x (OH) 2 (A n – ) x / n · m H 2 O.…”

Section: Introductionmentioning

confidence: 99%

On the Thermal Stability and Structures of Layered Double Hydroxides Mg_1–xAl_x(OH)₂(NO₃)_x·mH₂O (0.18 ≤ x ≤ 0.38)

et al. 2015

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Nitrate-based layered double hydroxides, Mg 1-x Al x (OH) 2 -(NO 3 ) x ·mH 2 O, have been investigated to settle issues relating to stability towards humidity, dehydration and staging, nitrate group orientation, Al migration and crystal structure. Raman and IR spectroscopy together with modelling methods proved that flat-lying water and nitrate become tilted towards [001] at higher nitrate concentrations, accompanied by expansion along the c-axis. The distribution of the molecular tilts is greatest for x = 0.25, which explains the extraordinary broad diffraction peaks. The unit cell volume was modified for all samples when subjected to moist air, most strongly for x = 0.25. On heating, in situ synchrotron diffraction data showed continuous changes along the c-axis during [a]

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Recyclable hydrotalcite clay catalysed Baylis–Hillman reaction

Cited by 14 publications

References 14 publications

Combined solid-state NMR, FT-IR and computational studies on layered and porous materials

Combined solid-state NMR, FT-IR and computational studies on layered and porous materials

Catalyst Stability Assessment in a Lab-Scale Liquid-Solid (LS)² Plug-Flow Reactor

On the Thermal Stability and Structures of Layered Double Hydroxides Mg_1–xAl_x(OH)₂(NO₃)_x·mH₂O (0.18 ≤ x ≤ 0.38)

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Recyclable hydrotalcite clay catalysed Baylis–Hillman reaction

Cited by 14 publications

References 14 publications

Combined solid-state NMR, FT-IR and computational studies on layered and porous materials

Combined solid-state NMR, FT-IR and computational studies on layered and porous materials

Catalyst Stability Assessment in a Lab-Scale Liquid-Solid (LS)² Plug-Flow Reactor

On the Thermal Stability and Structures of Layered Double Hydroxides Mg1–xAlx(OH)2(NO3)x·mH2O (0.18 ≤ x ≤ 0.38)

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On the Thermal Stability and Structures of Layered Double Hydroxides Mg_1–xAl_x(OH)₂(NO₃)_x·mH₂O (0.18 ≤ x ≤ 0.38)