Catalytic behavior of Li-Al-LDH prepared via mechanochemical and co-precipitation routes for cyanoethylation reaction

Pavel, Octavian Dumitru; Stamate, Alexandra-Elisabeta; Bacalum, Elena; Cojocaru, Bogdan; Zăvoianu, Rodica; Pârvulescu, Vasile I.

doi:10.1016/j.cattod.2020.06.019

Cited by 22 publications

(7 citation statements)

References 50 publications

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“…From 210 to 570℃, the weight loss is 40.4%, which is the main loss range for ES-LDH. According to the DTG curve, the hydroxyl decomposition dehydration reaction starts at 200-300℃, with the highest weight loss at 400-450℃, which corresponds to the decomposition and release of interlayer SDBS and EDTA, collapse the layered structure and formation of LDO [35,36]. Therefore, these TG-DTG curves are consistent with the typical thermogravimetric curves of LDH.…”

Section: Characterization Of Es-ldhsupporting

confidence: 74%

Novel Layered Double Hydroxides@Carboxymethyl Cellulose Composite Aerogel Towards Co(II) Absorption

Wang

Long

Wei

et al. 2022

Preprint

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Cobalt (Co) ion is a common heavy metal ion and the main metal ion in nuclear wastewater. However, the study on the absorption for Co(II) is not sufficient. Herein, a novel ES-layered double hydroxide (LDH) is prepared by intercalated ethylenediaminetetraacetic acid disodium salt (EDTA) and sodium dodecylbenzene sulfonate (SDBS) in a magnesium, iron pristine LDH, which is subsequently used for ES-LDH@carboxymethyl cellulose (CMC) composite aerogel. The results of Fourier transform infrared spectroscopy, X-ray diffraction spectra and thermogravimetric analysis shows successfully preparation of intercalated LDH. The pore morphology, specific surface area and pore size distribution of the composite aerogels are characterized by scanning electron microscope and Nitrogen-BET curves. The significantly improved adsorption capacity, adsorption kinetics and isotherms the absorbents on Co(II) are systematically revealed. This study thus provides an important understanding and path for dealing with the threat of Co(II).

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Section: Characterization Of Es-ldhsupporting

confidence: 74%

Novel Layered Double Hydroxides@Carboxymethyl Cellulose Composite Aerogel Towards Co(II) Absorption

Wang

Long

Wei

et al. 2022

Preprint

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“…Besides these, the need for large amounts of energy or water (in the washing step) or the need for specific glassware for the preparation are other disadvantages that these inorganic alkalis generate. A new approach that removes all these drawbacks considers the use of organic alkalis for LDH synthesis [27][28][29]. However, the replacement of inorganic alkalis with organic ones could be somehow restrictive due to their price, inadequate solubility in water, and tendency to decompose during preparation or storage over time, as well as the possible presence of impurities in their composition, etc.…”

Section: Introductionmentioning

confidence: 99%

An Advanced Approach for MgZnAl-LDH Catalysts Synthesis Used in Claisen-Schmidt Condensation

et al. 2022

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Using organic-base tetramethylammonium hydroxide (TMAH) is a viable, cheap, and fast option for the synthesis of MgZnAl-LDH-type materials by both co-precipitation and mechano-chemical methods. TMAH presents several advantages, such as the smaller quantity of water required in the washing step compared to the use of inorganic alkalis, the prevention of LDH contamination with alkali cations, and its action as a template molecule in texture tailoring. It also has disadvantages, such as its presence in small quantities in the resulting layered materials. Regardless of the use of organic/inorganic bases and co-precipitation/mechano-chemical methods, zincite stable phase was found in all the synthesized solids. The basicity of catalysts followed the trend: mixed oxides > reconstructed > parent LDH. The memory effect of LDH was supported only by the presence of Mg and Al cations, while Zn remained as a zincite stable phase. The catalytic activities for Claisen–Schmidt condensation of benzaldehyde with cyclohexanone provided values higher than 90% after 2 h, with a total selectivity toward 2,6-dibenzylidenecyclohexanone, while self-condensation of cyclohexanone yielded no more than 7.29% after 5 h. These behaviors depended on catalyst basicity as well as on the planar rigidity of the compound.

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“…Synthesis of Mg/Al/Y mixed oxide : Mg 0.75 Al 0.125 Y 0.125 ‐LDH precursor was prepared by a mechano‐chemical method [32] using established amounts of Mg(NO 3 ) 2 ⋅ 6H 2 O, Al(NO 3 ) 3 ⋅ 9H 2 O and Y(NO 3 ) 3 ⋅ 6H 2 O (at a molar ratio Mg/Al+Y=3) dispersed in 100 mL tetra‐methyl ammonium hydroxide (25 wt. % in H 2 O).…”

Section: Methodsmentioning

confidence: 99%

Valmet Chiral Schiff‐Base Ligands And Their Copper(II) Complexes as Organo, Homogeneous and Heterogeneous Catalysts for Henry, Cyanosilylation and Aldol Coupling Reactions

et al. 2021

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Cyanosilylation, aldol coupling and asymmetric Henry reactions were carried out with L‐ and D‐valmet ligands in different configurations: i) coordinated to sodium ions, as organocatalysts, with week base properties, ii) complexes with copper(II), as homogeneous catalysts, and iii) immobilized copper(II) complexes onto graphene oxide (GO) as heterogeneous catalysts. For the reaction of benzaldehyde and nitromethane in water these afforded an asymmetric Henry reaction, with a spectacular increase of the conversion and ee (92.5 and 95.8 %, respectively) after the deposition on GO. Ligand complexed copper was also effective for cyanosilylation and Aldol coupling reaction.

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Catalytic behavior of Li-Al-LDH prepared via mechanochemical and co-precipitation routes for cyanoethylation reaction

Cited by 22 publications

References 50 publications

Novel Layered Double Hydroxides@Carboxymethyl Cellulose Composite Aerogel Towards Co(II) Absorption

Novel Layered Double Hydroxides@Carboxymethyl Cellulose Composite Aerogel Towards Co(II) Absorption

An Advanced Approach for MgZnAl-LDH Catalysts Synthesis Used in Claisen-Schmidt Condensation

Valmet Chiral Schiff‐Base Ligands And Their Copper(II) Complexes as Organo, Homogeneous and Heterogeneous Catalysts for Henry, Cyanosilylation and Aldol Coupling Reactions

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