Covalently Supported Ionic Liquid Phases: An Advanced Class of Recyclable Catalytic Systems

Giacalone, Francesco; Gruttadauria, Michelangelo

doi:10.1002/cctc.201501086

Cited by 128 publications

(89 citation statements)

References 116 publications

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“…The second group comprises covalently linked IL phases, where the IL cation (or anion) is chemically bonded to the solid support. 36 The rst class of SILPs is relatively easy to prepare and these SILPs exhibit a straightforward mechanism of interactions of ILs with metal ions. 37 The main disadvantage of SILPs prepared by physisorption is the loss of the impregnated IL due to the solubility of the IL in the aqueous phase.…”

Section: Introductionmentioning

confidence: 99%

Recovery of scandium(iii) from diluted aqueous solutions by a supported ionic liquid phase (SILP)

2017

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The adsorption of scandium from diluted, acidic solutions by a supported ionic liquid phase (SILP) was investigated, as part of a process for recovery of scandium from bauxite residue (red mud). Both dry impregnation and covalent linking were studied for the SILP preparation. The SILP betainium sulfonyl(trifluoromethanesulfonylimide) poly(styrene-co-divinylbenzene) [Hbet-STFSI-PS-DVB] was prepared by covalent linking of the ionic liquid to the resin and this resulted in an adsorbent suitable for scandium recovery. For a chloride feed solution, the effects of pH, contact time, adsorption capacity, desorption, reusability of adsorbent and the influence of Fe(III), Al(III) and Ca(II) on the Sc(III) adsorption were studied. The adsorption of Sc(III) from nitrate and sulfate feed solution under optimal conditions was studied as well. The adsorption kinetics followed a pseudo-second order kinetic model. Equilibrium studies at room temperature showed that the experimental data could be well fitted by the Langmuir isotherm model. The stripping of Sc(III) from the loaded SILP was achieved with 1 M sulfuric acid. The SILP was stable and could be reused for seven adsorption/desorption cycles without significant losses in its adsorption efficiency for Sc(III). IntroductionScandium belongs to the group of rare-earth elements (REEs) and nds applications in aluminum alloys, halide lamps and fuel cells.1 However, it is an expensive metal with small global production volumes. Although scandium is relatively abundant in the Earth's crust (22 ppm), there are few scandium minerals and it rarely occurs in rich ore deposits. It is mainly recovered as by-product from the production of other metals (REEs, U, Ti, W, Al, Ni, Ta and Nb).2-4 Bauxite residue (red mud), the waste industrial product of the Bayer process for alumina production from bauxite ore, can contain up to 130 ppm of scandium and it is potentially a valuable scandium resource.5,6 Scandium can partially be recovered from bauxite residue by acid leaching. Typically, in this way many metal impurities go into the leachate as well and in concentrations much higher than that of scandium. 1,7,8 Liquid-liquid extraction is used for the recovery of Sc(III), 9 but it requires much higher initial concentrations of Sc(III) than the ones that can be found in the pregnant leach solutions.1 Nevertheless, for recovery of low concentrations of Sc(III) its enrichment with a selective adsorbent in high capacity ion exchange columns could be an efficient technique. Much of the research work on Sc(III) recovery by adsorption and extraction has been performed with resins, View Article OnlineView Journal | View Issue components can contaminate the aqueous effluents. 37 In the second class of SILPs there is no discrete IL phase in the structure of the solid support. Instead, the IL can be considered as a covalently anchored ligand. Covalent linking ensures that the IL will not be leached from the support. 32,40The objective of this work is to develop a stable SILP for the adsorption of Sc(III...

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Section: Introductionmentioning

confidence: 99%

Recovery of scandium(iii) from diluted aqueous solutions by a supported ionic liquid phase (SILP)

2017

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“…The catalytic activity of both SCILL and SILP catalysts in the hydrogenation of benzene was mainly investigated by Ru‐, Rh‐ and Pt‐based catalysts (Table entries 9, 10, 11, 13, 15, 21, 26, 27, and 28) and is apparently dependent on the size of metal NPs as well as on the hydrophobicity of the IL, although the available data are limited ,,,,. For example, Ru NPs are mainly generated in situ from organometallic precursors in water soluble ILs such as BMIm.BF 4 (entries 10, 11 and 13, Table ) and TMG.TFA (entry 26, Table ).…”

Section: Hydrogenation Of Benzene and Alkyl Benzenesmentioning

confidence: 99%

Arene Hydrogenation by Metal Nanoparticles in Ionic Liquids

Chacón

Dupont

2018

ChemCatChem

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Ionic liquids (ILs) have been extensively explored in controlling the selectivity and stability of metal nanoparticles and/or classical heterogeneous catalysts for the hydrogenation of aromatics. ILs provide a protective layer to metal surface catalysts and a physical barrier controlling the access of substrates/intermediates/products on the nanoconfined catalysts, acting as an electronic and geometrical modifier of the catalytic active sites. As a result, this allows the stability and electronic/geometrical properties of the catalyst to be modulated. The IL layers also allow nano‐environments to be designed for encapsulation and to change the kinetic/thermodynamic of the process compared to those reactions performed in classical heterogeneous catalysis. We will focus on the physical, geometric and electronic effects imposed by the IL on metal nanoparticles and classical heterogeneous catalysts on activity and selectivity in the hydrogenation of arenes, in particular benzene.

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“…In 2014, a series of multilayered covalently-supported ionic liquid phase (mlc-SILP) materials 18, 19a-b, 20a-b, 21a-b were synthesised by grafting different bis-vinylimidazolium salts on thiolfunctionalised silica (Scheme 9) [17]. Covalently-supported imidazolium salts represent an interesting class of recyclable catalysts with excellent stability and durability [18,19]. Bis-imidazolium salts with different organic linkers (ethane, butane, octane, p-xylene) between the two imidazolium units and two types of halides as counterions (X = Br or I) were used.…”

Section: Synthesis Of Cyclic Carbonatesmentioning

confidence: 99%

Advances in Organic and Organic-Inorganic Hybrid Polymeric Supports for Catalytic Applications

2016

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Abstract:In this review, the most recent advances (2014)(2015)(2016) on the synthesis of new polymer-supported catalysts are reported, focusing the attention on the synthetic strategies developed for their preparation. The polymer-supported catalysts examined will be organic-based polymers and organic-inorganic hybrids and will include, among others, polystyrenes, poly-ionic liquids, chiral ionic polymers, dendrimers, carbon nanotubes, as well as silica and halloysite-based catalysts. Selected examples will show the synthesis and application in the field of organocatalysis and metal-based catalysis both for non-asymmetric and asymmetric transformations.

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Covalently Supported Ionic Liquid Phases: An Advanced Class of Recyclable Catalytic Systems

Cited by 128 publications

References 116 publications

Recovery of scandium(iii) from diluted aqueous solutions by a supported ionic liquid phase (SILP)

Recovery of scandium(iii) from diluted aqueous solutions by a supported ionic liquid phase (SILP)

Arene Hydrogenation by Metal Nanoparticles in Ionic Liquids

Advances in Organic and Organic-Inorganic Hybrid Polymeric Supports for Catalytic Applications

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