Acetalization of carbonyl compounds catalyzed by acidic ionic liquid immobilized on silica gel

Miao, Jinmei; Wan, Hui; Shao, Yanbing; Guan, Guofeng; Xu, Bin

doi:10.1016/j.molcata.2011.08.005

Cited by 119 publications

(81 citation statements)

References 28 publications

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“…However, when the reaction conducted in the presence of imidazolium hydrogensulfate ([Hmim]HSO 4 ) and methyl imidazolium hydrogen chloride ([Hmim]Cl) as two non-supported ILs the desired product was obtained in 40 and 30 % yields, respectively (Table 1, entries 4, 5). (Table 1, entries [6][7][8]. This could be because of insolubility of the reactants in H 2 O and the low boiling points of MeOH and EtOH.…”

Section: Synthesis Of Triarylpyridines and Diindeno Pyridines Catalyzmentioning

confidence: 99%

“…High viscosity limits their mass transfer during catalytic reactions and makes their handling difficult. Moreover, use of relatively large amounts of ionic liquids, and their homogeneity, cause environmental problems [4][5][6]. These problems and the priority of the chemical industry to use heterogeneous catalysts has resulted in immobilization of ILs on to solid supports [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

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The synthesis of polysubstituted pyridines using nano Fe3O4 supported hydrogensulfate ionic liquid

2015

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Reaction of 1-methylimidazole with 3-(trimethoxysilyl)propyl chloride resulted in formation of 1-methyl-3-(trimethoxysilyl)propyl imidazolium chloride ([pmim]Cl). Anchoring of the ionic liquid on to silica-coated magnetic Fe 3 O 4 particles afforded the corresponding supported ionic liquid MNP-[pmim]Cl. Exchanging the Cl -anion by treatment with H 2 SO 4 gave the Brønsted ionic liquid MNP-[pmim]HSO 4 . FT-IR, XRD, SEM, TEM, TG/DTG, VSM, and CHN analysis were used to characterize the supported ionic liquid. The results indicated the catalyst was a nanostructure. The catalytic activity of the supported ionic liquid was examined in the synthesis of the polysubstituted pyridines by reaction of aromatic aldehydes, and acetophenones or indan-1-one with ammonium acetate under solvent-free conditions. The catalyst could be easily recovered, by applying an external magnetic field, and reused at least six runs without deterioration of its catalytic activity.

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Section: Synthesis Of Triarylpyridines and Diindeno Pyridines Catalyzmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The synthesis of polysubstituted pyridines using nano Fe3O4 supported hydrogensulfate ionic liquid

2015

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“…To solve those problems, a variety of solid acidic catalysts, which were prepared by immobilization of acidic catalysts on various inorganic or organic supporters, have been investigated [11][12][13][14][15][16][17][18][19][20]. Furthermore, many acid or Lewis acid-functionalized ionic liquids were used for acetalization or ketalization [21][22][23][24]. However, such catalysts required complex synthetic routes and long technological processing.…”

Section: Introductionmentioning

confidence: 99%

Highly Efficient Acetalization and Ketalization Catalyzed by Cobaloxime under Solvent-Free Condition

et al. 2018

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An efficient catalytic system was developed for the acetalization and ketalization of carbonyl compounds with polyhydric alcohols under mild solvent-free conditions. In the presence of 0.1 mol% CoCl 2 and 0.2 mol% dimethylglyoxime at 70 • C under 5 KPa pressure for 1 h, 95.3% conversion of cyclohexanone and 100% selectivity of the corresponding cyclic ketal could be obtained, where TOF reached as high as 953 h −1 . It is proposed that the in situ generated planartetracoordinate cobaloxime played the key role in the catalytic cycle and was responsible for the excellent catalytic performance.

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“…A modified tethering method produced a catalyst that performed the acetalization of aldehydes and alcohols and could recycled 10 times with minimal loss of activity. 30 Funabiki et al 31 prepared a solid acid catalyst by the adsorption of the acidic ionic liquid 1,3-bis(3-sulfopropyl)-1H-imidazol-3-ium trifluoromethanesulfonate onto a commercial silica gel. The resulting SILP material could be reused 10 times for the esterification of bromoacetic acid with benzyl alcohol.…”

mentioning

confidence: 99%

A Recyclable Acidic Ionic Liquid Gel Catalyst for Dehydration: Comparison with an Analogous SILP Catalyst

Wang

Ulrich

Donnelly

et al. 2015

ACS Sustainable Chem. Eng.

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An acid-functionalized ionic liquid was entrapped within a silica gel to yield a recyclable liquid phase catalyst for the dehydration of rac-1-phenyl ethanol. Hot filtration tests showed that the activity was within the gel. Comparison with an analogous SILP system revealed fundamental differences in the properties and behavior of the materials.The discovery of facile ionic-liquid silica gel formation, 1,2 enabled the introduction of the first ionic liquid mediated sol-gel methods for the preparation of solid catalysts. [3][4][5] There followed a period of relatively few publications, during which ionic liquid gels were seldom investigated as catalysts. Currently, in parallel with the development of new classes of ionic liquid, and an increase in interest in softmatter, the area of ionic liquid gel catalysts has come back into focus, and new methods are emerging. This catalyst preparation methodology involves the entrapment of an ionic liquid within an inorganic oxide matrix by a gel method. At the same time a catalyst is co-entrapped, 3,[5][6][7] or, alternatively the catalytic center can be associated with the ionic liquid. 4 The worked-up material is then used as a heterogeneous catalyst. Materials consisting of an ionic liquid within a porous oxide are often referred to as ionogels. 8 These catalysts are a sub-set of the sol-gel prepared entrapped catalysts pioneered by Blum and Avnir. 9,10 In contrast to the gel-based catalysts, the related SILP catalysts, in which a heterogeneous catalyst is prepared by layering an ionic liquid on a pre-existing oxide matrix, have elicited an explosion of interest in the last ten years. Several reviews and concept articles have been published covering the method. [11][12][13][14][15][16][17] Exemplars have been demonstrated in the gaseous phase, 18 and using supercritical fluids, [19][20][21] and the application of SILP technology is at an advanced stage. The simplicity of the system enables a wide variety of matrices, ionic liquids and dopants to be screened easily. In liquid phase reactions the ease of addition and removal of the ionic liquid is potentially detrimental, and leaching can be facile.The development of supported nanoparticles catalysts by ionic-liquid assisted gel methods 3 has been recently developed further by Han and co-workers. 22 Catalysts with hierarchical pores were achievable by employing a metal salt (e.g. CaCl 2 ) initiated gelation. Doping with gold afforded a catalyst for esterification, and ruthenium catalyzed hydrogenation.The introduction of functionalized ionic liquids that are 'task specific' 23-26 opens up many new possibilities for the application of ionic liquids to liquid phase reactions, not least the incorporation of Brønsted-Lowry Acidic/Basic sites. Acid functionalized ionic liquids have been demonstrated as robust catalysts for continuous esterification in a miniplant. 27 In order to improve separation and prevent corrosion caused by liquid phase acids, it would be fortuitous to develop a heterogenised system. The combinat...

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Acetalization of carbonyl compounds catalyzed by acidic ionic liquid immobilized on silica gel

Cited by 119 publications

References 28 publications

The synthesis of polysubstituted pyridines using nano Fe3O4 supported hydrogensulfate ionic liquid

The synthesis of polysubstituted pyridines using nano Fe3O4 supported hydrogensulfate ionic liquid

Highly Efficient Acetalization and Ketalization Catalyzed by Cobaloxime under Solvent-Free Condition

A Recyclable Acidic Ionic Liquid Gel Catalyst for Dehydration: Comparison with an Analogous SILP Catalyst

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