Modified zirconia solid acid catalysts for organic synthesis and transformations

Reddy, Benjaram M.; Sreekanth, Pavani M.; Reddy, V. Krishna

doi:10.1016/j.molcata.2004.09.003

Cited by 102 publications

(52 citation statements)

References 54 publications

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“…However, the need for an environmentally benign and facile protocol still exists. Among various solid acid catalysts, the sulfate-ion promoted zirconia received much attention recently due to its high thermal stability, large specific surface area, easy recovery and reusability, and ability to perform organic reactions at much lower temperatures [23][24][25][26][27][28]. Also in recent times, inorganic solid acid catalyzed organic reactions are gaining much attention due to the proven advantage of heterogeneous catalysts such as simplified product isolation, mild reaction conditions, high selectivity, ease in recovery and reuse of the catalysts, and reduction in the generation of wasteful products [29][30][31].…”

Section: Introductionmentioning

confidence: 99%

An Efficient Protocol for Aza-Michael Addition Reactions Under Solvent-Free Condition Employing Sulfated Zirconia Catalyst

2008

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The aza-Michael addition reactions of amines with a,b-unsaturated carbonyl compounds were efficiently carried out at room temperature under solvent-free condition employing sulfated zirconia as a reusable heterogeneous catalyst. The desired products were formed in short reaction times and in high yields. The bulk and surface properties of the synthesized catalyst was examined by X-ray powder diffraction, BET surface area, temperature programmed desorption of ammonia, scanning electron microscopy and thermogravimetric techniques. Characterization results reveal the super acidic nature of the catalyst.

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Section: Introductionmentioning

confidence: 99%

An Efficient Protocol for Aza-Michael Addition Reactions Under Solvent-Free Condition Employing Sulfated Zirconia Catalyst

2008

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“…Among various solid acid catalysts that were reported, sulfated zirconia (SZ) gained much attention due to its high activity and efficiency to catalyze many reactions even at low temperatures [10][11][12][13][14][15][16]. However, the SZ catalyst gets deactivated rapidly at high temperatures and in reducing atmosphere by forming SO x and H 2 S, respectively.…”

Section: Introductionmentioning

confidence: 99%

An Efficient and Ecofriendly WOx–ZrO2 Solid Acid Catalyst for Classical Mannich Reaction

2008

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An ecofriendly WO x -ZrO 2 solid acid catalyst has been employed for the synthesis of b-amino ketones by a three-component Mannich reaction in the liquid phase under solvent-free conditions at ambient temperature. To make the WO x -ZrO 2 catalyst, WO x from ammonium metatungstate was incorporated into the hydrous zirconia and calcined at 923 K. The incorporated promoter showed a strong influence on the surface and bulk properties of the zirconia. Surface and bulk properties of the catalyst were investigated by means of X-ray powder diffraction, temperature programmed desorption of ammonia, Raman spectroscopy, scanning electron microscopy, and BET surface area methods. Characterization studies reveal that the WO x -ZrO 2 catalyst exhibits strong solid acidity. The catalytic activity results suggest that the methodology adopted offers significant improvements for the synthesis of b-amino ketones with regard to yield of products, simplicity in the operation, and green aspects by avoiding toxic conventional catalysts and solvents.

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“…Mixed metal oxides, with two or more components, are of significant scientific and commercial interest [3][4][5]. In fact these systems exhibit enhanced chemical-physical properties (higher surface area, higher pore volume, superior thermal and chemical stability) and higher catalytic activity than their individual components [6,7].…”

Section: Introductionmentioning

confidence: 99%

Aerogel and xerogel WO3/ZrO2 samples for fine chemicals production

Signoretto

Ghedini

Menegazzo

et al. 2013

Microporous and Mesoporous Materials

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a b s t r a c t WO 3 /ZrO 2 systems were prepared by sol-gel technique using different procedures for the solvent extraction: evaporation in vacuum at room temperature (xerogel) and extraction in supercritical conditions (aerogel). Two reactions of industrial interest were investigated under mild conditions: (i) acylation of veratrole with acetic anhydride; (ii) acylation of anisole with benzoic anhydride. Several techniques were employed in order to study the influence of the synthetic parameters on texture and catalytic activity: N 2 physisorption, Fourier transformed-infrared spectroscopy, X-ray photoelectron spectroscopy, temperature programmed reduction and temperature programmed oxidation analyses. The solvent extraction strongly influences metal reducibility, surface area, pores organisation, W/Zr surface density and metallic interactions. The aerogel sample shows the best catalytic results for both conversion and yield. The supercritical extraction plays a central role especially in the recycling: by proper air activation, the aerogel sample attains the complete restoration of the catalytic activity even after three runs.

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Modified zirconia solid acid catalysts for organic synthesis and transformations

Cited by 102 publications

References 54 publications

An Efficient Protocol for Aza-Michael Addition Reactions Under Solvent-Free Condition Employing Sulfated Zirconia Catalyst

An Efficient Protocol for Aza-Michael Addition Reactions Under Solvent-Free Condition Employing Sulfated Zirconia Catalyst

An Efficient and Ecofriendly WOx–ZrO2 Solid Acid Catalyst for Classical Mannich Reaction

Aerogel and xerogel WO3/ZrO2 samples for fine chemicals production

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