Modified zirconia solid acid catalysts for organic synthesis and transformations
IR@IICT: CSIR-Indian Institute of Chemical Technology, Hyderabad
View Archive Info| Field | Value | |
| Creator |
Reddy, B.M
Sreekanth, P.M Reddy, V.R |
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| Date |
2009-01-21T09:27:55Z
2009-01-21T09:27:55Z 2005 |
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| Identifier |
Journal of Molecular Catalysis A: Chemical, Vol. 225, 71–78p
1381-1169 http://hdl.handle.net/123456789/856 |
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| Description |
A series of sulfate, molybdate and tungstate promoted ZrO2 catalysts were prepared by wet impregnation method. To incorporate these promoters to Zr(OH)4, sulfuric acid, ammonium heptamolybdate, and ammonium metatungstate were used as precursors, respectively. Further, a Pt promoted Mo-ZrO2 catalyst was also prepared separately by impregnating with hexachloroplatinic acid. The surface and bulk properties of various promoted ZrO2 catalysts were investigated by means of X-ray powder diffraction, BET surface area, ammonia-TPD, and Raman spectroscopy techniques. The unpromoted ZrO2 when calcined at 873 K exists in the crystalline form with monoclinic phase dominating over the tetragonal phase. Incorporation of various promoters into Zr(OH)4 shows a strong influence on the bulk and the surface properties. Addition of promoters enhanced the tetragonal zirconia phase and the surface acidity. In the case of Pt/Mo-ZrO2 catalyst, a complete tetragonal ZrO2 phase is observed. The ammonia-TPD results indicate that the impregnated sulfate ions show a strong influence on the acidity of ZrO2, which is followed by molybdate. The prepared catalysts were evaluated for various organic synthesis and transformation reactions in the liquid phase. All catalysts exhibit good catalytic activity for synthesis of diphenylureas, coumarines and 1,5-benzodiazepines, acylation of alcohols, phenols and amines, and protection of carbonyl compounds. In particular, the sulfate and molybdate promoted catalysts exhibited excellent catalytic activity.
IICT |
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| Language |
en
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| Publisher |
Elsevier
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| Subject |
Zirconium oxide
Solid superacid Sulfate Molybdate Tungstate Diphenylureas Coumarins 1,5-Benzodiazepines Tetrahydropyranylation Acylation |
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| Title |
Modified zirconia solid acid catalysts for organic synthesis and transformations
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| Type |
Article
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