Clay-supported heteropolyacid

Reaction conditions Neat condition, room temperature, ultrasotmd irradiation Synthetic strategy One-pot multi-component reaction Cataiyst Clay-supported heteropolyacid (HPA)... 

Other metals can be similarly immobilised. Silica- and clay-supported rhodium complexes, for example, are effective hydrogenation catalysts.160,161 An interesting variant on this involves a heteropolyacid to assist the metal-support binding. The heteropolyadd, such as phosphotungstic add, is attached to the support (e.g. montmorillonite) by the indpient wetting technique. The solid material is then treated with a solution of the homogeneous catalyst such as Rh(DiPamp).162... 

In catalysis, oxides with well defined acidic and basic properties are used in different forms that have found application in numerous catalytic applications in the gas-solid and liquid-solid heterogeneous catalysis [3, 46, 47], Among the most used oxide materials in catalysis, we And (i) bulk oxides (one component metal oxides) (ii) doped and moditied oxides (iii) supported metal oxides (dispersed active oxide component onto a support oxide component) (iv) bulk and supported binary metal oxides to quaternary metal oxides (mixed oxide compositions) (v) complex oxides (e.g., spinels, perovskites, hexa-aluminates, bulk and supported hydrotalcites, pillared clays, bulk and supported heteropolyacids, layered silicas, etc.). 

Complex oxides comprise a large variety of structures which gained importance in the catalysis field due to their acidity or basicity properties (e.g., spinels, perovskites, hexa-aluminates, bulk and supported hydrotalcites, pillared clays, bulk and supported heteropolyacids, etc.). 

Yadav GD, Bhagat RD (2004) Synthesis of methyl phenyl glyoxylate via clean oxidation of methyl mandelate over a nanocatalyst based on heteropolyacid supported on clay. Org Process Res Dev 8 879... 

A number of new acetonation conditions have been examined. Use of acetone in the presence of K 10 clay gave the 2,3-0-isopropylidene derivatives of d-ribofuranose and L-rhamnopyranose and the expected di-O-isopropylidene derivatives of D-xylose, D-glucose, D-galactose and D-mannose in excellent yields. Good to excellent yields of the expected acetonides of methyl a-D-manno-, a-D-gluco-, and a-D-galacto-pyranoside as well as of D-mannose have been obtained with acetone and titanium(IV) chloride supported on modified silica gel. H3PM012O40 was the most active of 18 heteropolyacids examined as catalysts in the acetonation of L-sorbose. ... 

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