Supported heteropolyadds

Blasco T, Corma A, Martinez A, Maitinez-Escolano P (1998) Supported heteropolyadd (HPW) catalysts for the continuous alkylation of isobutane with 2-butene the benefit of using MCM-41 with larger pore diameters. J Catal 177 306-313... 

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... 

The effect of H3PW12O40 and P(OPh)3 on the activity and selectivity of MCM-41-supported rhodium(I) and rhodium(III) catalysts was investigated in the hydroformylation reaction of 1-octene and styrene. The heteropolyadd-impregnated catalyst was found to enhance the catalytic activity [90]. The addition of P(OPh)3 increased the selectivity of the reaction toward the branched product [91]. 

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