Catalysis Science & Technology Blog

Compared to homogeneous catalysts, heterogeneous catalysts used in hydrosilylation reactions are quite rare. In this HOT article, the catalytic activity and recyclability of PtO₂ is examined for the hydrosilylation of n-octene with heptamethyltrisiloxane.

Compared to the usual homogeneous catalysts PtO₂ dissolves only to a small degree after reaction with silane. The un-reacted solid catalyst is then easily separated from the reaction mixture by simple decantation or filtration and so can be used for subsequent runs. The observation of an induction period in every cycle indicates that the active species is formed in situ before the reaction can take place and new material has to dissolve for each run.

The active species is formed by reduction of PtO₂ with the silane and is soluble in the reaction mixture. The solubility behavior together with the high activity allows a ‘‘self-dosing’’ of the catalyst—leading to little waste of precious metal in contrast to other ‘‘homogeneous’’ (i.e. better soluble) Pt-based catalysts making it potentially useful for industrial applications.

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PtO₂ as a “self-dosing” hydrosilylation catalyst
Sophie Putzien, Eckhart Louis, Oskar Nuyken and Fritz E. Kühn
Catal. Sci. Technol., 2012, Advance Article
DOI: 10.1039/C2CY00367H