Microcharacterization of New Platinum Catalysts for Hydrosilylation Reactions

Organofunctional silanes are the key intermediates for production of silicon polymeric chemicals. Traditionally, platinum catalysts on carbon support materials have been used for these hydrosilylation reactions. The efficiency of the current commercial Pt/C catalyst is not very satisfactory, so a catalyst of platinum on aluminum oxide support was developed to accelerate the reactions. The Pt/Al2O3catalyst greatly increases both reaction and conversion rates. However, the acidic nature of the supporting material is sometimes undesirable. Recently, a new class of platinum-copper bimetallic catalysts has been developed at Dow Corning, using co-deposition techniques with platinum chloride and copper chloride precursors. The bimetallic catalysts have also demonstrated significantly improved on hydrosilylation reaction efficiency and rates. The activity, selectivity, and stability of the catalysts are related to their structural properties, including catalyst particle size, size distribution, and particle composition. The knowledge of catalyst structures are, therefore, very important for understanding the performance of the catalysts and for optimizing production processes.