Manufacturing of Platinum- and Color-Free Organosilicon Products Using Heterogeneous Platinum Catalysts

Resource limitations, increased demand, and high cost of precious metals as well as desired low precious metal presence in organosilicon products have led to a focus on recovery of platinum from organosilicon hydrosilylation streams as a potentially important business strategy in the organosilicon industry. In this work, the heterogeneous catalysis process is demonstrated to be effective for platinum recovery and premier organosilicon product manufacturing. Because of the relatively lower catalytic activity of heterogeneous catalysts, higher reaction temperatures and longer reaction times are generally required to achieve hydrosilylation completion when using heterogeneous catalysts as compared to using homogeneous catalysts. However, by using heterogeneous catalysts, precious metals (e.g., platinum) can be easily separated from the processes to produce Pt- and color-free premier organosilicon products, and precious metals can be recovered for cost savings. In a continuous fixed-bed catalysis process with heterogeneous catalysts packed in the column, a very high space time yield of over 10 g product/(h.g catalyst) was demonstrated for manufacturing a model organosilicon product Siloxane-B, which indicates that very high product output could potentially be achieved in a much intensified continuous fixed-bed hydrosilylation reactor. The process is potentially more cost-effective than the conventional batchwise process for making such organosilicon products.