Hydrosilation in supercritical CO2: Synthesis of fluorinated polysiloxanes

Hydrosilation of poly(methylhydrosiloxane) with a fluorinated olefin in sup ercritical CO2 (scCO(2)) using Karstedt's Pt catalyst has been successfully demonstrated; results were compared with those obtained in a subcritical c onventional solvent, i.e. toluene. Rates of hydrosilation were found to be dependent on solvent, reactant concentration, and reaction temperature. Lev els of hydrosilation were 40-50%, depending on reaction conditions. Gel for mation, which was not observed under any conditions in subcritical toluene, occurred in all reactions done in scCO(2) and accounted for up to 20 wt.-% of the final product mix.