The activity of Pt/SiO 2 catalysts obtained by the sol-gel method in the hydrosilylation of 1-alkynes

Heterogeneous platinum catalysts (Pt/SiO 2 ) obtained by the sol-gel process at pH 3 and 9 have been used in the hydrosilylation reaction of 1-alkynes using various silanes. Once the catalysts were activated they were used in the hydrosilylation of 1-alkynes after a short induction period. The product distribution was quite similar in either case but important differences in catalytic activity and turnover reactions were observed. The catalyst obtained in the basic medium after each reaction lost its catalytic activity, so further activation was needed. To understand this behavior, the catalysts were characterized by 29 Si CPMAS NMR, FT IR, and BET surface area measurements. The 29 Si CPMAS NMR studies showed the presence of terminal and bridged hydroxyl groups in the Pt/SiO 2 catalyst at pH = 9. Similar results were observed by FT IR analysis because of the catalysts' synthetic conditions.