Catalyst recycling in monophasic Pt-catalyzed hydrosilylation reactions using ionic liquids

The technical relevant Pt-catalyzed hydrosilylation of allyl chloride with trichlorosilane was investigated in a monophasic reaction system containing an ionic liquid (IL) additive. ILs screening allowed us to identify the liquid 1-decyl-3-methylimidazolium bis(trifloromethanesulfonyl)amide ([DMIM][NTf2]) as the best additive for such process. This IL combined complete miscibility with reactants as long as chemical and thermal robustness. After the reaction, the hydrosilylation product (3-chloropropyl)trichlorosilane was distilled off and the residual IL/catalyst solution could be reused. In such a way, a final TON of 14,200 was achieved over 10 reaction/distillation cycles without any loss of catalytic activity. The ability of [DMIM][NTf2] to prevent catalyst decomposition was deeper investigated and it was found that even with a Pt loading as high as 9500 ppm, the IL acted as protective/stabilizing agent for the catalyst during the thermally stressing product distillation.

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► Technically challenging hydrosilylation with trichlorosilane with ionic liquids.
► Ionic liquid tailoring to get homogeneous monophasic system.
► Catalyst full recyclability up to 10 times.
► Promising industrial implementation.