Platinum nanoparticles onto pegylated poly(lactic acid) stereocomplex for highly selective hydrogenation of aromatic nitrocompounds to anilines

•Pegylated poly(lactic acid) stereocomplex (L) was stable in methanol at room temperature.•Pt nanoparticles on L hydrogenated aromatic nitrocompounds to anilines.•Covalently attached polyethyleneglycol contributed to catalytic activity.•The high chemoselectivity for anilines was Pt nanoparticles' size-dependent.

A stereocomplexed poly(lactic acid)-polyethyleneglycol copolymer was synthesized and successfully used as recyclable support for Pt nanoparticles, generated by the metal vapor synthesis technique. The confinement of the Pt nanoparticles were determined by thermal analysis. Hydrogenation reactions of chlorinated aromatic nitro compounds, containing other reducible functional groups, to the corresponding anilines occurred with the latter supported Pt nanoparticles in MeOH under very mild reaction conditions (i.e. 30 °C, p(H2) = 5.0 bar). The covalently attached polyethyleneglycol polymer significantly increased the catalytic activity of the supported Pt nanoparticles compared to an analogous catalytic system which did not contain polyethyleneglycol but the same sized Pt nanoparticles.

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