Heterogeneous Bismuth Nanocatalyst for Selective Hydrogenation of Alkenes

Abstract

Bismuth is widely recognized for its remarkable safety, with numerous examples showcasing its low toxicity. Considering this, we introduce a heterogeneous nanocatalyst (Bi-PN/MgO) with excellent efficiency, reusability, and stability, specifically designed for the chemoselective hydrogenation of C═C bonds in diverse olefins. Catalyst synthesis involves a straightforward impregnation technique followed by pyrolysis at 700 °C under a nitrogen atmosphere. The physicochemical properties of catalysts were determined through thorough characterization techniques including powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HR-TEM), N₂-adsorption–desorption, H₂-TPR, NH₃-TPD, inductively coupled plasma optical emission spectroscopy (ICP-OES), and thermogravimetric analysis. The versatility of Bi-PN/MgO is demonstrated across a diverse range of substrates for double bond reduction, covering over 29 examples, including challenging substrates with other reducible functional groups. The catalyst’s efficacy was further validated through the hydrogenation of dicyclopentadiene, citral, eugenol, and isoeugenol into their valuable hydrogenated products on a ∼1 g scale, with yields reaching up to 98%. The scalability of the process was also exhibited through a ∼1 g scale synthesis of zingerone achieved by selectively reducing the double bond in dehydrozingerone derived from lignin. The analysis of the spent catalyst confirmed its stability and reusability for up to four cycles, demonstrating no noticeable loss of activity or selectivity.