MBC-Guanidine-Ni: A Stable Magnetic Biochar-based Nanocatalyst for Optimization and Control of a Coupling in the Propargylamine Synthesis

Synthesis of guanidine-functionalized and nickel-functionalized magnetic biochar nanoparticles (MBC-Guanidine-Ni) was done through a multi-step protocol, including pyrolysis, precipitation of Fe 3 O 4 , silane grafting, guanidine modification and coordination of nickel to magnetic biochar nanoparticles using olive kernel waste. The catalyst that was obtained had a nickel content of 4.14[Formula: see text]wt.% (EDX) and saturation magnetization of 42.01[Formula: see text]emu/g, making it possible to separate the catalyst within less than 20[Formula: see text]s. Successful functionalization, high dispersion of nickel species and good thermal stability up to 300 ∘ C were determined by structural characterization (XRD, FT-IR, TEM, BET, XPS and TGA). A 3 model coupling (benzaldehyde, morpholine, phenylacetylene) reaction optimization studies indicated that in solvent-free conditions at 90 ∘ C with 15[Formula: see text]mg catalyst, propargylamines were produced in a yield of up to 98% within 30–55[Formula: see text]min. The catalyst was reused seven times, successively, with insignificant loss of activity (98–94%). Hot filtration and ICP-OES analysis showed very low nickel leaching (