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    Composites of Palladium-Nickel Alloy Nanoparticles and Graphene Oxide for the Knoevenagel Condensation of Aldehydes with Malononitrile
    (Amer Chemical Soc, 2019) Lolak, Nabih; Kuyuldar, Esra; Burhan, Hakan; Göksu, Haydar; Akocak, Süleyman; Şen, Fatih
    Herein, we have described uniformly dispersed palladium-nickel nanoparticles furnished on graphene oxide (GO-supported PdNi nanoparticles) as a powerful heterogeneous nanocatalyst for the promotion of Knoevenagel reaction between malononitrile and aromatic aldehydes under mild reaction conditions. The successful characterization of PdNi nanoparticles on the GO surface was shown by X-ray diffraction, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy (HR-TEM), and TEM. GO-supported PdNi nanoparticles, which are used as highly efficient, stable, and durable catalysts, were used for the first time for the Knoevenagel condensation reaction. The data obtained here showed that the GO-supported PdNi nanocatalyst had a unique catalytic activity and demonstrated that it could be reused five times without a significant decrease in the catalytic performance. The use of this nanocatalyst results in a very short reaction time under mild reaction conditions, high recyclability, excellent catalytic activity, and a straightforward work-up procedure for Knoevenagel condensation of malononitrile and aromatic aldehydes.
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    A Novel Hydrogenation of Nitroarene Compounds with Multi Wall Carbon Nanotube Supported Palladium/Copper Nanoparticles (PdCu@MWCNT NPs) in Aqueous Medium
    (Nature Publishing Group, 2020) Goksu, Haydar; Zengin, Nursefa; Burhan, Hakan; Cellat, Kemal; Sen, Fatih
    A novel nanocatalyst, multi-wall carbon nanotube supported palladium/copper (PdCu@MWCNT) nanoparticles, was synthesized for the reduction of nitroarene compounds. Characterization of the nanocatalyst was achieved by XRD, XPS, TEM, and Raman spectroscopy analysis. In this study, the hydrogenation of nitroarenes to primary amine compounds was achieved in aqueous medium at room temperature. The aniline derivatives were synthesized with high yields at mild conditions via novel PdCu@MWCNT nanocatalyst. The conversion of nitroarenes to amine derivatives was accomplished at 99% efficiency. In addition to its high activity, the PdCu@MWCNT catalyst was determined to be stable and reusable after the 3rd consecutive use for the reaction and provided 99% conversion of various compounds in the reduction reaction.
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    Oxidation of Benzyl Alcohol Compounds in the Presence of Carbon Hybrid Supported Platinum Nanoparticles (Pt@CHs) in Oxygen Atmosphere
    (Nature Research, 2020) Göksu, Haydar; Burhan, Hakan; Mustafov, Sibel Demiroğlu; Şen, Fatih
    A novel catalyst which carbon hybrid supported platinum nanoparticles were synthesized by our group for the oxidation of benzyl alcohol derivatives. In this study, this catalyst was utilized for the oxidation of benzyl alcohol derivatives to benzaldehyde compounds in aqueous toluene at 80 °C. The benzaldehyde derivatives were synthesized in high yields and mild conditions in the presence of the catalyst by the developed method. Additionally, the prepared nanoparticles have been characterized by Transmission Electron Microscopy (TEM), the high-resolution electron micrograph (HR-TEM), X-ray Photoelectron Spectroscopy (XPS), and X-ray Diffraction (XRD). The mean particle size of the nanoparticles determined by the XRD technique was found to be 2.83 nm in parallel with TEM analysis. TEM analysis also indicated that the Pt nanoparticles were evenly dispersed on the support material. Finally, the Pt@CHs catalyst was shown also stable and reusable for the oxidation reaction, providing ?95% conversion after its 3rd consecutive use in the oxidation reaction of various compounds. © 2020, The Author(s).
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    Synthesis of benzylidenemalononitrile by Knoevenagel condensation through monodisperse carbon nanotube-based NiCu nanohybrids
    (Nature Publishing Group, 2020) Zengin, Nursefa; Burhan, Hakan; Savk, Aysun; Goksu, Haydar; Sen, Fatih
    Monodisperse nickel/copper nanohybrids (NiCu@MWCNT) based on multi-walled carbon nanotubes (MWCNT) were prepared for the Knoevenagel condensation of aryl and aliphatic aldehydes. The synthesis of these nanohybrids was carried out by the ultrasonic hydroxide assisted reduction method. NiCu@MWCNT nanohybrids were characterized by analytical techniques such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM), and Raman spectroscopy. According to characterization results, NiCu@MWCNT showed that these nanohybrids form highly uniform, crystalline, monodisperse, colloidally stable NiCu@MWCNT nanohybrids were successfully synthesized. Thereafter, a model reaction was carried out to obtain benzylidenemalononitrile derivatives using NiCu@MWCNT as a catalyst, and showed high catalytic performance under mild conditions over 10-180 min.