1. Gold nanoparticles supported on functionalized silica as catalysts for alkyne hydroamination: A chemico-physical insight
- Author
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Ilaria Ragazzini, Chiara Parise, Barbara Ballarin, Paolo Dambruoso, Daniele Nanni, Elisa Boanini, Davide Barreca, Maria Cristina Cassani, Parise C., Ballarin B., Barreca D., Cassani M.C., Dambruoso P., Nanni D., Ragazzini I., and Boanini E.
- Subjects
Gold nanoparticle ,Materials science ,General Physics and Astronomy ,02 engineering and technology ,010402 general chemistry ,Heterogeneous catalysis ,01 natural sciences ,Hydroamination ,Catalysis ,Heterogeneous catalysi ,chemistry.chemical_compound ,Gold nanoparticles ,Surfaces and Interfaces ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,0104 chemical sciences ,Surfaces, Coatings and Films ,Silanol ,Solid state NMR spectroscopy ,Phenylacetylene ,chemistry ,Chemical engineering ,Colloidal gold ,Propynylcarbamate-functionalized silica ,Surface modification ,0210 nano-technology ,Selectivity - Abstract
Highly stable gold nanoparticles anchored on propynylcarbamate-functionalized silica (Au/SiO2@Yne) have been efficiently utilized for the heterogeneous hydroamination of phenylacetylene with aniline under different reaction conditions. In order to ascertain the eventual influence of surface silanol groups on the system activity and selectivity tailored modifications of Au/SiO2@Yne catalysts were pursued according to two different strategies, involving respectively functionalization with trimethylethoxysilane (Au/SiO2@Yne-TMS) or post-treatment with triethylamine (Au/SiO2@Yne-NEt3). The prepared materials were analysed by several complementary techniques such as Solid State NMR (SS NMR), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD). A comparison of the resulting catalytic activities with that of the pristine Au/SiO2@Yne revealed a significant improvement for Au/SiO2@Yne-NEt3 in terms of both conversion and selectivity. Recycling and stability studies showed a catalytic activity decrease after the first run, due to the formation of polyphenylacetylene (PPhA) oligomers shielding the active sites. PPhA removal by sonication in acetone fully restored the catalytic activity and empowered the system with a good operational stability, a very crucial issue in view of eventual practical applications.
- Published
- 2019