- Efficient magnetically separable heterogeneous platinum catalyst bearing imidazolyl schiff base ligands for hydrosilylation
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Reported herein is a magnetically separable heterogeneous nano catalyst Fe3O4@SiO2-biIMI- PtCl2, which is prepared by firstly applying a SiO2 coating onto readily synthesized magnetite nanoparticles via the hydrolysis condensation of tetraethyl orthosilicate (TEOS) under basic conditions, then modifying it using aminopropyl triethoxysilane and bis(imidazole) aldehyde, and finally incorporating a PtCl2 complex via coordination chemistry. The chemical structure and morphology of the nanocatalyst as well as the valence state and content of platinum within this catalyst were carefully characterized. This catalyst can mediate the hydrosilylation between 1-octene and hydrosilane, with the conversion of 1-octene reaching up to 99%, and it shows good regioselectivity as only β-adducts are identified. In addition, this catalyst can be reused for at least 5 cycles. The hydrosilylation reaction between different olefins and hydrosilanes can also be efficiently mediated by Fe3O4@SiO2-biIMI-PtCl2.
- Huo, Yingpeng,Hu, Jiwen,Tu, Yuanyuan,Huang, Zhenzhu,Lin, Shudong,Luo, Xiaojiong,Feng, Chao
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- Platinum-Pyridine Schiff base complexes immobilized onto silica gel as efficient and low cost catalyst for hydrosilylation
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A heterogeneous platinum catalyst with tridentate pyridine Schiff base ligands supported on silica gel is reported. The catalyst was fully characterized via FTIR, solid-state 13C NMR spectroscopy, X-ray photoelectron spectroscopy (XPS), N2 adsorption/desorption analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The catalyst showed potential application in mediating hydrosilylation reactions between olefins and hydrosilanes, and it can be reused for at least five cycles.
- Huo, Yingpeng,Hu, Jiwen,Liu, Feng,Wu, Jiapei,Zhang, Yikun,Zhang, Yalan,Wang, Qianyi
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p. 812 - 818
(2021/07/25)
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- Waste-free and efficient hydrosilylation of olefins
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High purity silicone precursors can now be synthesized by hydrosilylation of solvent-free olefins catalyzed by a highly stable and active glass hybrid catalyst consisting of mesoporous organosilica microspheres doped with Pt nanoparticles. These findings open the door to the sustainable manufacture of silicone and a way to further reduce the amount of platinum in silicones, which are ubiquitous advanced polymers with multiple uses and applications.
- Pandarus, Valerica,Ciriminna, Rosaria,Gingras, Geneviève,Béland, Fran?ois,Kaliaguine, Serge,Pagliaro, Mario
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p. 129 - 140
(2019/01/11)
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- Platinum(II) complexes bearing bulky Schiff base ligands anchored onto mesoporous SBA-15 supports as efficient catalysts for hydrosilylation
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Reported herein is an easy-to-prepare novel heterogeneous catalyst of platinum complexes bearing binary ligands of bidentate naphthalenolimine and cyclo-1,5-octadiene that are anchored onto mesoporous silica SBA-15. The presence of the binary ligands not only stabilized the platinum, but also enabled the platinum atoms to form nanoclusters with diameters of ca 1?nm, and led to high platinum loading (8.69?wt%). Moreover, the platinum catalyst exhibited high catalytic activity towards hydrosilylation of terminal alkenes and styrene with silanes under mild and solvent-free conditions, with excellent regioselectivity.
- Huo, Yingpeng,Hu, Jiwen,Lin, Shudong,Ju, Xingming,Wei, Yanlong,Huang, Zhenzhu,Hu, Yangfei,Tu, Yuanyuan
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- Nano-dispersed platinum(0) in organically modified silicate matrices as sustainable catalysts for a regioselective hydrosilylation of alkenes and alkynes
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Nano-dispersed platinum(0) particles stabilized in a range of organically modified silicate (ORMOSIL) matrices are investigated as sustainable catalysts for the hydrosilylation of alkenes and alkynes. In this study, five different siloxane matrices including triethoxysilane (HTEOS), methyltriethoxysilane (MTES), ethyltriethoxysilane (ETES), triethoxyvinylsilane (TEVS) and propyltriethoxysilane (PTES) are investigated, and the distribution of the metal particles in these materials analyzed by transition electron microscopy (TEM). The particles appeared to be generally of a small size, with a diameter of ca. 2-5 nm in each of these catalysts, however the distribution is not equally uniform from one matrix to the other. HTEOS, MTES and ETES that respectively carry a hydrogen, a methyl and an ethyl group on the triethoxysilane moiety, displayed a more uniform distribution, while particles appeared to be more scattered in the remaining matrices. Catalysts with a uniform particles distribution produced higher and consistent yields, while those with poor particles distribution produced lower and almost random yields, suggesting that the uniformity in particle distribution, and by extension the nature of the siloxane matrix, are important for the catalytic properties of these materials. The scope of the reaction was broadened to a range of olefins, with a goal of investigating the tolerability of the reaction toward a number of reactive functional groups, resulting in the preparation of 28 compounds. This catalytic system also enabled the hydrosilylation of a limited number of alkynes under the optimized reaction conditions.
- Duke, Brett J.,Akeroyd, Evan N.,Bhatt, Shreeja V.,Onyeagusi, Chibueze I.,Bhatt, Shreya V.,Adolph, Brandy R.,Fotie, Jean
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p. 11782 - 11795
(2018/07/25)
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- Hydrosilylation of alkenes catalyzed by rhodium with polyethylene glycol-based ionic liquids as ligands
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A series of polyethylene glycol-functionalized imidazolium ionic liquids has been prepared and characterized. These ionic liquids have been successfully applied in the hydrosilylation of alkenes catalyzed by rhodium complexes. The effects of the length of the polyether chain, the amount of ionic liquid, and the reaction temperature on the catalytic performance of hydrosilylation have been investigated. Furthermore, the catalytic system has been tested for the hydrosilylation of different alkenes with triethoxysilane. The new catalytic system exhibits both excellent catalytic activity and selectivity under low-temperature conditions. The catalyst system could be recycled five times with slightly deactivation.
- Xu, Yisong,Bai, Ying,Peng, Jiajian,Li, Jiayun,Xiao, Wenjun,Lai, Guoqiao
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- Preparation of organically modified silicon dioxides
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Process for the preparation of modified, porous silicon dioxides by the hydrolytic polycondensation of tetraalkoxysilanes or polyalkoxysiloxanes in the heterogenous phase in the presence of an organoalkoxysilane.
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