- Preparation of polycarboxylic acid-functionalized silica supported Pt catalysts and their applications in alkene hydrosilylation
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A series of novel immobilized platinum catalysts was prepared by loading Pt onto silica particles modified with polycarboxylic acid groups such as diethylenetriaminepentaacetic acid (DTPA), nitrolotriacetic acid (NTA) and succinic acid (SA). The three modified heterogeneous Pt catalysts were characterized using infrared spectroscopy (IR), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDS) and atomic absorption spectroscopy (AAS). The residual H2PtCl6 solutions were characterized using ultraviolet spectroscopy (UV). The polycarboxylic acid-functionalized silica supported Pt catalysts were used to catalyze alkene hydrosilylation and 1-hexene was chosen as a model alkene. The data indicated that the catalytic performance was strongly dependent on the properties of the polycarboxylic acid group bonded to the silica particles. Among them, DTPA-functionalized silica supported Pt (SiO2-DTPA-Pt) showed the best catalytic activity and reusability. Furthermore, some hydrosilylation reactions between other linear alkenes (1-heptene, 1-octene, 1-decene, 1-do-decene, 1-tetra-decene, 1-hexa-decene, 1-octa-decene, styrene or cis-hex-2-ene), or ring type alkenes (norbornene) with methyldichlorosilane could be catalyzed in the presence of these three Pt catalysts. Their high activities were more than 90%, and their selectivities were more than 99%, which were apparently better than homogeneous Pt catalysts. In addition, reactions with cyclohexene were also successfully catalyzed by the Pt catalysts. These results indicate that the polycarboxylic acid-functionalized silica gel supported Pt catalysts have potential value in industrial hydrosilylation reactions.
- Shao, Dongyun,Li, Youxin
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p. 20379 - 20393
(2018/06/11)
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- Fixed-Bed Hydrosilylation Catalyst Complexes and Related Methods
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The invention includes a fixed-bed catalyst complex that includes (i) a metal carbene catalyst, wherein the metal is platinum, and (ii) a catalyst support that includes one or more of silica, alumina and/or glass. The invention provides a fixed-bed catalyst complex that includes a catalyst complex including a carbene chosen from those represented by at least one of Formulae (I), (II), (III), and (IV): Where the vales of X and R1 to R7 are specifically defined. The complex also includes a catalyst support that comprises silica, related reaction products, and related reaction systems.
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Page/Page column 4
(2010/12/29)
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- Sc(OTf)3-mediated silylation of hydroxy functional groups on a solid surface: A catalytic grafting method operating at room temperature
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(Chemical Equation Presented) Surface paradise: Facile catalytic post-grafting of the surface of glass or indium tin oxide (ITO, see picture) with a variety of functional groups has been achieved. Methallylsilanes serve as the grafting reagent and the surfaces show remarkable chemical stability.
- Yeon, Ye-Rim,Park, Young Jun,Lee, Ji-Sung,Park, Jung-Woo,Kang, Sin-Gun,Jun, Chul-Ho
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p. 109 - 112
(2008/09/19)
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- Macrocyclic polyether compounds
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Macrocyclic polyether "crown" compounds of the formula EQU1 WHEREIN T is a C2 -C3 alkylene, A is EQU2 R being H or C1 -C18 alkyl, R2 and R3 being independently C1 -C18 alkyl, C2 -C4 alkenyl, or C6 -C14 aryl; Q and Z are independently 1,2-arylene (or saturated derivatives thereof) or substituted 1,2-arylene (or saturated derivatives thereof); a is 0, 1, 2, or 3; b is an integer from 3 to 20; y is 1 or zero; x1, x2, x3, and x4 are integers independently selected to give a 15-60 atom ring. Such crown compounds are generally useful in the formation of complexes with ionic metal compounds, thus making it possible to use certain chemical reagents in media wherein they are normally insoluble.
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