14799-93-0Relevant articles and documents
High surface area polystyrene resin-supported Pt catalysts in room temperature solventless octene hydrosilylation using methyldichlorosilane
Drake, Robert,Sherrington, David C.,Thomson, Steven J.
, p. 1523 - 1534 (2002)
Eight macroporous styrene-divinylbenzene-vinylbenzyl chloride resins have been synthesised by suspension polymerisation. The first four employed toluene as the porogen and the second four n-butyl acetate, at a level of 1:1 v/v relative to the comonomers. In all cases a high level of divinylbenzene leads to resins with high surface area, ～ 500 m2 g-1, as determined from a BET treatment of N2 sorption data. The functional group content of each group of four resins was varied from 5-25%. All resins were aminated to generate benzyltrimethylethylenediamine ligands on the polymer matrix, and then each was loaded with Pt(II) using KPtCl4. The analytical data confirmed the formation of ligand PtCl2 molecular complexes. Each of the resin immobilised Pt complexes has been assessed for catalytic activity in the room temperature, solventless, hydrosilylation of oct-1-ene using methyldichlorosilane, and a comparison made with soluble Speier's catalyst under identical conditions. Though less active than the soluble catalyst the activity of all the polymer catalysts is good, and of practical value, the activity being higher than we have previously reported in the case of supports with lower surface area. Furthermore while Speier's catalyst induces significant levels of oct-1-ene isomerisation, isomerisation in the case of the polymer catalysts is much lower, and indeed can be all but eliminated by appropriate washing. Extensive catalyst leaching and recycling studies have been carried out, with the best catalysts showing retention of useful activity after 10 cycles. Careful control experiments have provided strong circumstantial evidence that the isomerisation that does arise with the polymer catalysts can be attributed to a component of leached soluble Pt species. Overall the most active and stable polymer catalyst has the highest surface area (～550 m2 g-1) of those studied, along with the lowest ligand and Pt contents (each ～0.25 mmol g-1). The surface area dependence confirms our earlier view that maximum accessibility to potential metal complex catalytic sites is vital in these systems, and the metal complex loading dependence suggests that generating discrete isolated ligand PtCl2 species provides optimal use of the loaded Pt.
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Nesmeyanov et al.
, (1958)
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Discovering Partially Charged Single-Atom Pt for Enhanced Anti-Markovnikov Alkene Hydrosilylation
Chen, Yuanjun,Ji, Shufang,Sun, Wenming,Chen, Wenxing,Dong, Juncai,Wen, Junfeng,Zhang, Jian,Li, Zhi,Zheng, Lirong,Chen, Chen,Peng, Qing,Wang, Dingsheng,Li, Yadong
, p. 7407 - 7410 (2018)
The hydrosilylation reaction is one of the largest-scale application of homogeneous catalysis and is widely used to enable the commercial manufacture of silicon products. However, considerable issues including disposable platinum consumption, undesired side reactions and unacceptable catalyst residues still remain. Here, we synthesize a heterogeneous partially charged single-atom platinum supported on anatase TiO2 (Pt1δ+/TiO2) catalyst via an electrostatic-induction ion exchange and two-dimensional confinement strategy, which can catalyze hydrosilylation reaction with almost complete conversion and produce exclusive adduct. Density functional theory calculations reveal that unexpected property of Pt1δ+/TiO2 originates from atomic dispersion of active species and unique partially positive charge Ptδ+ electronic structure that conventional nanocatalysts do not possess. The fabrication of single-atom Pt1δ+/TiO2 catalyst accomplishes a reasonable use of Pt through recycling and maximum atom-utilized efficiency, indicating the potential to achieve a green hydrosilylation industry.
Preparation of polycarboxylic acid-functionalized silica supported Pt catalysts and their applications in alkene hydrosilylation
Shao, Dongyun,Li, Youxin
, p. 20379 - 20393 (2018/06/11)
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.
Effect of catalysts on the reaction of allyl esters with hydrosilanes
Belyakova,Pomerantseva,Efimova,Chernyshev,Storozhenko
experimental part, p. 728 - 733 (2011/01/05)
The reaction of hydrosilylation of allyl esters XOCH 2CH=CH 2 (X = MeCO, CF 3CO, C 3F 7CO) and PhOCH 2CH=CH 2 with hydrosilanes HSiY 3 (Y = Cl, OEt) in the presence of the Speier catalyst, the Speier catalyst with additives, and of various nickel complexes was studied. The catalytic hydrosilylation reaction in the presence of the Speier catalyst is accompanied by the reduction. Additives to the Speier catalyst (vinyltriethoxysilane and some ethers) allow to suppress considerably the reduction reaction. In the presence of the studied nickel complexes mainly reduction and isomerization reactions occurred. The best nickel catalysts of hydrosilylation were the mixtures of NiCl 2 or Ni(acac) 2 with phosphine oxides. In contrast to allyl esters, the hydrosilylation of simple olefins proceeds easier, the content of the product of hydrosilylation in the reaction mixture reaches 94.3%. Pleiades Publishing, Ltd., 2010.
