Characterization of a Polymer-Bound Palladium Acetate Catalyst and Studies on the Selective Hydrogenation of Dienes and Alkynes
01 Aug 1993-Journal of Macromolecular Science, Part A (Taylor & Francis Group)-Vol. 30, Iss: 8, pp 557-569
TL;DR: In this article, a copolymer support containing pyridyl and carboxyl groups was used to anchor the palladium(II) acetate to the Copolymer Support for the hydrogenation of olefins.
Abstract: Palladium(II) acetate has been anchored onto a copolymer support containing pyridyl and carboxyl groups. XPS studies showed the Pd 3d binding energies for the recovered catalyst to be less by 1 eV after being used in hydrogenation studies. However, x-ray studies and a chemical test based on KCN treatment failed to reveal any palladium oxide or palladium metal formation in the recovered catalyst. It is presumed that an acetate ligand is lost during hydrogenation, which could be the reason for the lowering of the palladium 3d binding energies in the recovered catalyst. Results of investigations of the hydrogenation of olefins and selectivity of the catalyst toward the hydrogenation of dienes and alkynes are presented. The loss of palladium due to leaching under the reaction conditions employed was found to be very low (<1%/cycle).
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TL;DR: A review of the metal complex forming coordination polymers can be found in this paper, where a polymer-metal complex is composed of synthetic polymer and metal ions bound to the polymer ligand by a coordinate bond.
193 citations
TL;DR: It is shown that boiling of the obtained spheres in 28 wt % HNO3 did not affect the shape and bulk structure of the spheres, but led to creation of a considerable amount of surface oxygen-containing functional groups and increase of the content of sp(2) hybridized carbon on the surface.
Abstract: Amorphous, low-porosity carbon spheres on the order of a few micrometers in size were prepared by carbonization of squalane (C30H62) in supercritical CO2 at 823 K. The spheres were characterized and used as catalysts’ supports for Pd. Near-edge X-ray absorption fine structure studies of the spheres revealed sp2 and sp3 hybridized carbon. To activate carbons for interaction with a metal precursor, often oxidative treatment of a support is needed. We showed that boiling of the obtained spheres in 28 wt % HNO3 did not affect the shape and bulk structure of the spheres, but led to creation of a considerable amount of surface oxygen-containing functional groups and increase of the content of sp2 hybridized carbon on the surface. This carbon was seen by scanning transmission electron microscopy in the form of waving graphene flakes. The H/C atomic ratio in the spheres was relatively high (0.4) and did not change with the HNO3 treatment. Palladium was deposited by impregnation with Pd acetate followed by reducti...
38 citations
TL;DR: In this paper, the first thermo-responsive ruthenium catalysts based on poly(propylene imine) dendrimers cross-linked with the poly(ethylene glycol) diglycidyl ether have been prepared for the first time.
Abstract: In this work thermo-responsive ruthenium catalysts, based on the poly(propylene imine) dendrimers cross-linked with the poly(ethylene glycol) diglycidyl ether, have been prepared for the first time. The materials obtained were characterized by X-ray photoelectron spectroscopy and transmission electron microscopy, and tested in the phenol and benzene hydrogenation. Conditions for the metal impregnation into the polymeric matrix were demonstrated to have a great influence both on physical chemical properties of the synthesized catalysts (metal loading, mean particles size, surface structure etc.), and, as a consequence, on their hydrogenation activity and thermo-responsive properties.
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TL;DR: In this paper, the formation of Pd complexes in phosphinated polystyrene resins has been studied, and it is shown that, depending on polymer properties such as the BET surface area and phosphine content, varying amounts of the complex Cl2Pd(pyridine)(PPS)1 are formed in the resin, together with the complex C 2 Pd(P ǫ )2.
20 citations
TL;DR: In this article, the catalysts were found to be active towards the hydrogenation of olefins under ambient conditions (room temperature and 1 atmosphere total pressure) with one catalyst (Cat-I) being active towards hydrogenation.
Abstract: bis-Benzonitriledichloropalladium(II) [(PhCN)2PdCl2] has been supported on two copolymers containing carboxyl and pyridyl groups and has been employed as a catalyst for the hydrogenation of olefins under mild conditions. The coordination environment and the nature of the metal species on the polymer have been studied by IR, ESCA, X-ray and a chemical test based on KCN treatment.
Based on experimental evidence it is proposed that the polymer-palladium complexes initially contain palladium atoms with chlorine atom bridges which are cleaved in the activation. The catalysts were found to be active towards the hydrogenation of olefins under ambient conditions (room temperature and 1 atmosphere total pressure). The kinetic and mechanistic aspects of the hydrogenation of styrene and acrylonitrile and recycling capacity data using one catalyst (Cat-I) are reported.
18 citations
TL;DR: In this paper, the chelating ligand 2,2′-dipyridylmethane can be anchored to styrene-divinylbenzene polymers by reaction of the anion of 2, 2′-methanol with chloromethylated or chloroacetylated resins under mild conditions.
17 citations