Transition metal ions supported on hydrogels as hydrogenation catalysts
TL;DR: In this article, the synthesis of new hydrogel polymers based on 2-hydroxyethyl methacrylate and other functional monomers is described, which are useful for anchoring palladium and rhodium species.
About: This article is published in Journal of Molecular Catalysis.The article was published on 1990-06-01. It has received 12 citations till now. The article focuses on the topics: Catalyst support & Catalysis.
Citations
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TL;DR: In this paper, the synthesis and use of nitrogen-containing copolymers for anchoring Ru(II) and Rh(I) species is described, and the supported species are effective as catalysts for the decomposition of H 2 O 2 in aqueous medium at neutral pH.
Abstract: The synthesis and use of nitrogen-containing copolymers for anchoring Ru(II) and Rh(I) species is described. The supported species are effective as catalysts for the decomposition of H 2 O 2 in aqueous medium at neutral pH. The polymers as well as the supported catalysts have been characterised by physical and chemical methods. The effects of [H 2 O 2 ], catalyst loading and pH of the medium on the rate of decomposition have been studied. Suitable mechanisms have been proposed to account for the kinetics. Recycling efficiencies of the catalysts are found to be good.
16 citations
15 citations
TL;DR: In this paper, a comparison of chiral rhodium(I) complex catalysts of the type [Rh(L)PP*]A (L = cyclic diolefin; PP* = chiral bis(phosphane) and A = anion like BF) regarding their hydrogenating activity against prochiral substrates was made.
Abstract: Kinetic Investigations of the Hydrogenation of Ligands in Catalyst Precursors for Asymmetric Reduction of Prochiral Olefines1
The comparison of chiral rhodium(I) complex catalysts of the type [Rh(L)PP*]A (L = cyclic diolefin; PP* = chiral bis(phosphane) and A = anion like BF) regarding their hydrogenating activity against prochiral substrates is hampered by the induction period in the hydrogen consumption which can be attributed to the formation of the catalytically active species from the diolefin precatalyst. The competing hydrogenation of diolefin [e.g. cis,cis-cycloocta-1,5-diene (COD), norborna-2,5-diene (NBD)] and prochiral substrate may cause a maximum of the hydrogenation rate, which is characteristic for different catalyst/substrate/solvent systems. Michaelis-Menten rate constants for the hydrogenation of COD and NBD were determined for different chiral catalysts by stoichiometric and catalytic hydrogenations. The rate constants differ for one selected diolefin up to a factor of 40. The hydrogenation of NBD is generally 5–8 times faster than the COD hydrogenation. In the special case of precatalysts based on he-xopyranoside bis(phosphinites) the rate constants for the NBD hydrogenation in comparison with those for COD are higher up to a factor of 48. In some cases the hydrogenation of the mono-ene is faster than that of the diolefin (e.g. COD, NBD). The high hydrogenation rate reported in the literature for some precatalysts in the asymmetric hydrogenation of prochiral olefins is caused in part by the relatively fast diolefin hydrogenation which facilitates the complete formation of the catalyst. The influence of substrate, solvent, and some experimental conditions on the induction period will be discussed.
14 citations
01 Jan 1994
TL;DR: The subject of supported metal complexes as catalysts was reviewed by Hartley in a book published in 1985 [1] and hydrogenation was extensively treated by Yermakov and Arzamaskova as mentioned in this paper.
Abstract: The subject of supported metal complexes as catalysts was reviewed by Hartley in a book published in 1985 [1], and hydrogenation was extensively treated. Supported metal complexes as hydrogenation catalysts were also reviewed by Yermakov and Arzamaskova in 1986 [2], and enantioselective versions of the reaction by Hetflejs in the same year [3]. Therefore account will focus on work published since 1984.
12 citations
TL;DR: In this paper, a polymer-supported palladium-imidazole catalyst was used to catalyze the hydrogenation of various olefins under mild conditions, and the rate of hydrogenation was studied.
9 citations
References
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TL;DR: The rate of oxidation is not significantly affected by the activity of the reaction medium down to a pH of 2.0, but falls markedly as pH is reduced further, and the mechanism of oxidation of thiosulphate has been suggested based on product distribution and kinetics.
24 citations
TL;DR: In this article, a polymer-supported Pd(II) species has been prepared by means of an oxidative addition reaction between Pd (PPh 3 ) 4 and chloromethylated crosslinked polystyrene.
23 citations
TL;DR: In this article, a new type of catalyst has been prepared consisting of small particles of transition type metals uniformly dispersed in a swollen, nonporous, polymer gel and the activity and selectivity of such catalysts have been investigated in several hydrogenation reactions.
22 citations
TL;DR: In this article, the authors showed that quaternisation increases catalytic activity of the poly(4-vinylpyridine) complex for the oxidation of S2O2−3 by O2 compared with PVP----Cu(II) without quaternization.
20 citations
TL;DR: In this article, a study of the catalytic activity of copper(II) complexes of 2,2′-bipyridine and several other similar chelating ligands having pyridine nuclei was conducted.
16 citations