Catalytic carbon dioxide transformation catalysed ruthenium in ionic liquids (original) (raw)
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Catalysis Letters, 2000
The H 2 reduction of RuO 2 hydrate ''dissolved'' in 1-n-butyl-3-methylimidazolium ionic liquids with different counterions, hexafluorophosphate ðBMI Á PF 6 Þ, tetrafluoroborate ðBMI Á BF 4 Þ and trifluoromethane sulfonate ðBMI Á SO 3 CF 3 Þ, is a simple and reproducible method for the preparation of ruthenium nanoparticles of 2.0-2.5 nm diameter size and with a narrow size distribution. The Ru nanoparticles were characterized by TEM and XRD. The isolated Ru nanoparticles are reoxidized in air, whereas they are less prone to oxidation when imbibed in the ionic liquids. These nanoparticles are active catalysts for the solventless or liquid-liquid biphasic hydrogenation of olefins under mild reaction conditions (4 atm, 75 C). The catalytic system composed of nanoparticles dispersed in BMI Á PF 6 ionic liquid is very stable and can be reused several times without any significant loss in the catalytic activity. Total turnover numbers greater than 110 000 (based on total Ru) or 320 000 (corrected for exposed Ru atoms) were attained within 80 h for the hydrogenation of 1-hexene.
Journal of the Brazilian Chemical Society, 2004
A reação de NaBH 4 com RuCl 3 dissolvido no líquido iônico 1-n-butil-3-metilimidazólio hexafluorfosfato (BMI.PF 6 ) é um método simples e reprodutível para a síntese de nanopartículas de RuO 2 estáveis com distribuição estreita e diâmetro da partícula entre 2-3 nm. As nanopartículas de RuO 2 foram caracterizadas por XRD, XPS, EDS e TEM. Estas nanopartículas mostraram alta atividade catalítica tanto na catálise heterogênea quanto na hidrogenação bifásica líquido-líquido de olefinas e arenos sob condições moderadas de reação. Experimentos de envenenamento com Hg(0) e CS 2 , e análises de XRD e TEM de partículas isoladas após a catálise indicaram a formação de nanopartículas de Ru(0). As nanopartículas podem ser reutilizadas em condições de catálise heterogênea até 10 vezes na hidrogenação de 1-hexeno rendendo um número total de ciclos catalíticos de 175.000 para átomos de Ru expostos.
Catalysts, 2017
Development of sustainable energy technologies and reduction of carbon dioxide in the atmosphere are the two effective strategies in dealing with current environmental issues. Herein we report a Dual Function Material (DFM) consisting of supported sodium carbonate in intimate contact with dispersed Ru as a promising catalytic solution for combining both approaches. The Ru-Na 2 CO 3 DFM deposited on Al 2 O 3 captures CO 2 from a flue gas and catalytically converts it to synthetic natural gas (i.e., methane) using H 2 generated from renewable sources. The Ru in the DFM, in combination with H 2 , catalytically hydrogenates both adsorbed CO 2 and the bulk Na 2 CO 3 , forming methane. The depleted sites adsorb CO 2 through a carbonate reformation process and in addition adsorb CO 2 on its surface. This material functions well in O 2 -and H 2 O-containing flue gas where the favorable Ru redox property allows RuO x , formed during flue gas exposure, to be reduced during the hydrogenation cycle. As a combined CO 2 capture and utilization scheme, this technology overcomes many of the limitations of the conventional liquid amine-based CO 2 sorbent technology.
Catalytic carbon dioxide methanation by alumina-supported mono- and polynuclear ruthenium carbonyls
Inorganic Chemistry, 1986
The catalytic activity and selectivity toward methanation of carbon dioxide using several alumina-supported ruthenium-clusterderived catalysts have been studied over the temperature range 180-250 "C. The ruthenium clusters used in these investigations include Ru3(CO) 12r KHRu3(CO), I , [PPN] [HC02Ru3(CO)lo], H4Ru4(CO) 12, KH3Ru4(CO) 12, [PPN] [H3Ru4(CO) 12], and Ru6-C(CO),, (PPN = bis(triphenylphosphine)nitrogen(l+)). Comparative studies were made with the mononuclear complexes RuC13 and Ru(CO)~. The latter species provides a low-valent, organometallic, mononuclear ruthenium source. Catalysts were supported by impregnation over alumina (partially dehydroxylated at 150 OC in vacuo) and activated in hydrogen at 200 "C. Catalyst characterization included diffuse-reflectance infrared spectroscopy, surface area determination, oxygen chemisorption, and electron microscopy. In general, the cluster-derived catalysts were more active than the analogously prepared catalyst obtained from RuC13; e.g., at 180 "C the catalyst derived from RU~C(CO)~, was 22 times more active than that derived from RuC13. The activity of catalysts derived from supported neutral species was observed to increase as the number of ruthenium atoms present in the precursor complex increased; Le., Ru(CO)~ C R U~(C O)~~ < H4R~4(C0)12 < R U~C (C O)~~. Catalysts derived from supported anionic ruthenium cluster derivatives were less active than their neutral counterparts, displaying a great deal of sensitivity to the nature of the accompanying cation. The diffuse-reflectance FTIR spectra of all the supported, activated catalysts originating from low-valent ruthenium derivatives exhibited the same band pattern in the v(C0) region, whereas the RuC13-derived catalyst displayed a quite different v(C0) infrared spectrum upon addition of carbon monoxide.
Organic Letters, 2020
We report the ruthenium-catalyzed cyclization of 1,6-diynes with two molecules of carbon monoxide and water to give a variety of catechols. This reaction likely proceeds through the intermediacy of the water−gas shift reaction to generate an yne− diol-type intermediate followed by a [4 + 2] cycloaddition with 1,6diynes. The reaction requires no external reductants or hydride sources and provides a novel and valuable method for the synthesis of a variety of catechols.
Nanoscale Ru(0) Particles: Arene Hydrogenation Catalysts in Imidazolium Ionic Liquids
Inorganic Chemistry, 2008
The reduction of [Ru(COD)(2-methylallyl) 2 ] (COD) 1,5-cyclooctadiene) dispersed in various room-temperature ionic liquids (ILs), namely, 1-n-butyl-3-methylimidazolium (BMI) and 1-n-decyl-3-methylimidazolium (DMI), associated with the N-bis(trifluoromethanesulfonyl)imidates (NTf 2) and the corresponding tetrafluoroborates (BF 4) with hydrogen gas (4 bar) at 50°C leads to well-dispersed immobilized nanoparticles. Transmission electron microscopy (TEM) analysis of the particles dispersed in the ionic liquid shows the presence of [Ru(0)] n nanoparticles (Ru-NPs) of 2.1-3.5 nm in diameter. Nanoparticles with a smaller mean diameter were obtained in the ILs containing the less coordinating anion (NTf 2) than that in the tetrafluoroborate analogues. The ruthenium nanoparticles in ionic liquids were used for liquid-liquid biphasic hydrogenation of arenes under mild reaction conditions (50-90°C and 4 bar). The apparent activation energy of E A) 42.0 kJ mol-1 was estimated for the hydrogenation of toluene in the biphasic liquid-liquid system with Ru-NPs/BMI • NTf 2. TEM analysis of the ionic liquid material after the hydrogenation reactions shows no significant agglomeration of the [Ru(0)] n nanoparticles. The catalyst ionic liquid phase can be reused several times without a significant loss in catalytic activity.