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Ruthenium tetroxide catalyst

The sequence has been applied to the synthesis of 1,4-cyclohexanedione from hydroquinone 10), using W-7 Raney nickel as prepared by Billica and Adkins 6), except that the catalyst was stored under water. The use of water as solvent permitted, after hltration of the catalyst, direct oxidation of the reaction mixture with ruthenium trichloride and sodium hypochlorite via ruthenium tetroxide 78). Hydroquinone can be reduced to the diol over /o Rh-on-C at ambient conditions quantitatively (20). [Pg.129]

Almost all the materials which are being considered as components in automobile exhaust catalyst are somewhat toxic (74)- Most of the compounds considered are low vapor pressure solids which can only escape from the exhaust system as very fine airbone dust particles formed by catalyst attrition. A few compounds, such as the highly toxic metal carbonyls and ruthenium tetroxides, are liquid under ambient conditions and have boiling points less than 100 °C. These compounds are not present in... [Pg.81]

The ruthenium tetroxide dioxide catalytic system is effective for the oxidation of alkanols, although it will also react with any alkene groups or amine substituents that are present. The catalyst can be used in aqueous acetonitrile containing tetra-butylammonium hydroxide with platinum electrodes in an undivided cell Primary alcohols are oxidised to the aldehyde and secondary alcohols to the ketone [30]. Anodic oxidation of ruthenium dioxide generates the tetroxide, which is the effective oxidising agent. [Pg.265]

Aliphatic alcohols can be oxidized to ketones, aldehydes, or carboxylic acids using oxoruthenium(IV)complexes as redox catalyst or clectrogenerated ruthenium tetroxide In the latter case, a double mediator system is used in which an electrochemically generated active chlorine species (Cl or CP ) oxidizes RuO to RUO4 (Eq. (29)). [Pg.17]

Reformatsky reaction, 511, 599 Reissert compounds, 150 Resistomycin, 450 Resorcinols, 66, 460-461 Retinal, 120 Retrolactonization, 17 Rhodium(ll) carboxylates, 458-460 Rhodium catalysts, 460 Rhodium(III) chloride, 460-461 Rhodium(III) porphyrins, 461-462 Rifamyem S, 133, 134 Ruthenium(III) chloride, 462 Ruthenium tetroxide, 462-463... [Pg.338]

Deacetylation of 80 in methanolic sodium methoxide and successive O-isopropyli-denation with 2,2-dimethoxypropane gave 2-0-acetyl-3,4-O-isopropylidene-l,6-an-hydro-pseudo-p-DL-galactopyranose (81), after acetylation. Removal of the acetyl group of 81, followed by oxidation with ruthenium tetroxide and sodium metaperiodate afforded the 2-oxo derivative (82). Catalytic hydrogenation of 82 under the presence of platinum catalyst and acetolysis in a mixture of acetic acid, acetic anhydride and sulfuric acid gave pseudo-P-DL-talopyranose pentaacetate (83) [25] (Scheme 17). [Pg.266]

Transition metal oxidants such as permanganate, ruthenium tetroxide and diromium(VI) oxide are convenient and efficient reagents for routine cleavage reactions. The use of phase transfer catalysts (quaternary ammonium and phosphonium ions, primarily) has made it possible to solubilize transition metal oxides such as permanganate and chromatt in nonaqueous solvents, and to therdry increase the scope of these reactions substantially. ... [Pg.542]

Diarylacetylenes are converted in 55-90% yields into a-diketones by refluxing for 2-7 h with thallium trinitrate in glyme solutions containing perchloric acid [413. Other oxidants capable of achieving the same oxidation are ozone [84], selenium dioxide [509], zinc dichromate [660], molybdenum peroxo complex with HMPA [534], potassium permanganate in buffered solutions [848, 856, 864,1117], zinc permanganate [898], osmium tetroxide with potassium chlorate [717], ruthenium tetroxide and sodium hypochlorite or periodate [938], dimethyl sulfoxide and iV-bromosuccin-imide [997], and iodosobenzene in the presence of a ruthenium catalyst [787] (equation 143). [Pg.91]

The unusual oxidant nickel peroxide converts aromatic aldehydes into carboxylic acids at 30-60 °C after 1.5-3 h in 58-100% yields [934. The oxidation of aldehydes to acids by pure ruthenium tetroxide results in very low yields [940. On the contrary, potassium ruthenate, prepared in situ from ruthenium trichloride and potassium persulfate in water and used in catalytic amounts, leads to a 99% yield of m-nitrobenzoic acid at room temperature after 2 h. Another oxidant, iodosobenzene in the presence of tris(triphenylphosphine)ruthenium dichloride, converts benzaldehyde into benzoic acid in 96% yield at room temperature [785]. The same reaction with a 91% yield is accomplished by treatment of benzaldehyde with osmium tetroxide as a catalyst and cumene hydroperoxide as a reoxidant [1163]. [Pg.177]

Ruthenium tetroxide was shown to oxidize PCBs in water [20], Water-soluble ruthenium complexes, such as [Ru(H20)2(DMS0)4]2+, are effective catalysts for the KHSO5 deep oxidation of a number of chloroaliphatics, of a-chlorinated al-kenes, polychlorobenzenes, and polychlorophenols. When the reactions are carried out in water in the presence of surfactant agents, degradation of the substrates is definitely faster. Aromatic substrates are mainly converted into HC1 and C02, polychlorophenols being more sensitive to oxidation than substituted benzenes [21]. Replacement of the DMSO- solvated ruthenium by RuPcS results in a definite improvement of the reaction course with hydrogen peroxide, since dismutation of... [Pg.608]

However, oxidation of the 26-diethylaminoethylthio derivative of pristinamycin IIb (94a), or the corresponding sulfinyl analog (97), using ruthenium tetroxide generated in situ from a catalytic amount of ruthenium dioxide with sodium metaperiodate as the co-oxidant, afforded the desired 26-diethylamino-sulfonyl derivative (98) in good yield. Alternative ruthenium catalysts included ruthenium trichloride or tris(triphenylphosphine)ruthenium(II) chloride. [Pg.244]

Side reactions can be avoided with a selective oxidizing agent such as ruthenium tetroxide (453) which is soluble in many solvents. It can be used in catalytic quantities in combination with another oxidizing agent, eg, peracetic acid (454). Ruthenium dioxide in combination with periodate can be used in water or in organic solvents in the presence of a phase transfer catalyst (424,425). [Pg.8235]


See other pages where Ruthenium tetroxide catalyst is mentioned: [Pg.109]    [Pg.79]    [Pg.80]    [Pg.81]    [Pg.914]    [Pg.698]    [Pg.20]    [Pg.277]    [Pg.1751]    [Pg.38]    [Pg.410]    [Pg.1390]    [Pg.206]    [Pg.681]    [Pg.673]    [Pg.7177]    [Pg.7178]    [Pg.313]    [Pg.364]    [Pg.394]    [Pg.277]    [Pg.723]   
See also in sourсe #XX -- [ Pg.101 ]




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