Ruthenium IV oxide

Miscellaneous. Ruthenium dioxide-based thick-film resistors have been used as secondary thermometers below I K (92). Ruthenium dioxide-coated anodes ate the most widely used anode for chlorine production (93). Ruthenium(IV) oxide and other compounds ate used in the electronics industry as resistor material in apphcations where thick-film technology is used to print electrical circuits (94) (see Electronic materials). Ruthenium electroplate has similar properties to those of rhodium, but is much less expensive. Electrolytes used for mthenium electroplating (95) include [Ru2Clg(OH2)2N] Na2[Ru(N02)4(N0)0H] [13859-66-0] and (NH 2P uds(NO)] [13820-58-1], Several photocatalytic cycles that generate... 

Ruthenium (IV) oxide [12036-10-1] M 133.1, d 6.97. Freed from nitrates by boiling in distilled water and filtering. A more complete purification is based on fusion in a KOH-KNO3 mix to form the soluble ruthenate and perruthenate salts. The melt is dissolved in water, and filtered, then acetone is added to reduce the ruthenates to the insoluble hydrate oxide which, after making a slurry with paper pulp, is filtered and ignited in air to form the anhydrous oxide [Campbell, Ortner and Anderson Anal Chem 33 58 1961]. 

Effect of Catalyst Composition. Where acetic is the typical acid substrate, effective ruthenium catalyst precursors include ruthenium(IV) oxide, hydrate, ruthenium(III) acetyl-acetonate, triruthenium dodecacarbonyl, as well as ruthenium hydrocarbonyls, in combination with iodide-containing promoters like HI and alkyl iodides. Highest yields of these higher MW acids are achieved with the Ru02-Mel combination,... 

Figure 1 illustrates the first order dependence upon initial ruthenium oxide concentrations for [MeI]/[Ru] ratios in the range >10. This first order dependence is observed only up to a ruthenium(IV) oxide charge of 2 mmole (i.e. [Ru]... 

Deuteration studies with acetic acid-d4 (99.5% atom D) as the carboxylic acid building block, ruthenium(IV) oxide plus methyl iodide-d3 as catalyst couple and 1/1 (C0/H2) syngas, were less definitive (see Table III). Typical samples of propionic and butyric acid products, isolated by distillation in vacuo and glc trapping, and analyzed by NMR, indicated considerable scrambling had occurred within the time frame of the acid homologation reaction. 

Similar acetic acid conversions and higher acid yield distributions using ruthenium(IV) oxide in combination with methyl iodide, ethyl iodide and hydrogen iodide as the added iodide promoter under comparable conditions. This is consistent with these different starting materials ultimately forming the same catalytically active species. 

Syngas Homologation of Acetic Acid. To a N2-flushed liquid mix of acetic acid (50.0 gm) and methyl iodide (5.67 gm, 40 mmole), set in a glass liner is added 0.763 gm of ruthenium(IV) oxide, hydrate (4.0 mmole). The mixture is stirred to partially dissolve the ruthenium and the glass liner plus contents charged to a 450 ml rocking autoclave. The reactor is sealed, flushed... 

A highly selective conversion of 1,6-anhydro-4-0-benzyl-2-deoxy-2-fluoro-/ -D-glucopyranose (12) into the corresponding 3-oxo derivative 13 is carried out by rulhcnium(VIII) oxide generated in situ from ruthenium(IV) oxide and sodium periodate.199... 

Ruthenium(IV) oxide-Sodium periodate, 268 Ruthenium tetroxide, 268 Tetrachlorotris [ bis (1,4-diphenylphos-phine)butane]diruthenium, 288 Tetrakis(trifluoroacetate)ruthenium, 289... 

Ruthenium(III) hydroxide is formed by the action of alkali on a solution of ruthenium(III) chloride. It is easily oxidized by air to the tetravalent state, The dioxide, R11O2, forms when the metal is heated in air. Hydrous ruthenium(IV) oxide can be precipitated by adding alcohol to a less than 3-M NaOH solution of ruthenium(VIII) oxide, followed by boiling. Above 3-complete reduction is not obtained. The hydrous oxide that is soluble in concentrated HQ tends to occlude impurities. 

A procedure using ruthenium(IV) oxide and sodium metaperiodate43 was chosen initially for 44. Protected 4-keto-L-proline derivative 47 was obtained in 76% yield, a reaction that could be satisfactorily repeated on several occasions using the same batch of ruthenium(IV) oxide (Scheme 15). Attempts to repeat the procedure using different batches of ruthe-nium(IV) oxide, however, gave variable results, the exact reasons for this not being clear. 

V- Ruthenium(IV)oxide, acetonitrile, water, carbontetrachloride, sodium periodate... 

Oxidation of allylic alcohols. Ruthenium(IV) oxide, particularly the hydrate, is more efficient than MnO, for oxidation of allylic alcohols to the corresponding aldehydes. Only catalytic amounts are required if the oxidation is conducted under oxygen. An antioxidant is also required to prevent further oxidation. Either system oxidizes primary allylic alcohols in high yield (76-98%) yields arc lower in oxidations of secondary allylic alcohols. 

In view of the purification and waste disposal problems with the chromium oxidations catalytic methods with ruthenium catalysts are more attractive. Ruthenium(Vlll) oxide is a strong oxidant that will also oxidize alkenes, alkynes, sulfides, and in some cases benzyl ethers. The method is compatible with glycosidic linkages, esters and acetals, and is usually carried out in a biphasic solvent system consisting of water and a chlorinated solvent. Acetonitrile or a phase-transfer catalyst has been shown to further promote the oxidation [29,30]. Normally, a periodate or a hypochlorite salt serve as the stoichiometric oxidant generating rutheni-um(VIII) oxide from either ruthenium(IV) oxide or ruthenium(III) chloride [30]. 

Ruthenium(VIII) oxide is generated in situ during the reaction using another oxidizing agent, usually sodium metaperiodate, but sodium hypochlorite has also been used. Ruthenium sources are usually ruthenium(III) chloride or ruthenium(IV) oxide, preferably as hydrates, but w-bis(bipyridyl)dichlororuthenium dihydrate... 

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