Osmic acid oxidant

Method A Standardisation with arsenic (III) oxide. Discussion. The most trustworthy method for standardising cerium(IV) sulphate solutions is with pure arsenic(III) oxide. The reaction between cerium(IV) sulphate solution and arsenic(III) oxide is very slow at the ambient temperature it is necessary to add a trace of osmium tetroxide as catalyst. The arsenic(III) oxide is dissolved in sodium hydroxide solution, the solution acidified with dilute sulphuric acid, and after adding 2 drops of an osmic acid solution prepared by dissolving 0.1 g osmium tetroxide in 40mL of 0.05M sulphuric acid, and the indicator (1-2 drops ferroin or 0.5 mL /V-phenylanthranilic acid), it is titrated with the cerium(IV) sulphate solution to the first sharp colour change orange-red to very pale blue or yellowish-green to purple respectively. 

Oxidation of Divinylglycol with Silver Chlorate and Osmic Acid... Ill... 

An amount of 16 g. of the glycol (m. p. 18°) dissolved in 250 ml. of water was oxidized with 18 g. of silver chlorate and 0.3 g. of osmic acid. The reaction mixture yielded 3 g. of allitol and no D,L-mannitol. We may therefore assign the meso configuration to the divinylglycol melting at 18°, since on hydroxylation it yielded allitol, but not D,L-mannitol. 

Oxidation of Divinylglycol with Silver Chlorate and Osmic Acid. In a typical experiment 100 g. of divinylglycol, 118 g. of silver chlorate and 1 g. of osmic acid were dissolved in 6 liters of water. The reaction mixture was kept at room temperature for several days. It was apparently essential that the reaction be carried out rather slowly. 

Oxidation of l,2,5,6-tetraacetoxyhexene-3 led to the formation of dulcitol tetraacetate. In a typical experiment 22 g. of the tetraacetate was oxidized with 4.4 g. of silver chlorate and 0.1 g. of osmic acid and yielded a sirujj which did not crystallize. The sirup was acetylated again and yielded the corresponding hexitol hexaacetate. The crystals which deposited first were collected and recrystallized from methanol, in which they are difficultly soluble in the cold. The product melted at 166-166.5° and analyzed correctly for a hexitol hexaacetate. Now there was found in the collections of the Ecole Normale Sup rieure an old bottle containing dulcitol hexaacetate, m. p. 167-168°. A mixture of the new and the old hexaacetates was found to melt at 166.5-167.5° the identity of the two compounds was thus beyond doubt. 

Osmic Acid Anhydride Osmium Oxide Osmium Tetraoxide Osmium Tetroxide OU1 Dry Agent ... 

Flowever, some associated materials might be perceived as toxic. For example, complexes of osmium find frequent use as electron mediators, because of their rich chemistry, stability, and redox activity. Osmium metal and most compounds are considered nontoxic, but the neat tetroxide of osmium is a strong oxidizer and is considered highly toxic in the U.S. and very toxic by the European Union. On the other hand, the aqueous solution, osmic acid, has been injected at 1% concentration in several European clinical trials, starting in the 1970s, for treatment of arthritis and hemophilia. - No toxic effects were observed. Thus, osmium toxicity might be a question not of in vivo chemistry, but of manufacture, where a concentrated form of the oxide might need to be handled. ... 

Osmic acid, osmic acid anhydride, perosmic oxide. 

The aldehydes 346 and 347 were prepared from the methoxyl derivatives by osmic acid sodium chlorate oxidation and deketalization followed by base-catalyzed condensation in an overall yield of 50%. Acetalization of 346 with /i-toluenesulfonic acid and ethylene glycol in refluxing benzene afforded the acetal 348. The latter has an active site at C-6 suitable for the introduction of oxygen substituents at this position. 

Osmium tetroxide (0s04, sometimes called osmic acid) reacts with alkenes in a concerted step to form a cyclic osmate ester. Oxidizing agents such as hydrogen peroxide (H202) or tertiary amine oxides (R3N+—O-) are used to hydrolyze the osmate ester and reoxidize osmium to osmium tetroxide. The regenerated osmium tetroxide catalyst continues to hydroxylate more molecules of the alkene. 

Osmium Tetroxide, 0s04, frequently but incorrectly known as osmic acid, is the highest oxide of osmium known, and is formed in a variety of ways. Finely divided metallic osmium slowly oxidises in air to the tetroxide, and more rapidly on heating in air or, better, in oxygen.1 At high temperatures the compact metal yields vapours of the volatile tetroxide, and this affords a useful means of quantitatively separating osmium from its iridium alloy (p. S38). 

Osmium tetraoxide (osmic acid) Pentachlorophenol Perchloric acid Phosphorus pentasulfide Phosphorus pentoxide Phosphorus, red Phosphorus, yellow or white Picric acid, trinitrophenol Potassium cyanide Potassium perchlorate Potassium sulfide Potassium, metal Pyridine flammable Selenium Silver oxide Silver cyanide Sodium metal lump Sodium arsenate Sodium arsenite Sodium azide... 

SYNS OSMIC ACID OSMIUM(VIII) OXIDE RCRA WASTE NUMBER P087... 

Transition metal catalysts not only increase the reaction rate but may also affect the outcome of the oxidation, especially the stereochemistry of the products. Whereas hydrogen peroxide alone in acetonitrile oxidizes alkenes to epoxides [729], osmic acid catalyzes syn hydroxylation [736], and tungstic acid catalyzes anti hydroxylation [737]. The most frequently used catalysts are titanium trichloride [732], vanadium pentoxide [733,134], sodium vanadate [735], selenium dioxide [725], chromium trioxide [134], ammonium molybdate [736], tungsten trioxide [737], tungstic acid [737],... 

The starting methoxytetralone (209) was converted by the Stork pyrrolidine-enamine procedure to the alkyltetralone (210). On further alkylation with benzyl chloromethyl ether and sodium hydride in benzene, the latter yielded compound 211, which was oxidized with osmic acid and sodium chlorate in tetrahydrofuran (THF) to give two diastereoisomeric diols (212). The aldehyde 213 was obtained in quantitative yield from compound 212 by treatment with excess metaperiodate in aqueous THF. 

Treatment of (31) with crotyl chloride-potassium carbonate in DMF afforded (33), which was converted into (34) by heating in a sealed tube. Methylation of the phenol (34) with methyl iodide-potassium carbonate gave (35). Osmic acid-sodium periodate oxidation produced the keto-aldehyde (36). Acetalization by standard methods gave the diacetal (37). Reduction of (37) with lithium in liquid ammonia and subsequent toluene-p-sulphonic acid work-up afforded (38) in a yield of 50 %. A vinylogous aldol condensation was effected with methan-olic potassium hydroxide. The resulting mixture was oxidized with chromium... 

SYNONYMS osmic acid, osmium (VIII) oxide, perosmic acid anhydride, perosmic ox-... 

I Synonyms/Trade Names Osmic acid anhydride. Osmium oxide ... 

Synonyms Osmic acid Osmium (VIII) oxide Perosmic acid anhydride Perosmic oxide... 

Osmic acid, perosmic oxide, osmium(IV) oxide)... 

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