Ceric perchlorate

Ceric perchlorate oxidises Cl to i Clj according to the rate expression ... 

Oxidation of ketones by ceric perchlorate is catalysed by iridium(III) chloride, particularly in acidic media.320... 

A number of diatomic and polyatomic inorganic radicals have been produced in photochemical systems. Some of these radicals are listed in Table 2. Recently Martin and Swift (189) observed, during the photolysis of ceric perchlorate acid glass, ESR spectra similar to those of methyl radicals and intuitively assigned them to H O radicals. Given that these spectra have been correctly analyzed, it is difficult to understand how their ESR parameters could relate to the 6 radical H O. Confirmation of the assignment must await further detailed study. 17... 

Cerium(IV) is a powerful oxidant having numerous analytical and preparative applications. The kinetics of oxidation of a variety of substrates have been reported. Interpretation of studies of the kinetics of ceric oxidations is complicated by uncertainty regarding Ce(IV) speciation in aqueous solutions. In perchloric acid, Ce(IV) is at its most powerful, characterized by E° = 1.70 V (in 1 M acid, Morss 1985). As this potential is above the oxidation potential of water, its existence in aqueous solutions represents a metastable condition. The speciation of Ce(IV) in perchloric acid is dominated by hydrolytic species, even in moderately strong acid. The various ceric species in HCIO include Ce (aquo ion), CelOH) ", Ce(OH), various Ce(IV)-0-Ce(IV) dimers, and an apparent hydrolytic polymer. The latter two polynuclear species are not observed in ceric perchlorate solutions carefully prepared by electrolysis, leading one to suspect that they are one and the same thing, and perhaps are formed irreversibly in aqueous solutions. 

Aqueous ceric solutions are widely used as oxidants in quantitative analysis they can be prepared by the oxidation of Ce ( cerous ) solutions with strong oxidizing agents such as peroxodisulfate, S20g ", or bismuthate, BiOg". Complexation and hydrolysis combine to render (Ce" +/Ce +) markedly dependent on anion and acid concentration. In relatively strong perchloric acid the aquo ion is present but in other acids coordination of the anion is likely. Also, if the pH is increased, hydrolysis to... 

Hi) The value of Fj is greater with permanganate than with ceric systems. With the latter, the value of Fj is lower for perchloric acid than for sulphuric acid media. 

Sterically hindered, mesityl-substituted, stable enols 72 have been examined with regard to one-electron oxidation. Using two equivalents of a one-electron oxidant such as triarylaminium salts, iron(III)phenanthroline, thianthrenium perchlorate or ceric ammonium nitrate in acetonitrile-benzofurans 73 are obtained in good yields within a few seconds [111]. 

V(phen)32+ has been used as a redox indicator in the titration of FeCl3 by Cr11 and E0 for Ru(bipy)32+ is very high (1.33 V at pH = 0) and the colour change (colourless to yellow) is well marked in the titration of oxalate in 2 M perchloric acid with ceric nitrate. 

Two oxidants essentially dominate these oxidations lead tetraacetate in organic solvents and periodic acid in aqueous media. On occasion, other oxidation reagents cause the cleavage of vicinal diols ceric ammonium nitrate [424], sodium bismuthate [482, 483], chromium trioxide [482, 555], potassium dichromate with perchloric acid [949], manganese dioxide [817], and trivalent [779, 789] or pentavalent [798] iodine compounds. 

The ceric ammonium nitrate solution is standardized against reference sodium oxalate, available from the National Bureau of Standards, in the following manner Transfer a weighed portion of 0.25-0.30 g of the sodium oxalate to a 250-ml beaker, add 100 ml dilute perchloric acid solution, stirring the mixture until the salt is completely dissolved. The solution is cooled to room temperature, 2 drops of the or/Ao-phenanthroline-ferrous ammonium sulfate indicator is added, and the solution is titrated with the ceric ammonium nitrate solution until its color changes from faint red to faint blue. 

The volume of standard ceric ammonium nitrate solution equivalent to 1 ml of ferrous ammonium sulfate solution is determined as follows. A measured portion (approximately 40 ml) of the standard ceric ammonium nitrate is placed in a 250-ml beaker and diluted to 100 ml with the dilute perchloric acid solution. Two drops of the or/ho-phenantlrroline-ferrous ammonium sulfate indicator is added, and the solution is titrated with the ferrous ammonium sulfate solution until a color change from light blue to red is produced. The volume of standard ceric ammonium nitrate solution equivalent to 1 ml of ferrous ammonium sulfate solution is calculated by dividing the volume of the former solution, which was taken for test, by the volume of the latter solution used for titration. 

To eliminate the problem caused by oxidation of the phlegmatizing agents, it is common practice to distill hydrazoic acid from the azide solution or slurry using perchloric acid. The hydrazoic acid (boiling point 35.7°C)is distilled into a known volume of standard ceric ammonium nitrate. The excess ceric ammonium nitrate is titrated with either standard ferrous ammonium sulfate or sodium... 

Distillation ofhydrazoic acid from strong acid solutions is the most common method of separation [12, 17], For small quantities of azide ion in relatively large volumes of solvent, evaporation in alkaline media or carrier precipitation is necessary for the preliminary concentration of azide ions prior to distillation. The distillations are usually made from perchloric acid solutions. A 50-ml round-bottom flask, with a side-arm attached (so that a stream of inert gas passes through the solution) and an air condenser is preferable for distilling hydrazoic acid. The addition of a diluent carrier gas provides added safety. Absorbing solutions for the hydrazoic acid include known, excess quantities of ceric ion. standard base, or a known quantity of ferric perchlorate for colorimetric determination of small quantities of azide ion. The distillation separation is complex and lengthy, but the method is reliable and has universal applicability. 

Ceric ammonium nitrate (CAN), fl, 120-121, before references]. In an acid medium (acetic, formic, perchloric, nitric acid), the reagent oxidizes a single aromatic methyl group in high yield to an aldehyde group but oxidizes a second methyl group only under much more drastic conditions.3... 

Following development of the exposed features, etching of the resist patterns on the mask for many years was done with wet etchants based on a mixture of ceric ammonium nitrate [Ce(NFl4)2(N03)6] and nitric acid, perchloric acid, or... 

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