Ceric nitrate

Synonyms ammonium ceric nitrate ammonium hexanitratocerate (IV)... 

Ceric ammonium nitrate is prepared by electrolytic oxidation of cerous nitrate in nitric acid to ceric nitrate, followed by the addition of ammonium nitrate solution. It is separated from the solution by crystaUization. It may be prepared alternatively by dissolving cerium(II) oxide, Ce0 H20 in concentrated nitric acid followed by treatment with ammonium nitrate. 

The oxalates obtained above, alternatively, are digested with sodium hydroxide converting the rare earth metals to hydroxides. Cerium forms a tetravalent hydroxide, Ce(OH)4, which is insoluble in dilute nitric acid. When dilute nitric acid is added to this rare earth hydroxide mixture, cerium(lV) hydroxide forms an insoluble basic nitrate, which is filtered out from the solution. Cerium also may be removed by several other procedures. One such method involves calcining rare earth hydroxides at 500°C in air. Cerium converts to tetravalent oxide, Ce02, while other lanthanides are oxidized to triva-lent oxides. The oxides are dissolved in moderately concentrated nitric acid. Ceric nitrate so formed and any remaining thorium nitrate present is now removed from the nitrate solution hy contact with tributyl pbospbate in a countercurrent. 

Wine, P. H R. L. Mauldin, III, and R. P. Thorn, Kinetics and Spectroscopy of the NO, Radical in Aqueous Ceric Nitrate-Nitric Acid Solutions, /. Phys. Chem., 92, 1156—1162 (f988). 

On the other hand, chemicals might be chosen as agents for generation of active centers in the polymeric backbone and grafting of monomer in the vapor phase. Ammonium persulfate and styrene (189), acrylic acid (190), butyl acrylate (191), potassium persulfate and n-butyl maleate or 2-ethyl hexyl acrylate (55,134) and ammonium ceric nitrate and methacrylic add (192) are examples of this method. Benzoyl peroxide deposited on polycaprolactam fibers initiates the grafting of styrene in vapor phase (193). 

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. 

The polymerization of acrylamide initiated by ceric nitrate-3-chloro-l-propanol redox systems. J. Polymer Sci. 38, 393 (1959). 

In general, the acetylenic triple bond is highly reactive toward hydrogenation, hydroboration, and hydration in the presence of acid catalyst. Protection of a triple bond in disubstituted acetylenic compounds is possible by complex formation with octacarbonyl dicobalt [Co2(CO)g Eq. (64) 163]. The cobalt complex that forms at ordinary temperatures is stable to reduction reactions (diborane, diimides, Grignards) and to high-temperature catalytic reactions with carbon dioxide. Regeneration of the triple bond is accomplished with ferric nitrate [164], ammonium ceric nitrate [165] or trimethylamine oxide [166]. 

As the leachant circulates and approaches reflux temperature, an electrical potential is applied across the electrodes in the oxidizer tank that converts the cerous nitrate into a mixture of cerous and ceric nitrates. Since the latter species are either neutral or anions in solution, it is not necessary to separate the electrodes with a diaphragm in the electrolytic oxidation tank. However, the cathode is partly shielded with a cylindrical finger that surrounds it and air-sparged to remove nitrous acid which does reduce the ceric species. 

Incinerator ashes are decontaminated simply by loading them into a separate, stirred electrolytic oxidizer tank. The cathode in this tank is partly shielded from the anode and air-sparged to remove nitrous acid. After several hours of leaching at reflux, the excess ceric nitrates may be reduced with oxalic acid, the... 

Compounds with Ceric Nitrate Alcohol Reagent. 

Ceric nitrate, Ce(N03) 4, is not known as a simple salt, but double nitrates of the type Ce(N03)4 2 M N03 are formed with the alkali metals and ammonium. In aqueous solutions these salts are readily hydrolyzed, but they are the most stable ceric salts. The ammonium ceric nitrate is important in the purification of cerium. A series of double nitrates, M (N03)2 Ce(N03)4 8 H2O, is also formed, but they are less stable than the alkali double salts. When ceric hydroxide is evaporated with nitric acid, crystals of the basic salt 2 Ce0H(N03)2 9 H2O are obtained. 

II. Indirect Oxidations and the Eleetrolytic Preparation of Ceric Nitrate, Eiectrochimica Acta, 33, 509 (1988b). 

In all cases, however, dissolution of irradiated fuel in nitric acid leaves some plutonium associated with undissolved fission products. This plutonium can be leached from the residue with mixed nitric and hydrofluoric acids or with mixed nitric acid and ceric nitrate, Ce(N03)4 [U2]. Residue from irradiated mixed UO2-PUO2 fuel was 99.94 percent dissolved in 4 h by treatment with 4 M HNO3-O.5 M Ce(IV). Ceric nitrate is preferred to HF in the secondary dissolution step because cerium is already present as a fission product, and its addition does not complicate subsequent solvent extraction. Use of Ce(IV) in the primary dissolution step is undesirable because it would convert all plutonium to the less extractive hexavalent state and would volatilize much of the ruthenium as RUO4. 

Chromium is readily etched by aqueous solution of ceric salt, prepared from ceric nitrate, percholoric acid, and water. Chrome masks are now being fabricated with this type of etchant solution. ... 

Oxidation with ceric nitrate has been developed as a new degradative procedure in the study of bisbenzylisoquinoline alkaloids. This reagent splits lau-danosine to veratric aldehyde and the N-methyl-6,7-dimethoxy-3,4-dihy-droisoquinolinium ion, isolated as veratryl alcohol and N-methyl-3,4-dimethoxytetrahydroisoquinoline after reduction. In the same way, tetrandrine, hernandezine, and O-methylmicranthine have been degraded to the bis-tetra-hydroisoquinolines (48 R = H), (48 R = OMe), and (49), the second product in each case being the diphenyl ether (50). ... 

In nitric acid solutions the potential is somewhat lowered ( ° = 1.61 V in 1.0 M HNO3), suggesting a partial complexation of the Ce " " aquo ion by nitrate. The stability and stoichiometry of soluble ceric nitrate complexes is not well established, but certainly must include at least CeNOj and probably Ce(N03)2 or mixed Ce(IV) OH-NO3 species. Since nitrate complexes are intermediate in stability between those of perchlorate (barely perceptible) and sulfate (moderately strong), cerium(IV) speciation in nitric acid probably also includes hydrolytic species. Ceric ammonium nitrate, (NH ljCefNOj), is a preferred ceric reagent, because it appears to minimize irreversible polymerization of Ce(IV). 

Oxidation of (XVIII) with ceric nitrate gives a dimer of cyclobutadiene and other products (Section VI, C). In the presence of acetylenes the bicyclohexadienes (CIII) can be isolated they isomerize to the benzenes (CIV) on heating. 

Ammonium ceric nitrate / , -Ethyleneoxo compds. by cyclobutane ring opening... 

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