Peroxydisulfate silver

Aminonocatdicinic acid, 428 2-Aminopyridine, 18 Ammonium peroxydisulfate-Silver... 

ALKOXYCARBONYLATION, QUINONES Ammonium peroxydisulfate-Silver nitrate. 

Alkylation of protonated nitrogen heterocycles (e.g., pyridines, quinolines) can be accomplished by treatment with a carboxylic acid, silver nitrate, sulfuric acid, and ammonium peroxydisulfate. The R group can be primary, secondary, or tertiary. The attacking species is R% formed by " ... 

Oxidation of the complexes [Ag(Py)4][MoF6] and [Ag(Py)2][UF6] in acetonitrile by MoF6 and UF6, respectively, leads to the silver(III) compounds [Ag(Py)4(NCMe)][MoF6]3 and [Ag(Py)2(NC-Me)3][UF6]3, which are strong oxidizing agents.167 Other pyridine silver(III) complexes have been obtained by oxidation of silver nitrate and ammonia with ammonium peroxydisulfate in aqueous... 

Acyl radicals have been obtained from a-keto acids by silver-catalyzed decarboxylation with peroxydisulfate. Decarboxylation takes place easily and can be interpreted according to Scheme 10. 

The usual sources used for the homolytic aromatic arylation have been utilized also in the heterocyclic series. They are essentially azo- and diazocompounds, aroyl peroxides, and sometimes pyrolysis and photolysis of a variety of aryl derivatives. Most of these radical sources have been described in the previous review concerning this subject, and in other reviews concerning the general aspects of homolytic aromatic arylation. A new source of aryl radicals is the silver-catalyzed decarboxylation of carboxylic acids by peroxydisulfate, which allows to work in aqueous solution of protonated heteroaromatic bases, as for the alkyl radicals. 

Silver(I) catalyzed oxidative decarboxylation using peroxydisulfate is well studied . Decarboxylated carbon radicals can form a C—C bond with 1,4-benzoquinone or 1,4-naphthoquinone (equation 17) . In the case of 1,4-benzoquinone and phenylacetic acid the yield is 87%, whereas in the case of 2-methyl-l,4-naphthoquinone and cyclopropanecar-boxylic acid the yield is as low as 37%. 

The first Ag(II) compound to be isolated in the solid state was tetra-kis(pyridine)silver(2 +) peroxydisulfate.13,14 Its stability can be attributed to its insolubility, the coordination of the Ag(II) ion, and the presence of an anion with an element in a high oxidation state. It can be prepared conveniently, rapidly, and in high yield by reaction of a solution containing silver nitrate and pyridine with a solution of potassium peroxydisulfate. The corresponding, but less stable, nitrate can be prepared by the electrolytic oxidation of silver nitrate in concentrated aqueous pyridine.15... 

Twenty grams (0.074 mol) of potassium peroxydisulfate is dissolved in 1800 mL of ice-cold water contained in a 3-L beaker. Eight milliliters of pyridine (0.1 mol) is added to a solution of 2.00 g (0.0118 mol) of silver nitrate in 40 mL of water, and the resulting solution is slowly added with stirring to the potassium peroxydisulfate solution. 

Anal. A freshly dried sample of product is added to water, aqueous ammonia is added, and the suspension is boiled for 15 min to destroy the complex and to reduce the Ag(II) to Ag(I) and the peroxydisulfate to sulfate. The resulting solution is acidified with dilute hydrochloric acid, and the silver is determined as silver chloride. Peroxydisulfate is determined by precipitation of the sulfate in the filtrate with barium chloride. Calcd. for Ag(C5H5N)4S208 Ag, 17.50 S2Oi-, 31.17. Found Ag, 17.90 S20 ", 31.32. 

Peroxydisulfate oxidations have also been used to prepare a variety of pyridine mono- and di-carboxylic add silver(II) complexes.496 All these compounds were orange-red in colour and sparingly soluble to insoluble in most solvents, including water. 

Mono and bis 2,2 -bipyridyl and 1,10-phenanthroline complexes of silver(II) have been isolated as red-brown crystals by either peroxydisulfate, anodic or ozone oxidation techniques.497,519 No tris-chelated species have been substantiated,497 although it is worth noting that a 2,2, 2"-terpyridyl bis complex has been isolated and claimed to be a six-coordinate... 

The first preparation of a silver(III) biguanide was as a result of attempts to prepare a silver(II) derivative of ethylenebis(biguanide) (91). 566 Oxidation of a silver(I) salt by sodium peroxydisulfate in the presence of the ligand, however, gave the red silver(III) derivative instead. 

Water Silver nitrate Barium chloride Peroxydisulfates, S2082- On boiling, decomposes into the sulfate, free sulfuric acid, and oxygen Black precipitate of silver peroxide On boiling or standing for some time, forms precipitate of barium sulfate... 

Results with Silver Composition in Water with 10 ppm K2S2Os. For Salmonella, for the lower initial bacteria level (104), the following log reductions were recorded 0.26 at 0 minutes, 0.28 at 20 minutes, 0.35 at 60 minutes, and 0.58 at 240 minutes. For the higher initial bacteria level (106), the following log reductions were recorded 0.03 at 0 minutes, 0.16 at 20 minutes, 0.21 at 60 minutes and 0.36 at 240 minutes. The results indicate that the 10 ppm silver with 10 ppm potassium peroxydisulfate (K2S2Os) embodiment of this invention provides an effective bactericidal effect for Salmonella on beef steak. 

Silver (II) oxide has been made by the hydrolytic action of boiling water on a substance of the approximate formula Ag708N03, a material which is obtained by the electrolytic oxidation of silver(I) nitrate solutions.1-4 A more rapid and convenient process for the preparation of this oxide involves the oxidation of silver (I) nitrate by means of potassium peroxydisulfate in an alkaline medium.5,6... 

Seventy-two grams of sodium hydroxide (1.8 mols) in pellet form is added portionwise, with constant stirring, to 1 1. of water, which is maintained at approximately 85°. Seventy-five grams of potassium peroxydisulfate (0.28 mol) in the form of an aqueous slurry is added to the hot alkaline solution this is followed by the addition of 51 g. of silver(I) nitrate (0.30 mol) dissolved in a minimum amount of water. The temperature of the resulting mixture is raised to 90°, and stirring is continued for approximately 15 minutes. 

Minisci s group developed homolytic substitution reactions of electron-poor arenes or hetarenes providing alkylarenes and -hetarenes extensively (see also Part 2, Sect. 2.5). The state of the art was reviewed thoroughly, so that the methodology is illustrated only by selected examples [435, 436, 437]. A protocol using silver nitrate as the catalyst and sodium peroxydisulfate as the stoichiometric oxidant proved to be very useful for the catalytic oxidative generation of radicals [438]. 

Alkyl radicals for such reactions are available from many sources such as acyl peroxides and alkyl hydroperoxides, particularly by the oxidative decarboxylation of carboxylic acids using peroxydisulfate catalyzed by silver. Pyridine and various substituted pyridines have been alkylated at the 2-position in high yields by these methods. Quinoline similarly reacts at the 2-position, isoquinoline at the 1-position, and acridine at the 9-position. Pyrazine and quinoxaline also give high yields of 2-substituted alkyl derivatives <1974AHC(16)123>. 

Toluene has been oxidized by the silver ion catalysed reaction with peroxy-disulfate. The reaction produces a mixture of bibenzyl, benzaldehyde and benzoic acids.299 Russian workers have described the conversion of 4-methoxy-toluene to the benzaldehyde by oxidation with peroxydisulfate in the presence of silver or copper ions and oxalic acid.300 The presence of copper salts in iron or copper catalysed peroxydisulfate oxidation is believed to suppress side-reactions.301 Phillips have patented a palladium(II)/tin(IV)/persulfate system for the oxidation of toluene derivatives.302 The reactions are carried out in carboxylic acid solvents (Figure 3.78). 

In 1970, Anderson and Kochi (99) reported a silver-mediated oxidative decarboxylation reaction with peroxydisulfate as the oxidant. Kinetic studies showed that the reaction is first order in both silver and peroxydisulfate and zero order in carboxylic acid. Silver(II) species and alkyl radicals are considered intermediates. 

A mixed-valence silver(I)-silver(III) cryptate complex has been synthesized by condensation of tris(3-aminopropyl)amme and terephthaldehyde in the presence of AgNOs. Other pyridine silver(III) complexes have been obtained by oxidation of silver nitrate and ammonia with ammonimn peroxydisulfate in aqueous ammonia solution. An air-stable diamagnetic silver(III) complex of a N-confused tetraphenylporphyrin, 5,10,15,20-tetraphenyl-2-aza-21-carboporphyrin argentate(III), has been described. ... 

The nucleophilic radicals formed by the silver-catalyzed, oxidative decarboxylation of carboxylic acids by peroxydisulfate ions attack protonated imidazoles mainly at the 2-... 

Quinazoline is quantitatively converted into 2- ert-butylquinazolin-4(3//)-one by treating it in aqueous solution with an excess of pivalic acid and ammonium peroxydisulfate at pH 0-1 in the presence of a catalytic amount of silver nitrate. At pH 5 where the concentration of a covalent hydrate is too small to influence the course of the reaction, it is converted into a mixture of 2-rcrr-butylquinazoline, 4-rc-Tr-butylquinazoline, and 2,4-di-to7-butylquinazoline in a ratio of 4 3 2. ° ... 

Homogeneous oxidants Peroxydisulfate ion, S20g (often called persulfate), is a strong oxidant in acid solution in the presence of silver ion as catalyst. The reaction... 

Solid oxidants Sodium bismuthate is such a strong oxidant that it wiU oxidize Mn(II) to permanganate at room temperature. Ce(III) is oxidized quantitatively to Ce(rV) in sulfuric acid solution, and the excess bismuthate removed by filtration. Silver-catalyzed peroxydisulfate oxidation has largely supplanted the bismuthate method, thus avoiding the inconvenient filtration stq> required with solid oxidants. 

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