Silver oxide reaction

Barteau, M.A. Madix, R. J. The Surface Reactivity of Silver Oxidation Reactions, The Chemical Physics of Solid and Heterogeneous Catalysis, ESPC, vol. 4, 1982, pp. 96-142. 

M. A. Barteau and R. J. Madix, The surface reactivity of silver oxidation reactions, Chem. Phys. Solid Surf. Heretog. Catalysis, Vol. 4 (D. A. King and D. R Woodruff, eds.), Elsevier, Amsterdam, 1982, p. 95. 

Introduce a solution of 15 g. of the diazo ketone in 100 ml. of dioxan dropwise and with stirring into a mixture of 2 g. of silver oxide (1), 3 g. of sodium thiosulphate and 5 g. of anhydrous sodium carbonate in 200 ml. of water at 50-60°. When the addition is complete, continue the stirring for 1 hour and raise the temperature of the mixture gradually to 90-100°. Cool the reaction mixture, dilute with water and acidify with dilute nitric acid. Filter off the a-naphthylacetic acid which separates and recrys-talhse it from water. The yield is 12 g., m.p. 130°. 

The benzyl group has been widely used for the protection of hydroxyl functions in carbohydrate and nucleotide chemistry (C.M. McCloskey, 1957 C.B. Reese, 1965 B.E. Griffin, 1966). A common benzylation procedure involves heating with neat benzyl chloride and strong bases. A milder procedure is the reaction in DMF solution at room temperatiue with the aid of silver oxide (E. Reinefeld, 1971). Benzyl ethers are not affected by hydroxides and are stable towards oxidants (e.g. periodate, lead tetraacetate), LiAIH, amd weak acids. They are, however, readily cleaved in neutral solution at room temperature by palladium-catalyzed bydrogenolysis (S. Tejima, 1963) or by sodium in liquid ammonia or alcohols (E.J. Rcist, 1964). 

Silver Catalyst Process. In early formaldehyde plants methanol was oxidized over a copper catalyst, but this has been almost completely replaced with silver (75). The silver-catalyzed reactions occur at essentially atmospheric pressure and 600 to 650°C (76) and can be represented by two simultaneous reactions ... 

Sahcylaldehyde is readily oxidized, however, to sahcyhc acid by reaction with solutions of potassium permanganate, or aqueous silver oxide suspension. 4-Hydroxybenzaldehyde can be oxidized to 4-hydroxybenzoic acid with aqueous silver nitrate (44). Organic peracids, in basic organic solvents, can also be used for these transformations into benzoic acids (45). Another type of oxidation is the reaction of sahcylaldehyde with alkaline potassium persulfate, which yields 2,5-dihydroxybenzaldehyde (46). 

Alkyl hahdes in the presence of silver oxide react with alkyl malates to yield alkoxy derivatives of succinic acid, eg, 2-ethoxysuccinic acid, H00CCH2CH(0C2H )C00H (12,13). A synthetic approach to produce ethers of malic acid is the reaction of malic esters and sodium alkoxides which affords 2-alkoxysuccinic esters (14). 

Propylene oxide is also produced in Hquid-phase homogeneous oxidation reactions using various molybdenum-containing catalysts (209,210), cuprous oxide (211), rhenium compounds (212), or an organomonovalent gold(I) complex (213). Whereas gas-phase oxidation of propylene on silver catalysts results primarily in propylene oxide, water, and carbon dioxide as products, the Hquid-phase oxidation of propylene results in an array of oxidation products, such as propylene oxide, acrolein, propylene glycol, acetone, acetaldehyde, and others. 

Silver Carbonate. Silver carbonate, Ag2C02, is produced by the addition of an alkaline carbonate solution to a concentrated solution of silver nitrate. The pH and temperature of the reaction must be carefully controlled to prevent the formation of silver oxide. A suspension of Ag2C02 is slightly basic because of the extensive hydrolysis of the ions present. Heating soHd Ag2C02 to 218°C gives Ag20 and CO2. 

Silver(Il) oxide is a strong oxidant. Reactions ia alkaline medium have been studied extensively (19). It decomposes ia aqueous solution unless stabilized with concentrated nitric acid. 

Silver sulfate has been described as a catalyst for the reduction of aromatic hydrocarbons to cyclohexane derivatives (69). It is also a catalyst for oxidation reactions, and as such has long been recommended for the oxidation of organic materials during the deterrnination of the COD of wastewater samples (70,71) (see WASTES, INDUSTRIAL WATER, INDUSTRIAL WATERTTEATI NT). 

Zinc—Silver Oxide Batteries. Miniature 2inc—silver oxide batteries have a 2inc anode, and a cathode containing silver oxide [20667-12-3] Ag20. The cathode reaction... 

The cathode reaction involves reduction of silver oxide to metallic silver [7440-22-4J. The reaction is a two-phase, heterogeneous reaction producing a substantially constant voltage during discharge. Some manganese dioxide may be added to the cathode, as in the case of mercury oxide cells. 

Analogous to the oxidation of hydrazones to azo compounds, A-unsubstituted pyrazolidines are oxidized to A -pyrazolines. For example, the blcyclic pyrazolidine (415) when treated with silver oxide yields the pyrazoline (416) (65JA3023). Pyrazolidine (417) is transformed into the perchlorate of the pyrazolium salt (411) by reaction with mercury(II) acetate in ethanol followed by addition of sodium perchlorate (69JOU1480). 

The decomposition of silver oxide was one of the earhest solid reactions studied. It is smoothly reversible below 200°C (392°F) with equation for partial pressure of oxygen,... 

The silver oxide was prepared by adding, with manual stirring, 66 g. of 98% sodium hydroxide (1.62 moles) in 2 1. of water to a solution of 274 g. (1.62 moles) of silver nitrate in 500 ml. of water. The precipitate was collected by filtration and washed with water until free from alkali. The wet cake can be dried or preferably used moist for reaction with trifluoroacetic acid. 

Fire Hazards - Flash Point Not flammable Flammable Limits in Air (%) Not flammable Fire Extinguishing Agents Not pertinent Fire Extinguishing Agents Not To Be Used Not pertinent Special Hazards of Combustion Products Not pertinent Behavior in Fire Decomposes to silver oxide, silver, and carbon dioxide. The reaction is non violent Ignition Temperature Not pertinent Electrical Hazard Not pertinent Burning Rate Not pertinent. 

EtOH). No methoxyl is present. It forms a series of crystalline double chlorides with cadmium, zinc or copper, does not give the thalleioquin reaction, and solutions of its sulphate are not fluorescent. It is diacidie and forms two series of salts of which the nitrate, B. HNOj, crystallises in minute prisms, m.p. 196°, insoluble in water. Cinchonamine hydrochloride, B. HCl, laminae or B. HCl. HjO, cubical crystals, has been suggested for use in the estimation of nitrates. When warmed with strong nitric acid the alkaloid furnishes dinitrocinchonamine. It gives an amorphous, monoacetyl derivative, and forms a methiodide, m.p. 208 , which with silver oxide yields an amorphous methylcinchonamine. Raymond-Hamet found that cinchonamine ves typical indole colour reactions and is probably an indole alkaloid. This seems to have been... 

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