Activations silver® oxide

Various problems related to the construction and performances of these batteries, such as changes in materials of membranes and additives both to the electrode materials and to the electrolyte, were studied in recent years. Some instability of the silver electrode during such storage period and the ways of avoiding these difficulties were studied and discussed [347]. Reserve activated silver oxide-zinc cells were constructed [348] with synthetic Ag20 and Pb-treated zinc electrodes were produced by a nonelec-trolytic process. The cells were tested before and after thermally accelerated aging. 

The cathode pellet contains Ag20 powder and 1-5% of a conductive carbon powder like graphite, to reduce internal resistance and provide good contact to aU of the active silver oxide particles, mixed with a PTFE binder to maintain the mechanical integrity of the pellet. 

Remotely activated silver oxide-zinc batteries... 

This type of battery can now replace many remotely activated silver oxide-zinc applications, resulting in an equal or smaller size, lightweight battery at lower cost. 

There have been quite a number of measurements of the solubility of amorphous (active) silver oxide however, all of the studies have utilised a temperature in the range of 15-25 °C. The solubility constants that have been reported within this temperature range relate to zero ionic strength and are in relatively reasonable agreement. The relationship of the solubility constant with respect to temperature is illustrated in Figure 12.3. Due to the small range in temperature, only a linear relationship between the solubility constants and the inverse of absolute temperature can be assumed. 

Oxidation States. The common oxidation state of silver is +1, ie,, as found in AgCl, which is used with Mg in sea- or freshwater-activated batteries (qv) AgNO, the initial material for photographic materials, medical compounds, catalysts, etc and silver oxide, Ag20, an electrode in batteries (see Silver compounds). Few compounds are known. The aqua ion [Ag(H2 O), which has one unpaired electron, is obtained... 

Silver [7440-22-4] Ag, as an active material in electrodes was first used by Volta, but the first intensive study using silver as a storage battery electrode was reported in 1889 (5) using silver oxide—iron and silver oxide—copper combinations. Work on silver oxide—cadmium followed. In the 1940s, the use of a semipermeable membrane combined with limited electrolyte was introduced by Andrir in the silver oxide—2inc storage battery. 

A. Silver trifluoroacetate. To a suspension of 187 g. (0.81 mole) of silver oxide (Note 1) in 200 ml. of water is added 177 g. (1.55 moles) of trifluoroacetic acid (Note 2). The resulting solution is filtered, and the filtrate is evaporated to dryness under reduced pressure. The dry silver trifluoroacetate thus obtained is purified by placing it in a Soxhlet thimble and extracting with ether, or by dissolving the salt in 1.2 1. of ether, filtering through a thin layer of activated carbon, and evaporating the filtered ether solution to dryness. The yield of colorless crystalline salt obtained after removal of the ether is 300 g. (88%). 

In acidic electrolytes only lead, because it forms passive layers on the active surfaces, has proven sufficiently chemically stable to produce durable storage batteries. In contrast, in alkaline medium there are several substances basically suitable as electrode materials nickel hydroxide, silver oxide, and manganese dioxide as positive active materials may be combined with zinc, cadmium, iron, or metal hydrides. In each case potassium hydroxide is the electrolyte, at a concentration — depending on battery systems and application — in the range of 1.15 - 1,45 gem"3. Several elec-... 

Zinc-silver oxide batteries as primary cells are known both as button cells, e.g., for hearing aids, watches, or cameras, and for military applications, usually as reserve batteries. Since the latter after activation have only a very short life (a few seconds to some minutes), a separation by cellulo-sic paper is generally sufficient. 

P.E. Streigle, Activator Investigation For A Silver Oxide—Zinc Battery (U) , Catalyst Research Corp, Md, Rept No 2, AADLPA Contract No DA-28-017-AMC-3433(A) (1967)... 

Alkyl halides can be hydrolyzed to alcohols. Hydroxide ion is usually required, except that especially active substrates such as allylic or benzylic types can be hydrolyzed by water. Ordinary halides can also be hydrolyzed by water, if the solvent is HMPA or A-methyl-2-pyrrolidinone." In contrast to most nucleophilic substitutions at saturated carbons, this reaction can be performed on tertiary substrates without significant interference from elimination side reactions. Tertiary alkyl a-halocarbonyl compounds can be converted to the corresponding alcohol with silver oxide in aqueous acetonitrile." The reaction is not frequently used for synthetic purposes, because alkyl halides are usually obtained from alcohols. 

In the same way, the stability of nitromethane,nitroethane and 1-nitropropane are very much weakened by the presence of metal oxides. A study that was carried out on twenty four oxides showed that the most active are cobalt, nickel, copper and silver oxides and especially dichromium and diferric trioxides, which cause nitroethane to detonate at 245°C. 

Interaction of chlorine with methane is explosive at ambient temperature over yellow mercury oxide [1], and mixtures containing above 20 vol% of chlorine are explosive [2], Mixtures of acetylene and chlorine may explode on initiation by sunlight, other UV source, or high temperatures, sometimes very violently [3], Mixtures with ethylene explode on initiation by sunlight, etc., or over mercury, mercury oxide or silver oxide at ambient temperature, or over lead oxide at 100°C [1,4], Interaction with ethane over activated carbon at 350°C has caused explosions, but added carbon dioxide reduces the risk [5], Accidental introduction of gasoline into a cylinder of liquid chlorine caused a slow exothermic reaction which accelerated to detonation. This effect was verified [6], Injection of liquid chlorine into a naphtha-sodium hydroxide mixture (to generate hypochlorite in situ) caused a violent explosion. Several other incidents involving violent reactions of saturated hydrocarbons with chlorine were noted [7],... 

If the activation energies for the epoxidation and combustion reactions on silver oxide equal E, then the rate coefficients k in equations (14) can be expressed as... 

The silver catalyst was prepared by reducing silver oxide. The silver oxide used was prepared by adding a solution of potasium hydroxide to an aqueous solution of silver nitrate. A small amount of 0.3% K SO solution was added to the silver oxide powder as a promoter and, after mixing, was dried at 105°C for 24hr in a dark room. This was coated on a-A O of 20-42 mesh in the presence of a small amount of ethanol until the sample reached a size of 12-14 mesh. After the ethanol in the silver oxide powder had been completely vaporized in air at room temperature, the sample was reduced in a reactor with a flow of for 12 hr at 50°C and successively for 12 hr at 100°C. The composition of the catalyst so prepared was 206.0 g-Ag, 1.132 g-K S0 / 5 3.5 g-A O. The BET surface area was 0.3 m / g-A.g. HThe constant activity of this catalyst was obtained by flowing the mixture of 5% C H, 20% 0 and 75% He at 91°C for 48 hr. 1... 

Hibernia A process for making formaldehyde by the partial oxidation of methane by ozonized oxygen. The catalyst is barium peroxide activated with silver oxide. Developed in Germany during World War II but not commercialized. 

Acetimidate formation with A-methylacetamide and acylated glycosyl halides according to Sinay et al (212,213), using three equivalents of silver oxide as an activator, leads neither to particularly stable nor to reactive donors. Any other developments along these lines have already been summarized in previous reviews (1,3). The same is mainly true for anomeric... 

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