Copper/silver salts

In similar circumstances, silver salts leave a residue of metallic silver lead and copper salts usually leave a residue of the corresponding oxide calcium and barium salts leave a resirlne of the carbonate or oxide. Identify the metal in all such cases by the usual tests of qualitative inorganic analysis. Metals other than the above are seldom encountered in elementan qualitative analysis. 

Acetylene Bromine, chlorine, brass, copper and copper salts, fluorine, mercury and mercury salts, nitric acid, silver and silver salts, alkali hydrides, potassium metal... 

Ethynyl carbinols rearrange to conjugated unsaturated aldehydes. Copper or silver salts cataly2e isomeri2ation of the acetate to an aHenic acetate, which can be hydroly2ed to an unsaturated aldehyde (204). 

Electrorefining. Electrolytic refining is a purification process in which an impure metal anode is dissolved electrochemicaHy in a solution of a salt of the metal to be refined, and then recovered as a pure cathodic deposit. Electrorefining is a more efficient purification process than other chemical methods because of its selectivity. In particular, for metals such as copper, silver, gold, and lead, which exhibit Htfle irreversibHity, the operating electrode potential is close to the reversible potential, and a sharp separation can be accompHshed, both at the anode where more noble metals do not dissolve and at the cathode where more active metals do not deposit. 

Electrical and Electronic Applications. Silver neodecanoate [62804-19-7] has been used in the preparation of a capacitor-end termination composition (110), lead and stannous neodecanoate have been used in circuit-board fabrication (111), and stannous neodecanoate has been used to form patterned semiconductive tin oxide films (112). The silver salt has also been used in the preparation of ceramic superconductors (113). Neodecanoate salts of barium, copper, yttrium, and europium have been used to prepare superconducting films and patterned thin-fHm superconductors. To prepare these materials, the metal salts are deposited on a substrate, then decomposed by heat to give the thin film (114—116) or by a focused beam (electron, ion, or laser) to give the patterned thin film (117,118). The resulting films exhibit superconductivity above Hquid nitrogen temperatures. 

Permanent coloration can also be achieved by exposing hair to certain metals copper, silver, and especially lead salts. Preparations containing aqueous solutions of lead acetate may include a source of sulfur, usually thiosulfate, which may react with cystine in the hair to produce some cysteine or may react directiy with the metal ion to form dark metallic sulfides. Preparations of this type, which darken hair gradually, are not universally considered safe. 

Pyridazines form complexes with iodine, iodine monochloride, bromine, nickel(II) ethyl xanthate, iron carbonyls, iron carbonyl and triphenylphosphine, boron trihalides, silver salts, mercury(I) salts, iridium and ruthenium salts, chromium carbonyl and transition metals, and pentammine complexes of osmium(II) and osmium(III) (79ACS(A)125). Pyridazine N- oxide and its methyl and phenyl substituted derivatives form copper complexes (78TL1979). 

The pyrolysis of perfluoro carboxylic salts can result both in mono and bimolecular products At 210-220 °C, silver salts give mostly the coupled products, at 160-165 °C in A -methylpyrrolidinone, the corresponding copper salts also give the simple decarboxylated compounds in nearly equal amounts The decomposition of the copper salts m the presence of lodobenzene at 105-125 °C results m a phenyl derivative, in addition to the olefin and coupled product [94] (equations 60-62)... 

Most simple inorganic salt solutions cause virtually no attack on aluminium-base alloys, unless they possess the qualities required for pitting corrosion, which have been considered previously, or hydrolyse in solution to give acid or alkaline reactions, as do, for example, aluminium, ferric and zinc chlorides. With salts of heavy metals —notably copper, silver, and gold —the heavy metal deposits on to the aluminium, where it subsequently causes serious bimetallic corrosion. 

The precipitate is curdy (compare silver chloride) and is readily coagulated by boiling. It is washed with dilute ammonium thiocyanate solution a little sulphurous acid or ammonium hydrogensulphite is added to the wash solution to prevent any oxidation of the copper)I) salt. 

Cyclization of bromostilbenes 6 to dibenz[/ ,/]oxepins 7 can be achieved by irradiation in excellent yield.102 103 Under solvolytic conditions (60% NaOH, EtOH), the yield is greatly reduced. When a silver salt (AgOAc) is used, however, complete conversion to the tricyclic system is accomplished.102 Tribenz[/>,catalyzed cyclization of biphenyl-2-yl 2 -chlorosulfonylphenyl ether in 44% yield.260... 

Potassium peroxodisulphate (K2S2Og) also oxidizes sulphoxides to sulphones in high yield, either by catalysis with silver(I) or copper(II) salts at room temperature85 or in pH 8 buffer at 60-80 °c86-88. The latter conditions have been the subject of a kinetic study, and of the five mechanisms suggested, one has been shown to fit the experimental data best. Thus, the reaction involves the heterolytic cleavage of the peroxodisulphate to sulphur... 

This group showed that isolable silver(I) diaminocarbene complexes can be use in situ instead of free carbenes, to generate the copper carbene complex. The silver salts that precipitates during the formation of the copper complex have not any negative effect on the conversion. This method is advantageous since most of the silver complexes are isolable, air-stable and easily obtained by treatment of the corresponding imidazohnium salt by 0.5 equiv of silver oxide (Scheme 53). The solid structure of 78 was analyzed by X-ray diffraction. 

As no simple copper-perrhenate salts previously existed to serve as a model for structural relationships to [Cu2(pzc)2(H20)2Re04], our attention turned to the syntheses of the isoelectronic silver-perrhenate systems. Shortly after an analysis of the structure above, a synthesis of the new pyrazine-pillared (=pyz) AgRe04(pyz) solid was found [30], and is shown in Fig. 17.3 alongside the re-... 

The barium salt explodes weakly on heating, and the copper salt and silver salt strongly on heating or friction. 

Use of copper and silver salts in ethylenediamine solution provides a method for catalytic H2 reduction of nitroalkanes to oximes (541) ... 

Sulphide-type phosphors are produced from pure zinc or cadmium sulphide (or mixtures thereof) and heating them together at about 1000 °C with small quantities (0.1-0.001 per cent) of copper, silver, gallium, or other salts, which are termed activators. 

Association constants for salts of copper, silver, and thallium appear to reflect solvation in a fairly simple way. For example, of the perchlorate salts, only those of the poorly solvated thallium ion show association. 

Example Polystyrenes ranging from PS 2200 to PS 12500 form [M+metal] ions with Ag" and Cu" ions when silver or copper(I) salts are admixed to the sample preparation, hi case of PS 12500, both metal ions were found to effect cationi-zation equally well, i.e., without causing differences in average molecular weight or ionic abundances (Fig. 10.12). [106]... 

As the result of hydrolysis a complex mixture of all, or nearly all, the previously mentioned units is obtained. These have been isolated by various methods based upon the fractional crystallisation of the compounds themselves, or of their copper, silver and other salts. Only when one or more of the amino acids occurred in somewhat large amounts was their isolation and characterisation effected their amount seldom reached a value higher than 20 per cent, of the total quantity and the remainder was represented by uncrystallisable syrups of unknown nature. A great advance was made when Drechsel discovered that the protein molecule contained diamino acids as well as monoamino acids, and to Kossel and Kutscher we owe our chief knowledge concerning their isolation and estimation. Emil Fischer, in igoi, by his... 

Iron also exhibits single replacement reactions, precipitating less electropositive metals out of their salt solutions. Thus, sohd iron can reduce many metals, such as copper, silver, gold, mercury, tin and nickel ... 

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