Copper reducing action

The aldehyde may be distinguished fiom the ketone by its reducing action on alkaline copper sulphate, ammonia-sih er nitrate and by SchifPs test (see Reactions, p. 67). 

While the mechanism for the deposition was not discussed, the instability of the copper hydroxides (the hydroxide of Cu(I) probably does not even exist) toward dehydration, together with the reducing action of the thiosulphate, leads to the expectation that CU2O will be the product of the hydrolysis of Cu(I) in alkaline solution. It should be noted, however, that the Cu-thiosulphate solution itself is not very stable and apparently forms predominantly Cuj S in the absence of NaOH. 

Cadmia, it will be remembered, is the impure zinc oxide, containing sometimes lead and copper oxides, from the furnaces in which brass was smelted. Misy was the partly oxidized iron or copper pyrites, essentially basic sulphates of iron and copper. Synopian red was haematite. This mixture, assuming the reducing action of the fuel in the furnace, or of any other reducing agent not specified in the recipe would yield an alloy of gold and zinc, with some copper and perhaps some lead. 

Nitric acid dissolved in sulphuric acid is reduced eleetrolytieally at an amalgamated cathode almost exclusively to hydroxylamine, although such a cathode has a distinct electrolytic reducing action on hydroxylamine sulphate. On the other hand, nitric acid is reduced almost completely to ammonia at a copper cathode which is effective only at... 

On the reducing action of oarbon monoxide on ammonio-copper carbonates, compare Hainsworth and Titus, J. Amer. Chem. Soc., 1921, 43, 1. 

If starch is composed of linear and branched chains of glucopyranose units, there should be a potential free aldehyde group at one terminus of the molecule. The slight reducing action of starch toward alkaline ferricyanide or copper salts reflects the presence of this terminal aldehyde, though these methods have not had satisfactory quantitative application to starch. 

At the base of the pits where reducing action accompanies corrosion, copper deposition can be seen. Copper comes from corrosion of bronze circulating pumps, phosphor-bronze fittings and copper alloy lines. These cooling systems could have been well protected by a chromate inhibitor, or by a borate-nitrite-MBT product, but experienced accelerated attack when using the improper phosphate-silicate inhibitor. 

The identity test of the B.P. has been modified for tablets and injections by Allport and Jones to give quantitative results. The colour is stable when extracted by ry< /ohexane and deeper than in ethereal solution. Lactose interferes because of its reducing action on copper sulphate. 

Maitodextrin is the general term apphed to non-crystalline copper-reducing intermediate products of the action of diastase on starch. 

Usually prepared by the action of NaCN on benzaldehyde in dilute alcohol. It is oxidized by nitric acid to benzil, and reduced by sodium amalgam to hydrobenzoin PhCHOHCHOHPh by tin amalgam and hydrochloric acid to des-oxybenzoin, PhCH2COPh and by zinc amalgam to stilbene PhCH = CHPh. It gives an oxime, phenylhydrazone and ethanoyl derivative. The a-oxime is used under the name cupron for the estimation of copper and molybdenum. 

The action of redox metal promoters with MEKP appears to be highly specific. Cobalt salts appear to be a unique component of commercial redox systems, although vanadium appears to provide similar activity with MEKP. Cobalt activity can be supplemented by potassium and 2inc naphthenates in systems requiring low cured resin color lithium and lead naphthenates also act in a similar role. Quaternary ammonium salts (14) and tertiary amines accelerate the reaction rate of redox catalyst systems. The tertiary amines form beneficial complexes with the cobalt promoters, faciUtating the transition to the lower oxidation state. Copper naphthenate exerts a unique influence over cure rate in redox systems and is used widely to delay cure and reduce exotherm development during the cross-linking reaction. 

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