Cupric oxide water

In a 1 litre round-bottomed flask, equipped with an air condenser, place a mixture of 44 g. of o-chlorobenzoic acid (Section IV,157) (1), 156 g. (153 ml.) of redistilled aniline, 41 g. of anhydrous potassium carbonate and 1 g. of cupric oxide. Reflux the mixture in an oil bath for 2 hours. Allow to cool. Remove the excess of aniline by steam distillation and add 20 g. of decolourising carbon to the brown residual solution. Boil the mixture for 15 minutes, and filter at the pump. Add the filtrate with stirring to a mixture of 30 ml. of concentrated hydrochloric acid and 60 ml. of water, and allow to cool. Filter off the precipitated acid with suction, and dry to constant weight upon filter paper in the air. The yield of iV-phenylanthranilic acid, m.p. 181-182° (capillary tube placed in preheated bath at 170°), is 50 g. This acid is pure enough for most purposes. It may be recrystaUised as follows dissolve 5 g. of the acid in either 25 ml. of alcohol or in 10 ml. of acetic acid, and add 5 ml. of hot water m.p. 182-183°. 

Copper Corrosion Inhibitors. The most effective corrosion inhibitors for copper and its alloys are the aromatic triazoles, such as benzotriazole (BZT) and tolyltriazole (TTA). These compounds bond direcdy with cuprous oxide (CU2O) at the metal surface, forming a "chemisorbed" film. The plane of the triazole Hes parallel to the metal surface, thus each molecule covers a relatively large surface area. The exact mechanism of inhibition is unknown. Various studies indicate anodic inhibition, cathodic inhibition, or a combination of the two. Other studies indicate the formation of an insulating layer between the water surface and the metal surface. A recent study supports the idea of an electronic stabilization mechanism. The protective cuprous oxide layer is prevented from oxidizing to the nonprotective cupric oxide. This is an anodic mechanism. However, the triazole film exhibits some cathodic properties as well. 

As for the turbines, no steam-purifying equipment of the type used on drum boilers is feasible, so that the steam from super-critical boilers tends to be of inferior quality. Deposits have been reported of cuprous oxide on the extra high-pressure turbines and of cupric oxide on some high-pressure turbines of sub-critical plant. These deposits may lead to a loss of efficiency and to some risk of corrosion. At intervals, slugs of solute are carried over in the steam, which is therefore of fluctuating quality. This is countered by periodic water-washing of the boilers. 

This is an improved version of a previously given synthesis (LAC 630,71(1960)). The ethanol used is distilled from Ca ethoxide dimethoxyethane from potassium. Cupric bromide is produced from cupric oxide and 5% excess of HBr, plus sufficient bromine to remove the milkiness on addition of a drop of the mixture to water concentrate and dry, evaporate in vacuum over KOH flakes. 

To continue the process, the fatty methyl esters are phase-separated from the glycerin (or glycerol—same thing, just to keep you on your toes), washed with water to remove any trace amounts of methanol and glycerin and dried. In a second reaction, the methyl esters are hydrogenated to get the fatty alcohols (in the southeast corner of Figure 15—2). The catalyst is usually a mixture of cupric chromite and cupric oxide in the form of a finely divided powder. Conversion of the triglycerides is about 95%. 

Valine.—This amino acid is contained mixed with leucine in the fractions of the esters which boil between 6o° and 90° C. Its isolation and separation from leucine is of extreme difficulty, since these compounds, as well as their copper salts into which they are converted by boiling with freshly precipitated cupric oxide, tend to form mixed crystals. Its isolation was only effected by these means in certain cases, and its amount is really much more than the figures represent from its yield. It is best characterised by conversion into its phenylhy-dantoine derivative by treatment with phenyl isocyanate in alkaline solution. The phenylureido acid is first formed, and this loses a molecule of water, as shown by Mouneyrat, and is changed into its anhydride or phenylhydantoine by treatment with hydrochloric acid. The following reactions occur —... 

Copper forms practically aU its stable compounds in -i-l and +2 valence states. The metal oxidizes readily to -i-l state in the presence of various com-plexing or precipitating reactants. However, in aqueous solutions +2 state is more stable than -i-l. Only in the presence of ammonia, cyanide ion, chloride ion, or some other complexing group in aqueous solution, is the +1 valence state (cuprous form) more stable then the +2 (cupric form). Water-soluble copper compounds are, therefore, mostly cupric unless complexing ions or molecules are present in the system. The conversion of cuprous to cupric state and metalhc copper in aqueous media (ionic reaction, 2Cu+ — Cu° -i- Cu2+) has a Kvalue of 1.2x106 at 25°C. 

Diammino-eupric bromide is very dark in colour it is soluble in a concentrated aqueous solution of ammonium bromide, from which it may be crystallised water alone decomposes the ammine completely. It is capable of absorbing ammonia gas, forming the higher ammino-derivatives, and it may be heated to 200° C. without decomposition. At 260° C. it begins to decompose, and above that temperature it loses ammonia, leaving a residue of cupric bromide and some cupric oxide.2... 

The stabilities of the triammino-cuprous halides are almost identical, and the dissociation pressures of the ammino-cupric halides lie very near together.6 The stabilities of hexammino-copper halides is also almost identical the compounds are very readily decomposed by water, and hence do not seem to be formed in aqueous solution. Ammino-derivatives of cupric carbonate, cupric acetate, cupric oxide, and cuprous cyanide and thiocyanate are known. These have the general characteristics of the ammines already described. 

Boiling in water (Wohler and Krupko [80]) leads to hydrolysis with the formation of basic cupric azide. Long-continued boiling causes complete hydrolysis to cupric oxide and free acid. Black cupric azide, Cu(N3)2, when exposed to the action of air for 2 months, is completely converted into a yellow basic salt. This is discussed later. 

Hydrogen telluride was also the starting-point in the investigation of Bruylants and Michielsen.3 The gas after careful purification was decomposed into its elements at 200° to 220° C., the tellurium weighed as such and the hydrogen oxidised to water by means of cupric oxide. The value obtained was 127-8. 

Another typical property of cellulose and its derivatives dependent on water sorption is the swelling of the fibre that occurs under the influence of certain solutions such as aqueous sodium hydroxide or an ammoniacal solution of cupric oxide, i.e. cuprammonium . The process of swelling does not start with sorption as in the instance of water. In the first stage of swelling the liquid penetrates the molecular chains of the cellulose, gradually coming in contact with all of them so that chemical combination takes place to form alkali celluloses, (C6H,0O5) NaOH and (C6H,0O5)2 NaOH. 

It remains to be noted that, when there is no method available for ascertaining the formula weight or a compound, the simplest formula, based on chemical analysis and the use of symbol weighLs of the contained elements, is used, e g., ferric oxide, FejOj, ferroferric oxide, FejCXt, ferrous oxide, FeO, cupric oxide (black copper oxide), CuO. cuprous oxide (red copper oxide). CujO. The customary formula of water is H2O. which is correct ai temperatures above I00°C—actually, liquid water is mainly dihydrol (HjOh. 

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