Cupric oxide

Cholestenone. Place a mixture of 1 0 g. of purified cholesterol and 0-2 g. of cupric oxide in a test-tube clamped securely at the top, add a fragment of Dry Ice in order to displace the air by carbon dioxide, and insert a plug of cotton wool in the mouth of the tube. Heat in a metal bath at 300-315° for 15 minutes and allow to cool rotate the test-tube occasionally in order to spread the melt on the sides. Warm with a few ml. of benzene and pour the black suspension directly into the top of a previously prepared chromatographic column (1) rinse the test-tube with a little more benzene and pour the rinsings into the column. With the aid of shght suction (> 3-4 cm. of mercury), draw the solution into the alumina column stir the top 0 -5 cm. or so with a stout copper wire to... 

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°. 

Alkoxythiazoles are prepared by heterocyclization (274, 462). The Williamson method using catalytic amounts of KI and cupric oxide is also possible (278. 288, 306). 5-Acetoxy-4-alkenylthiazoles are obtained by treatment of 242 with acetyl chloride and triethylamine or with acetic anhydride and pyridine (450). Similarly, the reaction of diphenylketene with 242 affords 5-acyloxy-4-alkenylthiazoles (243) (Scheme 120) (450). The readiness of these o-acetylations suggests that 4-alkylidene thiazoline-5-one might be in equilibrium with 4-alkenyl-5-hydroxythiazoles (450). 

Koch Ro- ction. C-6-neoacids are readily available from amyl alcohols by the Koch reaction. Greater than 95% 2,2-dimethylbutyric acid [595-37-9] was obtained from 2-methyl-1-butene at 304 kPa (3 atm) CO and 35°C for 1 h with cupric oxide and sulfuric acid catalyst (31). Likewise,... 

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. 

Although both cuprous and cupric fluorides have been studied in the past, an active fluorine donor can be formed from cupric oxide and hydrogen fluonde. This donor, in combination with 2,2 -bipyridine, effectively displaces the halogen of... 

Methoxythiophene and 3-cyanothiophene have been prepared from 3-bromothiophene by means of a cupric oxide-catalyzed Williamson synthesis and by reaction with cuprous cyanide in quinoline, respectively. 

Cupri-. cupric, copper(II). -azetst, n. cupric acetate, copper(II) acetate, -carbonat, n. cupric carbonate, copper(II) carbonate, -chlorid, n. cupric chloride, copper(II) chloride. -hydroxyd, n. cupric hydroxide, cop-per(II) hydroxide. -ion, n. cupric ion, copper(II) ion. -ozalat, n. cupric oxalate, copper(II) oxalate, -oxyd, n. cupric oxide, copper(II) oxide. -salz, n. cupric salt, copper(II) salt, -suifat, n. cupric sulfate. copper(II) sulfate, -sulfid, n. cupric sulfide, copper(II) sulfide, -verbihdung, /. cupric compound, copper(II) compound, -wein-saure, /. cupritartaric acid. 

Kupferoxyd, n. cupric oxide, copper(II) oxide, -ammoniak, n. ammoniacal copper oxide, cu-prammonium. -ammoniakkunstseide, -am-moniakzellulose, /. cuprammonium rayon, -hydrat, n. cupric hydroxide, copper(II) hydroxide. -salz, n. cupric salt, copper(II) salt. 

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. 

The hydrolytic step (Part D) uses conditions described by Narasaka, Sakashita, and Mukaiyama.11 It was necessary to modify the original stoichiometry, since the recommended molar ratio of substrate cupric chloride cupric oxide (1 2 4) gave only a 57% yield of 3-bcnzoylindole. 

Cupric oxide [Copper oxide (CuO)], 10 Cyclodecanone, 111 Cyclododecanone, 108 Cyclododecanone, 2,12-dibromo-, 107 1 -Cy cloheptene, 1 -bromo-7 -acety loxy-[2-Cyclohepten-l-ol, 2-bromo-, acetate], 34... 

Mg ribbon and fine Mg shavings can be ignited at air temps of about 950°F (Ref 26). Oxides of Be, Cd, Hg, Mo and Zn can react explosively with Mg when heated (Ref 8). Mg reacts with incandescence when heated with the cyanides of Cd, Co, Cu,Pb, Ni or Zn or with Ca carbide (Ref 9). It is spontaneously flam-mable when exposed to moist chlorine (Ref 10), and on contact with chloroform, methyl chloride (or mixts of both), an expl occurs (Ref 4). Mg also reacts violently with chlorinated hydrocarbons, nitrogen tetroxide and A1 chloride (Ref 14). The reduction of heated cupric oxide by admixed Mg is accompanied by incandescence and an expin (Ref 7).Mg exposed to moist fluorine is spontaneously flammable (Ref 11). When a mixt of Mg and Ca carbonate is heated in a current of hydrogen, a violent ex pin occurs (Ref 12). When Mo trioxide is heated with molten Mg, a violent detonation occurs (Ref 1). Liq oxygen (LOX) gives a detonable mixt when... 

Vaporous copper may be particularly damaging because it forms cuprous and cupric oxide deposits on turbine blades. 

Heterogeneous reactions these various processes are cyclic and continuous, taking place in all sections of the boiler from the economizer to the condensate lines and including suspended ferric oxide and cupric oxide particles. Unless the hydrazine overfeed is extremely substantial (say, six to seven times theoretical), these latter reactions tend to predominate ... 

In fact, following oxygen scavenging, the balance of hydrazine then proceeds to reduce any cupric oxide to reform a protective, passivated cuprous oxide layer. This premise is, of course, dependent on effective post-boiler scavenging. 

The ammonia production is less than in hydrazine, but there may be a perceived of copper and brass corrosion. In fact, any corrosion risk is small, provided that DEHA-treated boiler plants are subjected to the same requirements as hydrazine-treated units, namely, ensuring that all in-leakage of oxygen in the condensate system is fully eliminated. If this objective is achieved, the oxidation of cuprous oxide to cupric oxide tends not occur to any significant degree, and the susceptibility for copper corrosion in the presence of ammonia is equally low. 

Copper salts usually are the result of corrosion in the post-boiler section and may be present as red cuprous oxide (Cu20), black cupric oxide (CuO), or blue-green copper sulfate (CuSO ). Mostly, copper salts are mixed with hematite and magnetite and take on a black color. 

Complexing, using a complexing agent such as thiourea or ammonia, for example, to remove mixtures of cuprous oxide, cupric oxide, and plated copper metal. 

When cleaning boilers containing iron-copper deposits (with, say, hydrochloric acid), unless special precautions are taken, the cupric oxide dissolves and the cupric ion is reduced to copper, which then replates onto the steel surface, thus beginning the corrosion cycle again. 

From the first of the two reactions shown, it can be seen that in the acid cleaning solution the cupric ion (Cu2+) is formed from cupric oxide. The thiourea component then reduces the cupric ion to the cuprous ion (Cu+) and, in a series of reactions, complexes it, essentially preventing the cupric ion from ultimately plating out as copper. 

Kolbel et al. (K16) examined the conversion of carbon monoxide and hydrogen to methane catalyzed by a nickel-magnesium oxide catalyst suspended in a paraffinic hydrocarbon, as well as the oxidation of carbon monoxide catalyzed by a manganese-cupric oxide catalyst suspended in a silicone oil. The results are interpreted in terms of the theoretical model referred to in Section IV,B, in which gas-liquid mass transfer and chemical reaction are assumed to be rate-determining process steps. Conversion data for technical and pilot-scale reactors are also presented. 

Concentration of reactants As an example of this factor, mention may be made of the dissolution reaction of cupric oxide in acids... 

The standard free energy change for this reaction is generally positive at all temperatures because oxides are invariably stabler than chlorides. An exception to this rule occurs in the case of copper because cupric chloride is more stable than cupric oxide. At 500 °C, the standard free energy change (AG°) for the reaction... 

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