Copper as catalysts

Aldehydes are formed by the reduction of the ester of the corresponding acid to the alcohol, and then oxidising the alcohol with heated copper as catalyst. It is well known that when primary alcohols in the gaseous state are passed over finely-divided copper dust, obtained by reduction of copper oxide, at 250° to 400°, they yield hydrogen, and aldehydes or ketones respectively. 

The ester group of in ethyl dibenzo[/>,c/]thiepin-7-carboxylate can be hydrolyzed by alkali to the free acid in 93 % yield. Subsequent decarboxylation in quinoline at 150°C with copper as catalyst provides dibenzo[/ ,r/]thiepin in 60% yield.5... 

Pyridyldiazoalkanes 16, when pyrolyzed with or without copper as catalyst, give triazolopyridines among other products.22 Other reactions that probably involve pyridyldiazoalkanes as intermediates are noted in Sections I,A,l,b and c. 

Samuelsson (1966) concluded, on the basis of his studies, that the close proximity of a copper-protein complex to the phospholipids which are also associated with the fat globule membrane is an important consideration in the development of an oxidized flavor in fluid milks. Haase and Dunkley (1970) stated that although some aspects of catalysis of oxidative reactions in milk by copper still appear anomalous... the mechanism of oxidized flavor development with copper as catalyst involves a specific grouping of lipoprotein-metal complexes in which the spatial orientation is a critical factor. ... 

Many other industrial methods are now employed e.g. one starts (22) with anthranilic acid which is diazotised and treated with liquid sulfur dioxide in presence of copper as catalyst. The sulphinic acid derivative thereby obtained is treated with chlorine in alkaline solution and sulfonyl chloride so obtained is treated with ammonia and heated. 

If ethylchlorosilanes are desired, they may be made by the direct method by the vapor-phase reaction of ethyl chloride with silicon at 300° C., using 10 per cent of copper as catalyst.8 The reactions follow the general plan indicated in the flow sheet for the corresponding methyl compounds (Fig. 2). 

Trisubstituted furans were afforded in moderate to good yields from the reaction of acetylenic ketones and diazoacetates by utilizing copper as catalyst <07JOC10276>. 

Displacement of aromatic halogen. With both cuprous chloride and copper as catalyst 4-bromo-o-xylene can be converted into the corresponding amine. The... 

Tetrafluorobutylsulfonylbicyclo[4.1.0]heptane-7-carbonitrile (1) was obtained by the decomposition of phenyliodonium cyano(tetrafluorobutylsulfonyl) methanide, with bis(acetyl-acetonato)copper as catalyst and traces of benzoyl peroxide, in the presence of cyclohexene. It has been proposed that the reaction proceeds by the initial formation of a cyanocarbene, which then attacks the C-C double bond of cyclohexene. ... 

However, when the reaction is performed in methylene dichloride in the presence of catalytic amounts of metallic copper, the iV-monophenylated amine derivatives are obtained in preparatively useful yields. Phenylation of aliphatic and aromatic amines with triphenylbismuth diacetate and metallic copper (ratio 1 1.1 0.1) in methylene dichloride at room temperature led to good to high yields of the derived anilines (up to 96% based on the amine). In the case of less reactive substrates, use of copper diacetate instead of metallic copper as catalyst constitutes a more reactive system which allows the preparation of the A -phenyl derivatives in moderate yields. These yields can also be improved by performing the reaction at a higher temperature. 

While Trillat and Orloff both emphasized the advantages to be gained by the use of platinum and copper as catalysts in the oxidation of the alcohols, their respective interpretations of the mechanism of the reactions involved in these processes differed very widely. Thus, while the former regarded oxidations in the presence of these metals as reversible reactions, the latter held more strongly to the view that they belong definitely to the class of non-reversible processes. Orloff18 based his reasoning upon mathematical and thermodynamical interpretations of the oxidation reactions. 

By using pumice, asbestos, or copper as catalysts, Clock 14 claims the formation of acetaldehyde, acetic acid, and ethanol from the oxidation of ethane. The fact that practically the same conditions of operation are used for ethane as were used for methane oxidation makes it seem rather doubtful that products having the same number of carbon atoms as the original ethane should have been obtained in view of the fact that methane is much more resistant to oxidation than ethane and requires more severe treatment. 

Aryl halides containing less reactive halogen can also be converted into sulfides by thiols if heavy-metal (lead, zinc, mercury) thiols are used at 225-230° 1-naphthyl, 2-naphthyl sulfide,301 1- and 2-naphthyl phenyl sulfide,302 and 1-and 2-naphthyl o-, m-, and p-tolyl sulfide303 have been obtained in this way. When the heavy-metal thiolates are too stable and do not react with aryl bromides even at 240°, the aryl sulfides can nevertheless often be prepared by a generally applicable reaction of aryl iodides with sodium thiolates under the influence of copper as catalyst.304... 

Methylsilyl chloride has acquired considerable industrial importance as a precursor for the preparation of silicon it is prepared directly by reaction of methyl chloride with silicon in the presence of copper as catalyst at high temperatures.317 Details for direct synthesis of methylsilyl chlorides have been given by Rochow.318 The main product is dichloro(dimethyl)silane in accordance with a reaction 2CH3C1 + Si - (CH3)2SiCl2, but trichloro(methyl)-silane, trimethylsilyl chloride, tetramethylsilane, silicon tetrachloride, and other products are also formed. 

Although the by-produpts in each step of this process are advantageously employed in some phase of the synthesis, it is obvious, from the description below, that relatively large quantities of materials (4.3 lb per lb phenol) have to be handled. The process of the Dow Company, which accounts for a substantial percentage of domestic production, starts from chlorobenzene, hydrolyzing it under high pressure in an aqueous alkaline solution with copper as catalyst. 

Some of the optimized procedures for Stille and Sonogashira reactions involve the addition of copper cocatalysts to accelerate the cross-coupling procedures. A word of caution should be provided on the role of these additives in Pd-catalyzed amination procedures. Beletskaya and Davydov have reported the arylation of benzotriazole and of diary-lamines in polar organic or aqueous organic solvents using a combination of palladium and copper as catalyst.The arylation of amino acids has been reported under similar conditions.However, these reaction conditions are similar to classic Ullmann procedures for the synthesis of arylamines, except for the addition of palladium to the reaction mixture. In one case, subsequent work showed that the palladium species was not an essential component and that copper alone was the true catalyst in their reactions. An unusual accelerating effect of amino acid coordination to copper was used to explain the low-temperature Ullmann conditions. Beletskaya, however, showed that lower yields and a mixture of N1 and N2 arylation products were observed from the reactions of benzotriazole in the absence of copper and no reaction was observed in the absence of palladium. The conditions for this chemistry are, however, distinct enough from those of the majority of the aryl halide aminations to support the idea that a different mechanism may operate. 

Producing of Polyarylenoxides using Carbonates of Alkali-Earth Metals, Salts of Organic Acids and, in Some Cases, salts of Copper as catalysts. US Patent 4774314. 

Producing of polyarylenoxides using carbonates of alkali-earth metals, salts of organic acids and, in some cases, salts of copper as catalysts, US Patent 4774314. 

A flow injection fluorimetric method has been reported for the determination of thiamin using copper as catalyst (Perez-Ruiz et al. 1992). Thiamin is oxidized to produce fluorescent thiochrome by copper(ii) in basic medium. The method is successfully applied to determine thiamin in pharmaceutical samples. 

Potassium perfluorobenzoates were shown to undergo decarboxylative coupling with aryl hahdes using copper as catalyst without needing to use Pd [7] (Scheme 4.3). 

Boomer EH, Thomas V. The oxidation of methane at high pressures. III. Experiments using pure methane and principally copper as catalyst. Can J Res Sect B 1937 15 414-33. 

Note that if these reactions are combined, as in the Wacker process, the net reaction is (8.2.1.4). In other words, in the Wacker process 1 mol of ethylene and Vi mol of dioxygen is reacted in the presence of palladium and copper as catalysts, to give 1 mol of acetaldehyde. 

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